assemblage SET-300B Construction And Operation Manual

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Construction and Operation Manual

A S S E M B L A G E

S E T - 3 0 0 B P O W E R A M P L I F I E R

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Dear Assembler,

Congratulations on purchasing the Assemblage SET-300B power amplifier. We are very proud of the Assemblage SET-300B, both technically and perhaps more import a n t l y, sonically. Utilizing modern, high quality parts, the SET-300B has been designed to pro v i d e many years of tro u b l e - f ree operation, using readily available tube types (these are tube types, which are still in production - and will continue to be so).

Assemblage SET-300B Assembly Manual

Page Contents

4 P a rts List 5 Tools re q u i re d 6 S E T-300B Functions 8 B e f o re You Start 9 Stripping/soldering instru c t i o n s 1 0 Assembled PC Board s 1 1 Main PC Board Parts Placement Guide 1 2 Assembly Instru c t i o n s

1 4 S c h e m a t i c s 1 9 Mono Block Operation Setup 2 5 Tro u b l e s h o o t i n g 2 5 Assemblage SET-300B Signature Upgrade and Pre v i e w 2 6 S p e c i f i c a t i o n s 2 7 F u t u re Upgrades 2 7 Guarantees and Wa rr a n t y

• Initial pre p a r a t i o n - p a rts count schematic/numbering conventions

• First stage - board stuff i n g

• Second stage - bottom cover feet, transformer removal, installation of RCA jacks, mute switch, binding posts, 300B sockets, IEC module & input signal cable.

• T h i rd stage - wiring of power transform e r, output transformers, choke, IEC socket, and correct configuration of power transformer primary windings (e.g. 100/120/200/220/240 V).

• F o u rth stage - installation of PC board s

• Fifth stage - faceplate & power switch shaft mounting.

• Sixth stage - final check

• Seventh stage - last step

Warning and Disclaimer of Liability

When constructing this kit, take care that the assembly steps are followed pre c i s e l y. Be aware that there will be dangerous high voltages present in the amplifier. Under no circumstances does The Parts Connection or Sonic Frontiers International assume liability or responsibility for injury or damages sustained in the operation or assembly of this equipment, or for damages to any equipment connected to it. If you have any questions re g a rding the assembly or set up of the SET-300B, please do not hesitate to contact us.

2790 Brighton Road, Oakville, Ontario,Canada L6H 5T4

Toll Free: 1-800-769-0747 (U.S. and Canada) Telephone: (905) 829-5858 Facsimile: (905) 829-5388 Web Site: http://www.sonicfrontiers.com/TPC E-mail: [email protected]

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Parts List

Please note, if you are planning to install the Signature Parts Upgrade kit at this same time, take note of the parts labeled “Sig.” in this manual. Refer to the Parts Upgrade Instructions for these replacement parts.

I t e m / Va l u e Q t y / U n i t R e f e rence Designators

Printed Circuit Boards

q Main Board 1 L a rge main PCB q Power Supply PCB’s 3 Filter Banks Main, Left and Right q AC Switch PCB 1 Side mounted switch PCB

Semiconductors

q TL400G Bridge - 4A 200PIV 2 BR100; LBR100 q RB151 Bridge - 1A 1000PIV 1 B R 4 0 0 q SF4007 - 1A 1000PIV 4 D1, 2; LD1, 2 q LED - Coool Blue 1 L E D 1

Capacitors

q 0.1uF 50VDC 3 CC1, CC2, CC3 q 0.47uF 400VDC (Sig) 2 C3; LC3 q 470uF 16VDC (Sig) 2 C1; LC1 q 100uF 100VDC (Sig) 2 C4; LC4 q 220uF 160VDC 2 C2; LC2

q 10uF 450VDC 5 C5, C6, C300; LC5, LC6 q 100uF 400VDC 2 C200A, C200B q 220uF 400VDC 4 C202A, C202B; LC202A, LC202B q 470uF 400VDC 2 C201A, C201B q 4700uF 16VDC (Sig) 5 C100, C101, C400; LC100, LC101 q 0.1uF 275VA C 1 A C 1

Resistors 1/2W

q 1K Metal Film (Sig) 2 R2; LR2 q 1K2 Carbon 1 R F 1 q 100R H4 HOLCO (Sig) 4 R5, R8; LR5, LR8

q 100R Metal Film 8 R11, R12, R301, R302, R400,

q 475R Metal Film (Sig) 2 R3; LR3 q 100K H8 HOLCO 2 R1; LR1 q 249K Metal Film (Sig) 2 R10; LR10

Resistors 1-2W

q 220K 2W 8 R205A, R205B, R206A, R206B,

q 33K 2W (Sig) 2 R4; LR4 q 68K 2W 4 R209A, R209B; LR209A, LR209B q 100K 2W 1 R 3 0 0 q 150K 2W 2 R210, LR210

R401; LR11, LR12

R208A, R208B; LR208A, LR208B

Chassis Components

q Main Chassis 1 q Main Chassis Bottom Cover 1 q F ront Panel - Aluminum 1 q Switch Button 1

Transformers/Choke

q O/P Tr a n s f o rm e r s 2 q Power Tr a n s f o rm e r 1 q 4H 250ma Choke 1

Vacuum Tubes

q 6SN7GT / 6H8C 1 V 2 q 6 B X 7 G T 2 V1, V3 q G Z 3 7 2 V6, V7

Chassis Mounted Hardware

q RCA Jack - RED (Sig) 1 RCA Audio I/P Right q RCA Jack - WHITE (Sig) 1 RCA Audio I/P Left q Toggle Switch 1 Mute Switch q DPST AC power switch 1 AC power switch q 4 Pin Ceramic Socket 2 300B sockets q Dual Binding Posts (1pr) (Sig) 2 Speaker Posts q IEC Socket 1 AC Input q Black Rubber Chassis Feet (Sig) 4 Chassis bottom cover q Solder lug #6 3/4” 2 Solder Lug q Fuse 2.5A or 1.25A Slo-Blo 1 F 1

Mounting Hardware

q M3 10mm (3/8”) Blk CS scre w 2 IEC socket q #6-32 x 1/4” Zinc Philips 2 Solder lug attachment,

q #6-32 x 1/4” Blk Philips 1 2 Holds bottom cover q #6-32 x 3/4” SS Philips 4 F e e t q #8-32 3/8” Blk Philips 2 Holds Choke q #10-32 3/8” Blk Philips 1 2 Tr a n s f o rm e r s q #10 Blk Split Wa s h e r 1 2 Tr a n s f o rmers q Nylon Wa s h e r s 4 300B tube sockets q #6-32 kepnut 4 Holds 300B Sockets q #8-32 kepnut 2 Holds Choke q #10-32 kepnut 2 Holds Faceplate

I/P Com. to Chassis

Resistors 5W

q 5R6 3W 4 R200, R201, R202, R203 q 10k 3W (Sig) 2 R6; LR6 q 0.56R 5W 4 R100, R101; LR100, LR101 q 1K 5W 2 R207; LR207 q 3K 5W 4 R13B, R13C; LR13B, LR13C q 3K9 5W 4 R13, R13A,; LR13, LR13A q 10K 5W 2 R7; LR7

q 15K 5W 4 R9A, R9B; LR9A, LR9B q 6R8 5W 1 (+HV See text)

Trimpot

q 200R 1/2W 2 VR1, LV R 1

PC Board Hardware

q 8 Pin PCB Mount Octal 5 V1, V2, V3, V6, V7 q #4-40 1/2” Stand-off 1 0 Under V1, V2, V3, V6, V7 q #4-40 1/4” SS Philips PH 2 0 V1, V2, V3, V6, V7 Stand-off’s q #4 Lock Wa s h e r 1 0 V1, V2, V3, V6, V7 Stand-off’s q #6-32 1/4” SS Philips PH 2 2 Holds PCB’s to Chassis Stand-off’s q #6 Lock Wa s h e r 4 AC SW PCB & Under Gro u n d

S c rews

Hookup Wires & Associated

q Shielded 4 conductor (Sig) 24” Shielded input cable q Hook-up Black 18awg 48” IEC socket, Spkr posts, Filter Banks q Hook-up Green 18awg 24” G round wiring q Hook-up Red 18awg (Sig) 12” power supplies B+, B+1 q Hook-up Brown 18awg 12” power supplies B+2, LB+2 q Hook-up Blue 18awg 1 2 ” power supply B+3, LB+3 q Heat-shrink tubing Black 1 / 8 ” 6” IEC Te rminals & LED q Heat-shrink Tubing Black 3 / 1 6 ” 6” I/P and AC primary wiring q #30 Twist Connectors 4 O/P Transformer Secondary

q Kimber Kable TCSS (Sig) 4” To 300B Grids

Miscellaneous

q 3” Cable Ti e s 8 Tr a n s f o rmer wire s q Cable Tie Mounts 1 Power transformer wire s q Extension Shaft 2 AC Switch to Front panel button q Shaft Coupler 2 AC Switch to Front panel button q Nylon Blk Hole Plug 1 Hole plug for Level Control

q Wo n d e r s o l d e r 1 0 f t q S o l d e rw i c k 1 f t q 18/3 CSA Power Cord 6 Foot 1 q C o n s t ruction and Operation Manual (If you cannot locate this, we are in big tro u b l e ! ) q Wa rranty Card

Configurations

k n o c k o u t

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Tools Required

In addition to the parts supplied in the kit, you will need the following tools to complete construction of the SET-300B kit.

1 Pencil tip soldering iron of good quality (700°F tip temperature) 1 #0 Philips screwdriver 1 12mm wrench or ratchet (1/2” will also work) 1 10mm combination wrench (not shown) (3/8” will also work) 1 5/16” nut driver 1 Pair of needle nosed electronics pliers 1 Wire stripper or hobby knife (If you trust yourself with your fingers!) 1 Ruler/Scale (not shown) 1 Voltmeter (optional)

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SET-300B Functions

C D E D

GEF

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Control Functions

A LED

When the coool blue LEDis lit, the SET-300B is “ON”, receiving power from the power supply.

B ON-OFF button

When in the ON position (button depressed), high voltage power is received by the SET-300B circuitry f rom the power source. Due to the warm up characteristics of tubes, it will take 30 seconds for the tubes to pass full signal. It is suggested that the SET-300B remain muted or the volume control on the preamp be turned down for this first minute. When in the OFF position (not depressed), the SET-300B is not receiving power and is not operational.

Connection Functions

C Detachable AC Power Cord Socket

Plug the Detachable Power Cord into this socket.

D Speaker Connection Posts

These 5-way binding posts accept a connection from one pair of speakers. The negative connections are to be made to the black connectors; left speaker to the terminals marked left and right to the terminal marked right.

E Preamplifier Input

This input accepts RCA input connections from an external preamp or crossover; connect left channel to left channel and right channel to right channel.

F Mute/Operate Switch

The input of the 300B may be muted via this switch. This is handy when changing interconnect cables or even isolating system components for tro u b l e shooting purposes.

G Optional Set - Control

This level control may a switched attenuator or potentiometer from TPC or one of your own favorites. This will allow a source device to be dire c t l y connected to the amplifier input jacks there b y bypassing an outboard preamp.

WARNING - DISCONNECT T H E AC D E TAC H A B L E P OW E RC O R DF RO MT H ES E T- 3 0 0 B AND WAIT 5 MINUTES BEFORE REMOVING BOT TOM COV E R , TUBES OR FUSE.

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Before You Start - Kit Overview

B e f o re you start assembling your SET-300B, please take a few minutes to read this preface on the construction manual and the kit.

Zen and the Art of Electronics Assembly:

Assembling a high quality electronic device re q u i res a certain frame of mind. The object is not to rush through and get the kit assembled as quickly as possible, but to methodically and correctly put together the pieces of this audio jigsaw puzzle. The kit could take as long as 68 hours to complete, so plan your attack accordingly and take bre a k s often, you will find the natural places to do so as you go through the assembly steps. The final kit appearance will benefit from your re s t e d m i n d . If the instructions are followed to the letter, the amplifier will work c o rrectly right from the start. If you try to assemble the kit purely fro m the pictures/illustrations without reading the body of the text, your unit will most likely not work. Please note that this kit is not intended for the complete novice. A c e rtain level of competency is assumed in electronics assembly - i.e. the ability to solder, and to be able to use a voltmeter/multimeter.

General Instructions:

W h e re necessary a simple overview of the upcoming step is p resented to you before you actually do that pro c e d u re. This little p reamble will help to clarify the next assembly step and give you a b roader understanding of the construction methods to use, and hopefully aid you in getting it right the first time. Following this is a list of the parts or components that will be needed or constructed in this immediate section, then a detailed description of the assembly p ro c e d u res for that section.

The top of the printed circuit boards is the one side that has the white s i l k - s c reening on it. There f o re you know that the backside has no s c reening on it and no parts, except it is the backside that the tube sockets will be mounted to.

Parts Count:

While every precaution has been taken to ensure that you have received a complete kit, your kit has been picked and packed by humans. There f o re, please use the Parts List on page 4, to ensure that you have all parts present and accounted for. Before you convince yourself that something is missing, check again! Larg e c a rd b o a rd boxes are notorious for hiding small parts, as are the packing materials.

Stuffing the PC Boards:

If you inspect the main board (this is the largest of the boards with which your are supplied with), you will notice that all parts locations have been labeled with the appropriate part re f e rence designator. Each diff e rent set of components has been placed in its own individual bag, which has its own label which lists the part type. (Yo u will find the re f e rence designators listed on the Parts List.) There f o re , when you are asked to install the resistor R1, you simply pro c u re the labeled bag with that part in it. Once the part is installed and soldere d in place, you can check that component off the supplied checklist in this manual. There are also several photos and diagrams detailing p a rts placement to reduce any possible confusion that may arise re g a rding parts placement. Please note too, that there may be some subtle diff e rences between some of the parts shown in the photographs and those supplied with your kit. On occasion, our technical staff may substitute parts with ones of equal or higher q u a l i t y .

N O T E : Talking about part substitutions, there are Signature part s upgrade kits available for the SET-300B. These upgrade kits re p l a c e components in the signal path, input wiring, power supply filter caps, coupling caps, the addition of film bypass caps, and vibration/isolation components. (see page 25 for details)

The parts for your Assemblage kit have been packaged into several g roups: capacitors, resistors, semi-conductors, and hard w a re. Each component type is individually packaged to allow for ease of identification.

The process of stuffing the main board with parts is in fact a re l a t i v e l y simple pro c e d u re - Generally the sequence will be to simply obtain the bag containing the appropriate part, carefully bend the leads, place the part into the holes in the PC board, then solder and trim the leads. (Please review our soldering instructions on the next page).

Soldering:

Let it be said once, to get it out of the way - all soldering must be done with rosin core solder! There is no warranty on equipment in which acid core solder has been used. Please use the silver solder p rovided in the kit.

Wire Stripping:

Unless otherwise instructed elsewhere in this manual, the norm a l p ro c e d u re to ‘pre p a re’ a cut wire is as follows;

q Trim or cut the wire to the desired length. q Strip back the wire jacket 3/16”(~5mm), to expose the wire inside.

Use your favorite tool, the knife or wire strippers. If you are using the knife, please be careful and read the instructions on the following p a g e .

q Twist the wire strands to gather them together and then solder them.

This is called the ‘tinning pro c e s s ’ .

Mechanical Assembly:

The SET-300B has been designed with ease of assembly in mind. To this extent, the chassis has been designed with built-in standoffs, to which the PC boards are attached. This allows the PC boards to be easily installed and re m o v e d .

T h e re is a minimum of wiring involved in putting this kit together generally the power transformer must be wired to the PC boards, the output transformers connect to the speaker binding posts and the 300B sockets dire c t l y, and the IEC socket connects the power t r a n s f o rmer and AC switch board. The Mute switch and the input (I/P), RCA jacks are wired to the Main PC board .

We will leave most wiring until the last few steps, as we will first c o n c e rn ourselves with correctly placing and soldering all the components to the PC board s .

Please be sure to follow the installation instructions closely, because some important mounting details etc. may be included in any step.

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Wire Stripping with a Knife

If you own a wire stripper, we’re assuming you know how to use it. If not, and you are new to the world of audio construction, you can use a hobby knife to do the same job. Simply cut around the insulation leaving an appropriate length for the lead, be very

Soldering

• If a lead bender is not being used, hold the component (resistor, capacitor, LED,...) with a pair of needle nose pliers and bend the leads to the appropriate width so it can fit through the donut pads in its position on the circuit board.

• DO NOT bend the leads by applying pressure to the component, bend by pushing directly on the lead. Bend only as in the picture, this will make it easier to remove the parts from the PCB in the event that you may want to upgrade the part later, without removing the PCB from the chassis.

• Position the component on the circuit board and hold it in position as you bend the leads out.

• To help conduct the heat from the soldering iron, “tin” the tip of iron by applying a touch of solder to the already heated iron tip.

careful to cut only the insulator and not the wire itself. Pull the excess insulation away and you have your lead. If the wire is made of strands, twist the lead between your fingertips to keep it from fraying.

• Push the soldering iron tip against the lead and the foil donut pad on the circuit board and hold for 2 seconds.

• Then apply the solder to the other side of lead, also touching the donut pad. Let the heated lead and pad melt the solder, the lead.

• Remove the iron and solder and let the connection cool. Trim off the excess lead.

• NOTE: When done C O R R E C T LY, by heating the lead and foil donut pad simultaneously, the solder should flow o u t w a rd, gradually blending from the lead to the foil.

• When done I NC O R R E C T LY, by just heating the foil pad and not the lead, a hard rosin bead will surround the lead, insulating it from the connection.

• An I NC O R R E C T solder joint is also done by just heating the lead and not the foil pad. Here a hard rosin bead form s on the pad, insulating it from the lead.

• To correct these unacceptable solder joints reheat and if n e c e s s a ry apply a little more solder.

not the iron tip. The solder should flow aro u n d

Solder Bridges - solder bridges usually happen when too much solder is used, or the solder is dragged from one connection to another when heat is applied. If a bridge develops, turn the circuit board upside down and reheat the connection, allowing the solder to flow onto the iron tip. Then resolder the connections as before, being careful that just enough solder is used to make a c o n n e c t i o n .

• H I N T: It is handy to keep a damp sponge nearby to clean the iro n ’s tip after each joint is completed.

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Assembled PC Boards

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Main PC Board Parts Placement Guide

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Assembly Instructions

PC Board Preparations:

I know that you are more than ready to go, so lets start off by pre p a r i n g the printed circuit boards, (PCB’s ) .

Locate the “panelized” PCB and break them apart by twisting the board or cutting at the bridging tabs, producing 5 separate printed circ u i t b o a rd s .

The 5 boards are as follows;

q Main PCB (the largest one), q Left CH Filter Bank, q Main Filter Bank, q AC SW PCB, q Right CH Filter Bank.

Using your file - debur the edges of all the boards where the bridging tabs have left a jagged broken edge.

Then get ready to really start the assembly of your new SET- 3 0 0 B a m p l i f i e r. This is where you create those plumes of solder resin smoke, which seems to lull you into your own private world. You know that entrancing state that your mind invariably takes you to when you dwell so deeply into the concentration of building something with your own hands... Let these thoughts flow through your mind now, turn on your soldering iron, and here we go!

PC Board Stuffing:

Please note that with the exception of the tube sockets and their s t a n d o ffs, all components mount on the silk-screened side of any of the PC boards. Outlines for components are silk-screened on the PC board to aid in the part identification and to facilitate the correct placement of the components. Remember that the re f e rence designators are also included in the Parts List on page 4.

Following the stuffing sequence guide below, you simply obtain the bag containing the appropriate part, carefully bend the leads, place them into the holes in the PC board, and solder into place. Trim the leads from the rear side and that is it! Repeat this process several times, and the b o a rds will be stuffed. Assembly proceeds in this ord e r.

Rectifier Diodes & Bridges:

Ve ry import a n t : the band on the diodes must correspond to the band on the diode outline on the PC board .

q D1,2 LD1,2 S F 4 0 0 7

Installing these Bridge Rectifiers correctly add an extra challenge, are you up to it? CUE: Look for the “+” sign on the part to align with the PCB m a r k i n g s .

q BR100, LBR100 TL400G

(Keep these cut leads they will be used later. )

q BR400 R B 1 5 1

Resistors:

I m p o rtant: Resistors identified with an asterisk “*” should be raised off the PC board surface by approximately 3/16” (or 4mm), in order to aid heat dissipation of that part .

Resistors: (Keep some of these small resistor leads for later use.)

q R1, LR1 100K Holco (Black w/white lettering) q R2, LR2 1K (Sig) q R3, LR3 475R (Sig) q R5,8, LR5,8 100R Holco (Black w/white lettering) (Sig) q R10, LR10 249K (Sig) q R11,12, LR11,12 100R Metal Film (coloured stripes) q R301,302, R400,401 100R Metal Film (coloured stripes) q RF1 1 K 2 q VR1, LVR1 200R Trimpot - (Tu rn the trimmer pots to

their center position if they are not there alre a d y. )

Next these are all - raised above PCB 3/16” (4mm)!

q R4, LR4 33K 2W* (Sig) q R209A, B, LR209A, B 68K 2W* On Left & Right CH Filter Banks q R300 100K 2W* q R210, LR210 150K 2W* On Left & Right CH Filter Banks q R205A,B, R206A,B 220K 2W* On Main Filter Bank q R208A,B, LR208A,B 220K 2W* On Left & Right CH Filter Banks q R6, LR6 10K 3W* (Sig) q R200, R201, R202, R203 5R6 3W* q R13, R13A, LR13, LR13A 3K9 5W* q R13, B, C, LR13,B, C 3K 5W* q R7, LR7 10K 5W* q R207, LR207 1K 5W* On Left & Right CH Filter Banks q R402, 9B, LR9A, B 15K 5W* q R100,101 LR100,101 .56R 5W*

8-Pin Tube Socket Installation on the Main PCB:

As noted above, all of the tube sockets will be mounted on the rear side of the Main PCB. (The side with no white silk-screening on it). Notice the labeling on the PCB -”REAR SIDE SOCKET”.

You will need to gather these part s :

q 8 Pin PCB Mount Octal Sockets x5 q 4-40 x 1/4” Philips scre w, Pan head x 2 0 q #4 Internal tooth lock washer x 1 0 q 4-40 1/2” Hex. Aluminum Stand-off x 1 0

q As a sub-assembly, loosely screw the standoff’s to each of the octal

sockets using the 4-40 screws, (no washers used here). The 2 standoff’s point in the same direction as the socket pins.

Note that there is only ONE electrically correct orientation for these 8-pin sockets when placed into the PC board. Each socket has a central hole with a notch groove. This is the indexing keyway, which must line up with the silk-screen outline on the topside of the PC board .

q Now place the socket assemblies in their appropriate locations - do not

solder yet!

q F rom the component side, secure the socket sub-assembly to the PCB

with the 4-40 screws and #4 lock washers.

q Tighten up the screws to hold the tube sockets securely to the stand-

o ffs. You may need to hold the standoff’s secure as you tighten the s c re w s .

q Check again that the tube sockets are aligned pro p e r l y. Now is the

time to solder the socket pins to the PCB.

q Once the sockets have been soldered to the PC board, the ends of the

pins can be trimmed.

Capacitors - Electrolytic:

Did you know that electrolytic caps are polarity sensitive? Yes they are , and do you know what happens to them if you put them in backward s ? Nothing, not until you apply power to them that is, then they BLOW UP in a big puff of smoke!!! No kidding, so please take note of the picture that shows the cap polarity. Look at the caps, the NEGATIVE leads or t e rminals are all marked with a large wide band with a negative sign in it. This then means that the opposite lead or terminal will be the POSITIVE one. Align the Positive with the “+” sign on the PCB. Get this wrong and your neighbours may end up knowing about it when they see the smoke signals emanating from your work shop window.

–

1112

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q C1, LC1 470uF 16V (Sig) q C2, LC2 220uF 160V q C4, LC4 100uF 100V (Sig) q C5,6, LC5,6, 10uF 450V q C300 10uF 450V q C100,101, LC100,101, 4700uF 16V (Sig) q C400 4700uF 16V q C200A,B 100uF 400V On Main Filter Bank q C201A,B 470uF 400V On Main Filter Bank q C202A,B, LC202A,B 220uF 400V On Left & Right CH Filter Banks

Capacitors - Film, etc.:

q CC1,2,3 .1uF 50V q C3, LC3 .22uF 600V *** Keep these cut leads for

later use *** (Sig)

q AC1 .1uF 275VAC On AC SW PCB

Switch:

q SW1 DPST Push-On Push-Off switch for AC SW PCB

Miscellaneous Parts:

Wiring:

F rom the backside of the PC board, filament power needs to be j u m p e red over to V1 from V3. Note the pair of enclosed pads that are just above the two tube sockets. Look for the markings labeled “A >”, and “< A”. These pairs of pads need to be connected together with the green wires, and you need not worry about the polarity because this is an AC filament voltage.

q G reen 18awg 7.75” (200mm) x 2 q Cut 2 pieces of 18awg Green wire 7.75” (200mm) long and ‘pre p a re ’

both ends for soldering.

q F rom the back of the PC board, insert and solder the pair of wire s

into the empty pair of pads at V1.

q Twist these wires tightly together to take up the slack and then insert

the free ends into the pair of pads closest to V3.

N o t e : Do not thread this wire between the tube socket standoff and its pins. The tube input grid pin 1 is too close for comfort here .

q As you solder these into place check that you put them into the

g rouped pads labeled “<A”.

q F rom the top of the PCB, trim the excess wires at both V1 and V3.

LED Indicator Light:

Because the distance from the PC board to the mounting hole in the f ront of the main chassis/faceplate is greater than the length of the LED leads, wire extensions must be soldered to the LED leads. Use two resistor leads left over from the installation of the resistors. Tw o 1”(25mm) lengths are sufficient. Heat shrink tubing is then used to cover and isolate the leads from any chance of a short circuit. This is v e ry important because the LED is supplied by the V1 & V3 filament s u p p l y , which is biased up to a high DC voltage potential, which saves the tube cathode from self-destruction. Then the LED leads are bent to enable it to be mounted into the front panel hole.

q LED1 Coool Blue LED power indicator x 1 q cut leads x 2 q 1/8” heatshrink tubing 1 5/8”(42mm) x 2 q Attach the two extension leads to the LED leads by first holding the

LED leads with a pair of needle nose pliers. See the photo please.

This is very important to do because the heat being applied while soldering on the extensions can easily destroy the LED! We need to keep this ‘coool blue’ LED cool!

The total lead length needs to be at least 1 7/8” (47mm) long.

q Cut 2 pieces of 1/8” heatshrink tubing 1 5/8”(42mm) long. q Slide the heatshrink tubing over the LED leads up to the LED body

and shrink it into place by heating the tubing with the soldering iron or a hot air gun.

q Next we will bend the LED at a right angle according to the picture .

Pay close attention to the flat side of the LED body. LED’s are polarity demanding. Align the LED flat side with the PCB screening. If your LED does not have a flat side, then be sure that the long lead, or the ANODE, connects to the round pad on the PCB, or the pad labeled “ A ” .

/1 6”

17/1 6”

q Put the LED aside for now because it will be easier to mount it later

after the PCB is installed.

This now completes the soldering of the PC boards. Just before you take a break and admire your handy work... Go back and doublecheck all your work. You know, look for the presence of solder bridges, cold solder joints or missed solder joints, stray pieces of wire, leads not trimmed, and check that all components are inserted corre c t l y with re g a rds to polarity.

This is a good time to sample your favorite re f reshments or get some f resh air.

Bottom Cover & Main Chassis Assembly:

Welcome back. Next we will work on mounting of the feet, IEC socket, RCA jacks, speaker binding posts, mute switch, and whatever other p a rts or components that I can’t think of now that needs to assemble to the chassis itself at this time.

Anxious to get going I know, but lets protect your investment a bit first. Clean your work area from any foreign objects that may scratch the chassis or transformers while they are on their back. You may want to place a soft cloth or towel on your working surface to provide a safe padded working enviro n m e n t .

Bottom Cover Feet:

This simple step will get us off to a running start you might say. The four rubber feet can now be fitted to the cover for the bottom of the c h a s s i s .

q Rubber Feet x 4 (Sig) q 6-32 x 3/4” Philips screws x 4

Using the 6-32 3/4” screws, bolt the feet in place in each corner of the bottom cover. CUE: The feet will lie flat or will be flush to the surf a c e of the cover when mounted corre c t l y.

q Put this cover aside for now we will need it later.

Main Chassis:

Place the chassis right-side-up in front of you on your clean scratchp roofed surf a c e .

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Transformer Removal:

B e f o re proceeding any furt h e r, remove the transformers from the chassis. This may make life a whole lot easier and avoid the chance of damaging or scratching the transformers.

Why remove them you say, are n ’t we trying to assemble this thing? Ye s we are but for one, they may be in backwards, and they will get in our way for now. So out they come.

q U n s c rew the screws holding the transformers in place - remove the

output transformers first! Then the power transformer can be removed. Set all the transformers aside where they won’t get in the w a y, we will, actually you will reinstall them later.

Now we may place the chassis up-side-down in front of you, again on your clean scratch-proofed surf a c e .

Choke Inductor:

Still in the mood for disassembly? Guess what gets removed now? If you guessed the power supply filter choke, you where right. Do so and put it aside for later. Put the nuts and screws in a safe place as w e l l .

Speaker Binding Posts:

Install the speaker binding posts, (yes I did say install), such that the red post lines up with the “+” screening on the rear of the chassis, or t o w a rds the top of the chassis, and the black post lines up with the “-” screening on the rear of the chassis. Use the supplied washers and nuts, and ensure that the posts are attached tightly to the chassis. (5/16” nutdriver) NOTE: Be aware that the individual post itself sits into a key-way in its mounting housing.

q Dual 5-way Binding Posts x 2 (Sig)

Be pre p a red, we are now entering into some of the more delicate assembly pro c e d u res involved with this SET-300B construction kit.

300B Tube Sockets:

H e re is an easy warm-up to what is to come. The 300B tube sockets a re to be correctly oriented, mounted to the chassis openings. The nylon shoulder washer will cushion the ceramic socket from the abrasive and crushing kepnut.

q Ceramic wafer socket x 2 q #6 nylon washer x 4 q #6 Kepnut x 4

q View the top of the socket and notice that all the pin access holes are

NOT all the same size. There is a pair of large and small holes.

q Slide the socket over the two mounting studs flanking the two larg e s t

chassis cutouts.

Be sure that the largest pair of socket holes are to the rear of the chassis! Please be sure to get this correct, because there are no other pin identifications on this ceramic wafer socket.

q Install the nylon washers over the studs, and then the #6-32 k e p n u t s .

q Snug up the nuts, there is little chance that the socket will be

damaged, because of the compliant nature of the nylon washers.

q To pre p a re the socket pins for the installation of the Main PC board ,

we will now bend the solder lugs of these terminals inward toward the center of the socket. See the photo for the finished look. CUE: Place the MAIN PCB over the socket to see if the socket pins clear the edges of the circuit board cutout.

q Repeat this pro c e d u re for the other 300B socket.

B e f o re A f t e r

RCAInput Jacks:

Install the RCA jacks, making sure that the insulating washers are c o rrectly saddled within the chassis holes. The solder lugs will need to be positioned properly for future connections and likewise for the

jack.

Right I/P

q RCA female jack with RED band x 1 (Sig)

q Red is for the Right channel I/P. Note the screening label “R” on the

chassis rear panel, indicating the Right channel I/P.

q F rom the inside working outwards, place the solder lug on the jack,

then the nylon shoulder washer.

q Place these into the chassis hole from the re a r.

q Apply the flat nylon washer and then the nut from the outside.

(12mm nutdriver or wre n c h )

q Notice that the RCA jack signal terminal is notched. Align this notch

to face upwards towards you and while tightening the nut hold the solder lug so that it points straight over to the opposite RCA jack.

q One more finer detail, bend the solder lug out to 45 degrees fro m

the chassis. Check out the photo to ensure you get a clear picture of this setup. You will be soldering to this lug later and we need good access to it and this will also help to ensure that the wire lead mounting into this hole will not come in contact with the rear chassis.

Left I/P

q RCA female jack with WHITE band x 1 (Sig)

q White is for the Left channel, I am sure you know where this one

goes, go for it.

q This time the solder lug again points towards the opposite RCA jack

RED

WHITE

Mute Switch:

Having a mute switch is one of the nice features of this kit. The vert i c a l

travel of the long bat handle makes it easy to access from the fro n t

and unmistakable as to what position the control is in (Up for Mute, and Down for Operate).

q DPDT toggle switch x 1

q The switch mounts from the inside of the chassis along with the

indexing or anti-spin washer. Note that this washer also has a keying position tab that must fit into the hole provided in the chassis.

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q F rom the rear side of the chassis screw on the switch nut using a

5/16” nut-driver, lightly tighten it. Installation of the lock washer is optional. These switches can be delicate, be careful not to over tighten the nut. Also note that the switch can be knocked and damaged if you are not careful while handling the chassis.

RCAJack to Mute Switch Wiring:

H e re is where your nimble little fingers will give you an edge over the next guy. If you are a practicing brain surgeon or the S.W. A . T. team bomb specialist, or simply an accomplished needle nose master, you may find these next few steps entertaining. For the rest of you, just take your time, what’s the hurry, I have not been timing you.

q Take a good look at the photo of these wired components and start

by taking one of the cut resistor leads and connecting it to one of the eyelets of the RCA jack solder lugs.

q Crimp the lead into position through the hole on the RCA solder

l u g .

q Do not solder it into position yet. The signal common wire needs to

be inserted into this hole later.

q Do the same on the opposite RCA solder lug.

q Bring these two leads together onto the center terminals of the Mute

switch, bridging the left and right center switch terminals together as well. Trim the length of the leads as necessary.

q C a refully solder these center terminals of the Mute switch to the two

g round leads.

q Find two more cut leads long enough to fit between the RCA center

signal pin and the top lug on the Mute switch. See the photo as n e c e s s a ry.

q One end of these leads wraps around the Mute switch top term i n a l

lug closest to its adjacent RCA I/P jack, and the other end is then i n s e rted into that RCA jack center pin hole.

q Repeat this for the opposite channel.

q At this time solder the leads at the Mute switch only.

Chassis Solder Lug:

The single point chassis ground for this amplifier is located dire c t l y between the RCA jacks and above the Mute switch, on the inside of the chassis. If there is paint on the standoff top, it must be re m o v e d . This is a good time to ensure that all chassis ground connection point s t a n d o ffs are free of paint. Note the 4 diff e rent standoff locations to check for unwanted paint.

q Shielded 4 Conductor Input x 24” (710mm) (Sig)

Signal cable

q 3/16” Heatshrink tubing 1/2” (13mm) x 1

q Check that this cable is no longer than 28” (710mm) q On one end of the cable, to be dubbed ‘the long end’, remove 1.5”

(38mm) of the outer insulating jacket. This is the signal input end of the wire .

q On the other end of the cable, to be dubbed ‘the short end’, re m o v e

1.25” (32mm) of the outer insulating jacket.

q With a sharp fine tip equipped utensil like a safety pin, care f u l l y

unbraid the outer braided shield of this cable. Use the tip to methodically comb back one braid bundle at a time. Settle back in a c o m f o rtable chair because will take 5-10 minutes each end to do.

q Do the same on the opposite end. q Once you have unbraided the shields back to the jacket, on the

‘long end’ straighten and twist the shield wire into a nice single conductor and cut it to 1” (25mm) in length. Tin this end.

q On ‘the short end’ we do not need the shield at all. Please trim it right

back to the outer jacket.

q At both ends, trim off the cotton filler material with your side cutters. q Notice the colour coding of the 4 conductors. 1 pair has solid

colours and the other is not, it has a stripe. Twist into like pairs and p re p a re and tin the ends by stripping off the standard 1/8” (32mm) of the wires’ jackets.

N o t e : These conductors are not tin plated copper wire so you must be sure to tin the ends thoro u g h l y. The conductor jacket is polyethylene so it can take the heat.

q Basically we now have a blue and a white wire in each twisted pair.

For clarification, we will use the SOLID Blue and White wires as the Left channel, and the Blue wire will be the signal common for this pair.

q The first connection to make with ‘the long end’, will be the Solid

Blue wire to the Left channel RCA jack solder lug (this is the jack to your right). Simply slide this Solid Blue wire into the open solder lug hole and solder both conductors into place.

q Do the same on the Right channel connecting the Blue w/white

stripe wire to the Right RCA solder lug hole.

q To connect the remaining White wires, try to maintain the twisted pair

and position the wires into the holes of their respective RCA signal input pins.

q Solder these connections to the RCA jacks. q Almost there, one more connection to make. That would be... to

connect the shield wire. Not sleeping I hope.

q Locate the chassis solder lug and notice that nice larg e

accommodating hole just waiting to be used. Solder the shield into this position.

q Finally we will dress this cable by sliding a 1/2” (13mm) piece of

3/16” shrink tubing onto the cable from the free end. Slide it over the exposed shield and wires as far as you can neatly do, then shrink into p o s i t i o n .

q Te m p o r a r i l y, you may want to tape this cable to the inside of the

chassis along its walls to the right side and then the front. This will keep it out of harms way, not to mention testing your patience.

q solder lug q #6-32 1/4” zinc scre w q If this standoff has no paint on its top surface, mount the solder lug

using a #6-32 1/4” zinc screw and bend the lug out to be like the p h o t o .

q Next, using one more cut resistor lead, wrap one end to the solder

lug on the chassis standoff. The other end connects to the center of the ground connections made on the Mute Switch (center pins).

q Solder the connection at the Mute Switch only at this time.

Input wiring:

M o re fun to come doc’. We are now going to pre p a re both ends of the Signal I/P cable and attach one end to the RCA jacks.

Well, was the operation a success? I hope so, because we are not going back in.

IEC - AC Power Socket:

The IEC socket is the next component to be installed. I am sure that you know that this is where the AC power cord is connected, but this is also where the main power fuse is housed. Notice the small sliding drawer below the receptacle opening, on the front side. You may even notice that the fuse drawer will not open if the power cord is installed! We will need to pre p a re and attach a few wires to this IEC socket b e f o re we install it into the chassis, so here we go.

q Black 18awg 4”(100mm) x 1 wire ‘A’ q Black 18awg 2”(50mm) x 1 wire ‘C’ q G reen 18awg 2.5”(64mm) x 1 wire ‘B’ q Heat-shrink tubing 1/8” .5” (13mm) x 3 q IEC Socket x 1 q M3 10mm (3/8”) Blk CS screws x 2

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q M3 10mm (3/8”) Blk CS screws x 2 q Solder lug x 1 q 6-32 1/4” Zinc Philips screw x 1

< I n s e rt IEC wired photo>

q P re p a re the list of wires and heatshrink tubing to the lengths above.

P re p a re the wire this time by stripping 1/4” (6.5mm) of the jacket off the ends.

q Following the photo captions, attach the Black wires ‘A’ and the

G reen wire ‘B’ to the terminals labeled ‘L’ and the center bottom t e rminal, the ground, re s p e c t i v e l y.

G ro u n d wire B G r e e n

Live wire A B l a ck

Link wire C B l a ck

N e u t r a l

q Try to insert the wires into the holes in the IEC terminals and crimp

or wrap the wire around the terminal before soldering.

q Slide the heatshrink tubing onto the black wire only and shrink it over

the term i n a l .

q The 2” black wire is used to link the fuse terminal to the “L” term i n a l

on the back of the IEC module. Slide two pieces of heat shrink tubing on the link, 1 for each end. The “L” terminal now becomes the bottom left terminal in this Photo.

q F rom the outside, install the IEC module into the chassis with the

fuse drawer towards the bottom of the chassis.

q Simply bolt in place using the supplied M3 scre w s . q Next screw the solder lug to the chassis standoff next to the IEC

module.

q The green wire from the IEC module will be soldered to this lug now.

No heatshrink tubing is to be used on this connection. Loop the wire t h rough the solder lug hole, crimp and solder.

Main Chassis Assembly

Now we can start mounting and connecting the remaining hard w a re like the choke, transformers and the PC boards, and finish off the re q u i red wiring. Lets transform this basic black pizza box into an a m p l i f i e r !

Choke Mounting:

In the main power supply of this 300B amplifier we use a choke or inductor plus capacitors in a pi filter arrangement. This AC ripple filter works very efficiently in purifying the high voltage. This Choke is mounted inside of the chassis. We will also pre p a re the leads for easy installation to the Main Filter Bank PC board .

q #8-32 1/2” Philips screws x 2 q #8-32 kepnuts x 2 q 4H Choke Inductor x 1

q B e f o re you jump the gun and install this piece of iron, we will dre s s

the leads. Tightly twist the black and white wires and trim them to 4.5” (115mm) long and tin the ends.

q Relocate the choke mounting hard w a re that you put aside (#8 nuts

and screws), and relocate the two mounting holes in the center rear of the chassis.

q OK now the choke is installed such that the wires exiting its end bell

a re facing towards the left side or the IEC module.

q I n s e rt the screws from the outside of the chassis, and tighten down

the kepnuts for the inductor into position with an 11/32” nut-driver while holding the head of the screw with a Philips scre w d r i v e r.

Power Transformer Mounting:

The custom power transformer is the single transformer with the most w i res coming out of it. It is mounted from the top of the chassis and it needs to be properly oriented. Once installed all the primary and s e c o n d a ry wires will be cut and groomed to be neat as possible.

q Power Tr a n s f o r mer x 1 q #10-32 3/8” Blk Philips x 4 q #10 Split lock washers x 4

q Now that you have such a nice clean soft working surface, lets test

it out. Check for any foreign materials that may cause scratches to the chassis top surface.

q For greater ease of this next assembly sequence, flip the chassis

over onto its right-side-up position. No kidding you say.

q We need to arrange this transformer position so that the primary

winding wires coloured, brown, orange, white, and black, etc., all face t o w a rds the RIGHT Channel or the IEC module.

q With this relationship in mind, gently place the transformer on its

side on top of the chassis, on top of where the tube sockets will be.

q Feed the Primary and Secondary wires down through the larg e

access holes into the chassis cavity. Lift the transformer up and onto its mounting location when you have fed enough of the wires thro u g h to allow this to happen. CUE: Watch out for pinched wire s !

q Using the #10-32 screws and lock washers, secure the power

t r a n s f o rmer to the top of the chassis.

Output Transformer Mounting:

The custom output transformer pair is also mounted from the top of the chassis and they need to be properly oriented as well.

q #10-32 3/8” Blk Philips x 8 q #10 Split lock washers x 8 q Output Tr a n s f o rmers x 2

q We need to arrange these transformers’ position so that the primary

winding wires coloured red and blue are entering the access holes closest to the front of the chassis.

q While holding the O/P transformer above its mounting position, feed

the wires down into the appropriate access holes and then place the t r a n s f o rmer down onto the chassis.

q Using the #10-32 screws and lock washers, secure both of the O/P

t r a n s f o rmers to the top of the chassis.

This is now the end of the grunting section. Chassis assembly is always involving the heavy work. Lets put aside our macho bro n z e and re-apply our brains.

A quick check of what we have just installed would be in order now. It is easy to correct anything at this stage; no E.C.N.’s needed here . Check the following:

q A re the SPEAKER BINDING POSTS arranged with the RED term i n a l

t o w a rds the TOP of the chassis, or away from you? A little “+” sign will also be adjacent to this RED post.

q Is the IEC AC input module positioned such that the green wire is

away from you closer to the TOP of the chassis, which ‘looks like’ the bottom from here ?

q The POWER TRANSFORMER RED wires need to be to the RIGHT

side of center.

q The OUTPUT TRANSFORMER secondary end with the bundle of six

(6) wires must be to the REAR of the chassis.

q A re the wires from the CHOKE on the LEFT side?

Good work, lets move on. That is of course that you are ready for the, ‘not difficult’, but demanding task of correctly wiring this amplifier.

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Chassis Wiring (Part 1):

In this section we will connect the output transformers and set the O/P load impedance to 4,8, or 16 Ohms, configure the power transform e r’s p r i m a ry windings for your AC line voltage, then connect and install the AC SW PCB.

q Black 18awg hookup wire 10.5” (267mm) long x 1

(For Stereo configuration)

q Black 18awg hookup wire 11.5” (292mm) long x 1

(For Mono Block configuration)

q Black 18awg hookup wire 1 2” (305mm) long x 1 q 3” Cable Ties x 2 q Twist style Connector x 4

Output Transformer Wiring/Configuration:

First the 300B plate connection to the output transformers will be dealt w i t h .

q The RED wire from the transformers need to be trimmed to a length

of 5.75”(146mm) measured from the chassis opening.

q Strip this silver-plated copper, teflon jacketed leads to 1/4” (6.5mm). q Looking from the top of the 300B tube socket, attach this RED lead

to the bottom right pin. CUE: Look for the right hand small hole in the socket which is the closest to you as you are working from the front of the chassis. Wrap and crimp the wire into place and then solder. Do both channel sockets the same way. Please check the photo for p roper pin ID if in doubt, this socket does not have pin numbers on it to aid you here .

red wire f rom output t r a n s fo r m e r

l a rge holes

small holes

The following blue wires are the high voltage connections for the output transformer and there f o re the 300B’s. These will be connected to the Main Filter Bank at a later time, but we will get them ready now. Note that each wire is a diff e rent length, if you wish it to be.

q P re p a re the BLUE wire of the LEFT CHANNEL O/P, which is the

Right side as you are looking at it from the top, to a length of 7 1/4” (185mm).

q Now pre p a re the other BLUE wire for the RIGHT CHANNEL, which

is the Left side as you are looking at it from the top, to a length of 5” (127mm). For all of you really fussy D.I.Y. e r’s, make this wire the same length as the left channel, (7 1/4”). I have tried to keep perf e c t s y m m e t ry wherever possible in this design.

Mono Block operation or Stereo operation?

Two B or not two B, that is the question. The option is yours, do you want two SET- 3 0 0 B ’s per channel driving your speaker cabinet, or do you want one SET-300B per channel to drive your speaker cabinet? To put it another way, do you want a Mono Block setup with 16 watts of power for your one speaker cabinet, where you will need two amp c h a s s i s ’ s for stereo, or are you going to run a single Stereo amplifier chassis with 8 watts O/P per channel, to drive your pair of speaker c a b i n e t s ? Hence, if you are running the standard Stereo chassis skip down to the heading - ‘Stereo Operation’.

Mono Block Operation:

Now here is a feature that will make some of you very happy! For those of you who would prefer to run your SET-300B as a mono block, this next setup is for you. (Remember of course, that for a stereo or multichannel setup you do need a SET-300B mono block for each audio channel running.) The power increases from 8 watts to 16 watts in this mode as well. The format here is that we will connect the two audio channels together at the input and apply your input signal to either I/P RCA jack. The doubling of power will be developed by configuring the output

t r a n s f o rmer windings in series with each other. The speaker will then be connected from the ‘-’ of the Right channel speaker post, to the ‘+’ of the Left channel speaker post. One last point to consider - if you want your output speaker impedance set to 8 ohms, the two individual t r a n s f o rmer windings need to be set for 4 ohms operation. Eight ohm t r a n s f o rmer setup is there f o re needed if your speakers are 16 ohm i m p e d a n c e . A permanent signal common re t u rn wire must be connected to the “-” speaker binding post of the Right channel and another that i n t e rconnects the “+” post of the Right channel to the “-” post of the Left channel before the transformer secondary wires are attached. When reconfiguring for diff e rent speaker loads, you will not be changing these connections.

q Cut and pre p a re one 12”(305mm) length of Black 18awg hookup

w i re. One end treated as per the usual and the other gets stripped to 3/4” (19mm), tin them both.

q Cut and pre p a re one 11.5” (292mm) length of Black 18awg hookup

w i re. Both ends gets stripped to 3/4” (19mm), tin them both.

q I hope that your soldering iron is good and hot because it will need

to be to connect these wires to the terminals of the speaker posts.

q READ CAREFULLY: In the groove at the end of the “-” speaker post

of the Right channel, the ‘long end’ of this wire is snugly wrapped, then, snugly again back around itself to form an “eyelet” shape. Tw i s t this eyelet so that it is tight. We don’t want this connection to be disturbed in the future when you may want to re c o n f i g u re the O/P for a diff e r ent speaker load. CUE: If you approach the post from the center of the chassis, the wire will line up better for its connection to the center of the Main PC board . Connection of the free end will be left until the Main circuit board is installed into the chassis.

q Connect the 11.5” wire to the “+” post in the same fashion. q The other end of this wire is then similarly connected to the “-”

t e rminal of the Left channel speaker post.

q Lightly tin the “+” speaker post to get it ready for the wire

connections to come.

The next step is to configure the Output transformer secondary windings for the proper speaker load. Remembering what I said above, look below in the ‘Stereo Operation’ section for the wiring configurations for your application, and also follow the ‘General I n s t ructions’ below to make your connections to the binding posts t h e m s e l v e s .

Once this is done please advance down to ‘Chassis Wiring (Part 2)’.

Stereo Operation:

The following construction steps are to be followed if you are using your SET-300B amplifier in a - standard two channel in one chassis or s t e reo chassis operation.

A permanent signal common re t u rn wire must be connected to the “” speaker binding posts before the transformer secondary wires are attached. When reconfiguring for diff e rent speaker loads, you will not be changing this connection.

q Cut and pre p a re one 12”(305mm) and one 10.5” (267mm) lengths

of Black 18awg hookup wire. One end as per the usual and the other gets stripped to 3/4” (19mm), tin them all.

q I hope that your soldering iron is good and hot because it will need

to be to connect these wires to the “-” terminals of the speaker posts.

q The 12” wire will connect to the Left channel “-” binding post, and

the 10.5” wire will connect to the Right channel “-” binding post.

q READ CAREFULLY: In the groove at the end of the “-” speaker post,

the ‘long end’ of this wire is snugly wrapped, then, snugly again back a round itself to form an “eyelet” shape. Twist this eyelet so that it is tight. We don’t want this connection to be disturbed in the future when you may want to re c o n f i g u re the O/P for a diff e rent speaker load. CUE: If you approach the post from the center of the chassis, the wire will line up better for its connection to the center of the Main PC board . Connection of the free end will be left until the Main circuit board is installed into the chassis.

q Lightly tin the “+” speaker posts to get it ready for the wire

connections to come.

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q Now to configure the secondary windings for the desired speaker

load, please first refer to the following chart .

4 Ohm Speaker Impedance

Wi re Colours Connections To

White & Bro w n Spkr + (RED) Black & Gre e n Spkr - (BLK) Blue & Ye l l o w each other with special

twist connector

8 Ohm Speaker Impedance

Wi re Colours Connections To

White & Ye l l o w Spkr + (RED) B l a c k Spkr - (BLK) Blue, Green & Brown each other with special

twist connector

16 Ohm Speaker Impedance

Wi re Colours Connections To

W h i t e Spkr + (RED) B l a c k Spkr - (BLK) Blue & Ye l l o w each other with special

twist connector

G reen & Bro w n each other with special

twist connector

General Instructions:

q Neatly group the wires as they enter the chassis through the access

hole and twist them together into a spiral. If you are a ‘hot shot’ with the drill, go for it. Otherwise use your fingers.

q Trim these leads to a length no longer than 4.5” (113mm), strip the

teflon jacket 3/8” (9.5mm) from all the ends and only tin the wires that will be terminated to one of the speaker binding posts. (See the chart a b o v e ) .

q Use a 3” Cable Tie about 1.5” (38mm) from the end of the wires to

hold the gro u p .

q A c c o rding to the chart above, twist the conductors together and

solder them to the appropriate speaker post. Or if the lead gets connected to another lead and not a binding post terminal, twist them t o g e t h e r , and then use one of the special twist connectors to firm l y hold the wires together. CUE: If you are connecting 3 wires, (i.e. 8 Ohm setup), then use the larger twist connector. You may solder this connection first if you feel uneasy about using this reliable, high-forc e connection device.

Chassis Wiring (Part 2):

Power Transformer:

Input AC Voltage Configuration:

This kit allows you to configure the amplifier to be used with an AC s o u rce ranging from 100VAC to 240VAC. You will choose from one of five diff e r ent nominal voltage settings.

In a nutshell, there are two primary windings in the power transform e r. In a basic parallel connection the transformer will be set for 120VA C nominal line voltage or a slight variation to the theme will allow for a nominal voltage of 100VAC. Expanding on this, if we set the primaries in series, certain combinations will allow operation with 200VA C , 2 2 0 VAC or 240VAC as a nominal input AC voltage.

In this same sequence of instructions you will be connecting and installing the AC SW PCB.

Oh good, I just re m e m b e red that I enjoy preparing these transform e r windings. This is where I use my power drill to spin and twist the wire s together to make very uniform snuggly twisted pairs. It adds that ‘ p rofessional’ look.

Connection of Power Transformer Primary Wi r e s :

q You may go directly to jail... no no, go straight to the section that

describes the setup for your particular AC line voltage. (We’ll see if you did something wrong later and decide your consequences then!)

q 3/16” Heatshrink tubing 1/2” (13mm) x 2 q 1/8” Heatshrink tubing 1” (25mm) x 2 q AC SW PCB x 1 q #6-32 1/4” Philips screws x 2 q #6 lock washers x 2

100V operation:

q Snuggly twist the BLACK and BROWN wires together. q Snuggly twist the WHITE and ORANGE wires together. q Snuggly twist the BLACK/WHT and BROWN/ORG wires together. q P re p a re and trim the BLK/WHT & BRN/ORG pair of wires to 9”

( 2 3 0 m m ) .

q Locate the AC SW PCB, and on it you will see the label “OUT” and

two solder pads.

q I n s e rt the BLK/WHT & BRN/ORG wires into these pads from the top

and solder them from the re a r, trim any excess leads.

q Trim the WHITE & ORANGE pair of wires to 9” (230mm). Strip 3/8”

(9.5mm), twist together, and lightly tin these wire s .

q Slide a piece of heatshrink tubing onto this pair of wire s . q This pair of WHT & ORG wires are then soldered to the IEC AC

module, to the pin labeled ‘N’ (middle terminal). I know that you will not be able to see this very will so observe the photo.

q Once soldered on, slide the heatshrink tubing over this connection

and shrink it into place.

q Two down and one to go. The last remaining pair do not connect to

anything, not even each other. The truth of it is though, these wires will be live and must be treated with care to prevent an electro c u t i o n .

q On the BLACK & BROWN wires are trimmed to 9” (230mm), more

than cutting off any of the exposed wire lead ends.

q Slide a piece of 1” (25mm) long small heatshrink tubing (1/8”), onto

each wire end, but only half way. Shrink the tubing in place and fold the loose end back against the wire. Take another piece of 1” (25mm) long 3/16” tubing and slide it over BOTH of these wires to couple the ends together.

q You have rolled the dice, please advance down to ‘STICKY Pad

P l a c e m e n t ’ .

120V operation:

q Snuggly twist the WHITE and ORANGE wires together. q Snuggly twist the BLK/WHT and BRN/ORG wires together. q Snuggly twist the BLACK and BROWN wires together. q P re p a re and trim the BLACK & BROWN pair of wires to 9” (230mm). q Locate the AC SW PCB, and on it you will see the label “OUT” and

two solder pads.

q I n s e rt the BLACK & BROWN wires into these pads from the top and

solder them from the re a r, trim any excess leads.

q Trim the WHITE & ORANGE pair of wires to 9” (230mm). Strip 3/8”

(9.5mm) and twist them together and lightly tin these wire s .

q Slide a piece of 1/2” long 3/16” heatshrink tubing onto these wire s .

But don’t let it slide down into the transformer below.

q This pair of WHT & ORG are then soldered to the IEC AC module,

to the pin labeled ‘N’, which is the middle terminal. I know that you will not be able to see this very will so observe the photo at the bottom of this section.

q Once soldered on, slide the heatshrink tubing over this connection

and shrink it into place.

q Two down and one to go. The last remaining pair of BLK/WHT and

BRN/ORG wires do not connect to anything not even each other. The t ruth of it is though, these wires will be live and must be treated with c a re to prevent an electro c u t i o n .

q The BLK/WHT and BRN/ORG wires are trimmed to 9” (230mm),

m o re than cutting off any of the exposed wire lead ends.

q Slide a piece of 1” (25mm) long small heatshrink tubing (1/8”), onto

q You have rolled the dice, please advance down to ‘STICKY Pad

P l a c e m e n t ’ .

1920

Page 20

200V operation:

q Snuggly twist the BLACK and BROWN wires together. q Snuggly twist the WHITE and BRN/ORG wires together. q P re p a re and trim the BLK/WHT wire to 9” (230mm). q Locate the AC SW PCB, and on it you will see the label “OUT” and

two solder pads.

q I n s e rt the BLK/WHT wire into either one of these pads from the top

and solder from the re a r , trim any excess lead.

q Trim the ORANGE wire to 9” (230mm). Strip 3/8” (9.5mm) and lightly

tin this wire .

q Slide a piece of heatshrink tubing onto this wire . q This ORANGE wire is then soldered to the IEC AC module, to the pin

labeled ‘N’ (middle terminal). I know that you will not be able to see this very will so observe the photo.

q Once soldered on, slide the heatshrink tubing over this connection

and shrink it into place.

q The last remaining WHITE & BRN/ORG pair connects to each other.

Trim these wires to 9” (230mm). Strip 3/8” (9.5mm) and lightly tin these w i re s .

q We will make an inline ‘pigtail’ wire termination. Holding the wire s

side by side, twist the two leads together and solder.

q Slide a 1” (25mm) piece of Heatshrink tubing over this connection

half way. Shrink this and fold over the loose end onto itself and apply a 1/2” (13mm) piece of heatshrink tubing over the first one and shrink it again.

q T h ree down and one to go. The last remaining BLACK & BROWN

pair do not connect to anything, not even each other. The truth of it is though, these wires will be live and must be treated with care to p revent an electro c u t i o n .

q On the BLACK & BROWN wires are trimmed to 9” (230mm), more

than cutting off any of the exposed wire lead ends.

q Slide a piece of 1” (25mm) long small heatshrink tubing (1/8”), onto

q You have rolled the dice, please advance down to ‘STICKY Pad

P l a c e m e n t ’ .

220V operation:

q Snuggly twist the BLK/WHT and BROWN wires together. q Snuggly twist the WHITE and BRN/ORG wires together. q P re p a re and trim the BLACK wire to 9” (230mm). q Locate the AC SW PCB, and on it you will see the label “OUT” and

two solder pads.

q I n s e rt the BLACK wire into either one of these pads from the top and

solder from the re a r, trim any excess lead.

q Trim the ORANGE wire to 9” (230mm). Strip 3/8” (9.5mm) and lightly

tin this wire .

q Slide a piece of heatshrink tubing onto this wire . q This ORANGE wire is then soldered to the IEC AC module, to the pin

labeled ‘N’ (middle terminal). I know that you will not be able to see this very will so observe the photo.

q Once soldered on, slide the heatshrink tubing over this

connection and shrink it into place.

q The WHITE & BRN/ORG pair connects to each other. Trim these

w i res to 9” (230mm). Strip 3/8” (9.5mm) and lightly tin these wire s .

q We will make an inline ‘pigtail’ wire termination. Holding the

w i res side by side, twist the two leads together and solder.

q Slide a 1” (25mm) piece of Heatshrink tubing over this

connection half way. Shrink this and fold over the loose end onto itself and apply a 1/2” (13mm) piece of heatshrink tubing over the first one and shrink it again.

q T h ree down and one to go. The last remaining BLACK & BROWN

pair do not connect to anything, not even each other. The truth of it is though, these wires will be live and must be treated with care to p revent an electro c u t i o n .

q On the BLACK & BROWN wires are trimmed to 9” (230mm), more

than cutting off any of the exposed wire lead ends.

q Slide a piece of 1” (25mm) long small heatshrink tubing (1/8”), onto

q You have rolled the dice, please advance down to ‘STICKY Pad

P l a c e m e n t ’ .

240V operation:

q Snuggly twist the WHITE and BROWN wires together. q Snuggly twist the BLK/WHT and BRN/ORG wires together. q P re p a re and trim the BLACK wire to 9” (230mm). q Locate the AC SW PCB, and on it you will see the label “OUT” and

two solder pads.

q I n s e rt the BLACK wire into either one of these pads from the top and

solder from the re a r , trim any excess lead.

q Trim the ORANGE wire to 9” (230mm). Strip 3/8” (9.5mm) and lightly

tin this wire .

q Slide a piece of heatshrink tubing onto this wire . q This ORANGE wire is then soldered to the IEC AC module, to the pin

labeled ‘N’ (middle terminal). I know that you will not be able to see this very will so observe the photo.

q Once soldered on, slide the heatshrink tubing over this connection

and shrink it into place.

q The WHITE & BROWN pair connects to each other. Trim these wire s

to 9” (230mm). Strip 3/8” (9.5mm) and lightly tin these wire s .

q We will make an inline ‘pigtail’ wire termination. Holding the wire s

side by side, twist the two leads together and solder.

q Slide a 1” (25mm) piece of Heatshrink tubing over this connection

half way. Shrink this and fold over the loose end onto itself and apply a 1/2” (13mm) piece of heatshrink tubing over the first one and shrink it again.

q T h ree down and one to go. The last remaining BLK/WHT &

BRN/ORG pair do not connect to anything, not even to each other. The t ruth of it is though, these wires will be live and must be treated with c a re to prevent an electro c u t i o n .

q On the BLK/WHT & BRN/ORG wires are trimmed to 9” (230mm),

m o re than cutting off any of the exposed wire lead ends.

q Slide a piece of heatshrink tubing onto each wire end, but only half

w a y. Shrink the tubing in place and fold the loose end back against the wire. Take a third piece of tubing and slide it over BOTH of these w i res to couple the ends together.

You have rolled the dice, please advance down to ‘STICKY Pad P l a c e m e n t ’ .

G ro u n d wire B G r e e n

Live wire A B l a ck

Link wire C B l a ck

N e u t r a l

AC SW PCB Mounting:

S o rry for the switching around of instructions but we need to mount this AC Switch PC board before going any furt h e r.

q #6-32 1/4” Philips screws x 2 q #6 lock washers x 2

q The lonely Black wire from the IEC ‘L’ terminal (top one), is to be

connected to the solder pad labeled “BLK”. Solder this wire from the back side of the AC SW board, and trim any excess wire .

q F i rmly secure this PCB now to the side panel using the #6 scre w s

and #6 lock washers. CUE: Secure the top screw first. This will hold the PCB in place while struggling to get the lower one installed.

q Good work, more on to ‘Welcome travelers...’.

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STICKY Pad Placement:

Now that you made it here safely I hope, go back one step to AC SW PCB Mounting.

Welcome travelers to my ‘pad’. Please make yourself at home, but first lets tidy up this place shall we.

q Cable Tie Mount Pad x 1 q 3” Cable Ties x 3

q Remove the paper on the back of the Cable Tie Mount Pad to

expose the sticky surf a c e .

q S q u a re l y, stick this tie mount pad to the chassis directly below

w h e re the wires will be routed. Basically half way along the line fro m w h e re the wires exit the chassis access hole to the edge of the chassis. Press it down very firm l y. CUE: Dust the floor of the chassis in this area first.

q G roup these wires neatly, tuck them into place in the corners, or

f o rm them as needed to create a duct-work like effect.

q Slide one of the Cable Ties through the Tie Mount Pad channels and

a round the bundle of wires, mate it and tighten it down. Now using two m o re ties, bundle these wires as you see fit. The photo is a good guide. CUE: The pair of wires with no home, may be folded back along with the bundle and wire tied together.

P re p a re all of these wire sets for soldering, we will need them soon.

Main Filter Bank Connections:

S t a rting here we will be interconnecting all the remaining PCB’s before mounting them to the chassis.

q Black 18awg 3 3/4” (95mm) x 1 q Black 18awg 6” (152mm) x 1 q Black 18awg 6 3/4” (170mm) x 1 q Red 18awg 3” (76mm) x 1 (Sig) q Red 18awg 5” (127mm) x 1 (Sig) q B rown 18awg 6” (165mm) x 2 q Blue 18awg 5” (127mm) x 2

You have done such a great job in preparing all of these wires! So lets put them where they belong. Connecting one wire at a time, start with this one.

q Black 18awg 3 3/4” (95mm) x 1

This wire interconnects the Main Filter Bank power supply common to the Main PCB common. First we will connect one end of this wire to the Main Filter Bank PCB to the pad labeled ‘COM’ which is indicated by the line pointing to the center pad in the common cluster (4 pads consisting of Com, C/T, L, R. CUE: add a few vowels). Connect this w i re from underneath the PCB. The opposite end will be connected s o o n .

Locate these wire s :

q Black 18awg 6” (152mm) x 1 q Red 18awg 5” (127mm) x 1 (Sig)

q Still on the Main Filter Bank PCB connect the above Black wire to

the pad labeled ‘L’ in the common cluster.

q Then connect the above RED wire to the pad labeled ‘LB+1’. Tr i m

the soldered leads.

Just a quickie here to change the pace a bit. A Black Nylon plug needs to be installed into the rear panel hole that is located between the RCA jacks and the Right Speaker binding posts. It just snaps into place. This is where you may install the attenuator so that the amp may be feed directly from your favorite source device.

It is good to see that every one is keeping up with me. Since I am going to take a break now, may I suggest that if you have not taken a b reak yet for awhile, this is a good time to do so as well. See you

l a t e r......and don’t re s t a rt without me, I don’t want to miss anything that

you are doing!

Chassis Wiring (Part 3):

Installation of PC Boards:

Get re a d y , we are on the home stretch. In a few moments we will be p reparing the power transformer secondary winding wires and installing the remaining PCB’s and their interconnecting power supply w i res. As usual, this is not difficult when done in an orderly fashion. Also, when it comes to this part of the construction process of wiring,

it is very important and at times difficult, to keep it neat. As it is my responsibility to guide you through to a result of a professional looking a m p l i f i e r, we will apply a few touches of finesse and you may even end up with a piece of art? Oh boy, there ’s an ego trip. So let’s turn up the music and do the twist!

q Rev up your drill again and snugly twist all the like coloured Power

Tr a n s f o r mer wire pairs together. The RED with YELLOW stripe wire will also be twisted with the pair of RED wire s .

q Once twisted, cut the twisted pairs to the following lengths,

m e a s u red from the chassis access hole outward s :

q RED pr. & RED/YEL 7” (178mm) q YELLOW pr. 6 1/4” (159mm)

q VIOLET pr. 8 (203mm) q G R AY pr. 9 1/4” (235mm) q GREEN pr. 7 1/2” (216mm) q BLUE pr. 11 3/4” (298mm)

Moving on to the Right channel H. V. connections we do the same thing. Locate these wire s .

q Black 18awg 6 3/4” (170mm) x 1 q Red 18awg 3” (76mm) x 1 (Sig)

q Again, from the bottom side on the Main Filter Bank PCB connect

the above Black wire this time to the pad labeled ‘R’ in the common c l u s t e r .

q Then connect the above RED wire to the pad labeled ‘B+1’.

Remember to trim the soldered leads.

Left and Right Filter Bank Connections:

Each channel has its own separate input/driver stage power supply filtering, a dual mono arrangement. This approach helps to furt h e r isolate the most sensitive gain stages. Gather up the Left Filter Bank and the Right Filter Bank PC boards. Next we will connect the B+ w i res that will connect to the Main PCB and then complete the connections to the Main Filter Bank.

q Main Filter PCB x 1 q Left Filter Bank PCB x 1 q Right Filter Bank PCB x 1 q B rown 18awg 6” (165mm) x 2 q Blue 18awg 5” (127mm) x 2

As before, or shall I say, to conform to our style these wires are connected from underneath the PCB’s.

q Connect the two Brown wires to the B+2 and LB+2 pad locations on

the Right and Left Filter Banks.

q Then do the same with the Blue wires connecting them to the B+3

and LB+3 pads on both boards. Trim the excess wire leads above the b o a rd s .

Now complete the connections to the Main Filter Bank - connecting the wiring from the Left and Right Filter Banks to the Main Filter Bank. You will see the obvious wire connections to be made, which are;

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q Connect the RED wires to the pads labeled LB+1 and B+1 on the

flanking L & R Filter Bank PC boards. Repeat the process to connect the Black wires to the LCOM and RCOM from the common c l u s t e r pads ‘L’ and ‘R’.

Wiring to the Main PCB:

At this point, for soldering purposes, you may find it convenient to place all the PCB’s upside down to make the upcoming connections.

q Main PCB x 1 q Using the photo below as a guide, connect the Black wire from the

Main Filter Bank common cluster to the center pad labeled ‘Com’ between the ‘L’ and ‘R’ pads. These pads are located near the center of the Main PCB.

q Connect the LB+2 and B+2 BROWN wires from the Left and Right

Filter Banks to the corresponding pads on the Main PCB.

q Connect the LB+3 and B+3 BLUE wires from the Left and Right

Filter Banks to the corresponding pads on the Main PCB.

q The result needs to look like this photo.

RED

BLK

BLU

GRN

BRNBRN

Power Transformer Wire Routing:

The power transformer has 6 sets of secondary windings, 5 Filament windings and the source of all the high voltages needed in this 300B amplifier design are derived from a single center-tapped high voltage winding. Most of these wires, all but the RED group, will be ro u t e d u n d e rneath the circuit boards and there f o r e soldered from the top of the circuit boards.

g r ay

bl u e

v i o l e t

ye l l ow

g r e e n

q To accomplish this layout it is best to copy what is shown in the

photos above. Sorry for the lack of descriptions but as they say, ‘a p i c t u re is worth a thousand words’, and besides, I don’t feel like typing those thousand words.

q Since the wires are already cut to length, simply form the leads and

tie them off to the chassis standoff’s with the wire ties in the indicated positions and then with my guidance, we will mount the PCB’s. CUE: D o n ’t over-tighten the wire ties, it is not necessary and if you do, you may run the risk of shorting the wire s .

q It looks like you are doing a fine job. Once you have the wires in

place, test the placement of the Main PCB by positioning it into the chassis exactly where it is to be mounted. The tube sockets need to settle down into position in the chassis without interf e rence from any of the wires below it.

Mounting the PCB’s into the Chassis:

Yes we are getting very close now to filling the chassis and fulfilling your dream of building your very own single ended 300B amplifier. The Choke, O/P transformers and Power transformer will all be connected to their PCB’s in this sequence of the construction pro c e s s . #6-32 S/S Philips x 20 #6 Internal Tooth Lock Washers x 2

q Place the set of PCB’s right side up above where they will be mounted. q Tilt the Main Filter Bank towards the Main PCB so that you may gain

access to the pads for mounting the Choke leads from undern e a t h .

q F rom the bottom, insert the CHOKE leads into the pads labeled

‘CH’. Solder from the top and trim the leads.

q Locate the Blue wires from the O/P transformers and plug them into

the rear side of the Main Filter Bank board into their respective pads labeled ‘RO/P’ and ‘LO/P’. Again soldering from the top and trimming the leads.

Now is a good time to connect the RED H.V. wires and RED / YELLOW center tap wire .

q F rom the top of these boards, install the Yellow striped Red wire into

the pad labeled ‘CT’ on the Main Filter Bank PCB, and the Red wire s into the pads labeled ‘RED’ on the Main PCB.

This is where you may need someone to help hold up the Main PCB while you make the underside connections. Someone else’s aid may not be necessary, but why not share some of your inevitable c o n s t ruction success and glory? In any case, you will be connecting the rest of the interconnecting wires from the power transform e r s e c o n d a ry windings.

q While lifting the Main PCB so that you view its under side from the

f ront. Locate the following wires and pad locations and install them in the following ord e r .

1 - Ye l l o w, 2 - Gray, 3 - Blue, 4 - Violet, 5 - Gre e n .

CUE: Look for the text on the bottom of the PCB to help identify the c o rrect wire locations.

q Be sure to always solder from the top of the PCB and to trim the

excess leads when done.

q I trust that all went well. Settle all four PCB’s down and onto their

s t a n d o ff’s. Be sure that there are no wires wedged between any PCB and standoff or between any tube socket and the chassis. The board s will settle into place easily if all is clear.

q Using the #6 screws secure all the PCB’s into position. Note that two

#6 lock washers are used where indicated on the PCB above and below the V2 socket.

A re you saying that it looks like I forgot something? Well I hope not, but maybe your keen eye has picked out the mystery location of one of the few remaining parts of this electronic jigsaw puzzle. There is a 5W resistor that must be mounted - it will straddle both the Main Filter Bank PCB and the Main PCB.

q R(no name) 6R8 5Watt Bridges Main PCB and Main Filter Bank

q Find the 6R8 resistor and solder it into position. CUE: Raise the

resistor above the PCB and keep the lead lengths short enough not to extend too far below the surface of the board. You can not trim them f rom here .

q Connect the BLACK speaker post wires to the main PCB in locations

RC and LC for left and right channels.

G reat work again. You might be saying by now, “Gee it is starting to look like I am done!” Well not quite, but close.

300B Socket Connections:

Next we will connect the 300B tube socket pins to the Main PCB. This is where we use some of the heavy gauge lead clippings from the

Page 23

l a rge bridge rectifiers that you re m e m b e red to keep for this special m o m e n t .

q cut-leads from bridge rectifiers 3/4” (19mm) x 4 q Kimber Kable TCSS Blue hookup wire 1 1/2” (38mm) x 2

q Pick one of the 300B sockets and connect the top two socket pins to

the PCB solder pads labeled ‘H’ for filament heater, immediately above and to the outside of the pins. Solder both ends of this jumper wire .

q Do the same on the other 300B tube socket.

T h e re is one more vacant terminal yet to be connected on the 300B sockets, this is the grid. This is the pin to the bottom left side of the socket closest to you.

q P re p a re the Kimber Kable wires with one end stripped at 1/4”. This

end wraps through the socket pin wire hole and is soldered in place.

q The opposite end then is carefully soldered into the Main PCB where

you will see the label ‘G’ for grid.

q Do the same on the other 300B tube socket.

Signal I/PInterconnect wire installation:

Ok, unless I forgot something, this could be the final soldering task to accomplish in this kit, unless of course you have made some mistakes along the way. Or you are going to wait and install the Signature Upgrade kit after your initial listening tests of this stock unit.

q 3/16” heatshrink tubing 1/2” (13mm) x 1

q H e re is the tricky part, slide a piece of the above heatshrink tubing

onto the free end of the Signal I/P wire .

q P re p a re the four signal conductors as per normal and tin them. q Basically again, we now have a blue and a white wire in each

twisted pair. For clarification, we will use the SOLID Blue and SOLID White wires as the Left channel, and the Blue wire will be the signal common for this pair.

q Solder into place the Blue wires of each pair into the “-” I/P pads as

they are labeled on the PCB.

q Try to wrap the White wire around the Blue wire and then solder it

into the “+” I/P pad.

q Do the same for the other channel. q Finally slide the heatshrink tubing down and over these conductors

as far as possible and shrink it into place.

Faceplate and Button:

Well let’s face it, we have been through a lot together and our a d v e n t u res have almost come to an end. One of the last tasks we have is to mount the Face Plate and to facilitate power switching, we’ll attach the Power Button and Extension Shafts.

q Button x 1 q Faceplate x 1 q 10-32 kepnuts x 2 q Shaft Extensions x 2 q Shaft Couplers x 2 q Coool Blue LED assembly x 1

q N o w, carefully slide the faceplate onto the front of the chassis. q The faceplate can be bolted in place using the two 10-32 kepnuts

and tightened into place with your 3/8” wre n c h .

q C a refully and firmly push the anodized aluminum Button onto one

end of the plastic Extension Shafts and then the shaft into one of the Shaft Couplers. Seat these parts so that they will not fall off or apart .

q Mount the other Shaft Coupler to the power switch itself and

c a refully cut the last Extension Shaft so that when all is assembled, the Power Button is still fully operational while depressing it from the ON position to the OFF position. I am sure that I can trust your best judgement here, remember that trial and error will work here if you do not cut too much off at a time! Take a look around your work area, do you see any orphan part s ?

Have you noticed the Coool Blue LED sitting there somewhere ? Hopefully that is all only one!

q Place the leads into the LED mounting position at the front of the

Main PCB in such a way that the LED body is saddled into the Fro n t Panel LED mounting hole.

q Take a note of how much of the leads go into the circuit board pads.

Trim off any excess that will not be needed to make a good solder connection.

q Solder the LED leads from the top of the Main PCB..... You don’t say!

Now we are done the soldering and now we are done the constru c t i o n of your new Assemblage SET-300B Amplifier! How does it feel? Or better yet, how does it look? “Looks great! But, how does it sound?” you say? OK I know that you are anxious to plug it in, but we must now p e rf o rm the hardest part of this whole construction process...

Final Check and Adjustment:

q 2.5A ‘Slo-Blo’ fuse x 1

(or 1.25A ‘Slo-Blo’ for 220V/240V operation)

q 6SN7 tube x 1 q 6BX7 tubes x 2 q CV378 tubes x 2 q 300B tubes of your choice x 2

Re-examine all wiring to make certain that all the connections are c o rrect. Take your time and check care f u l l y , as correct assembly of your kit is essential for proper and reliable operation. Make sure you check the following points:

q IEC socket wiring: Ground, Live, Neutral q IEC socket to AC SW PC board q IEC socket to power transformer primary q Power transformer B+ (high voltage) wiring to Main PC board . q Output transformer: Blue wire (B+) to Main Filter Bank PC board , q O/P transformer Red wire to 300B tube socket. q Output transformer configuration to speaker binding posts q Main Filter Bank PC board to main PC board: COM, HV+ q RCA jack input wiring - RCA jacks and solder lug q Connections to main PC board q Check all circuit board components and solder joints. q Tu rn the trimmer pots to their center position if they are not there

a l re a d y .

WA R N I N G ! E x t reme caution must be exercised whenever you work in the chassis with the amplifier “ON” and the bottom cover of the chassis is off. - If you must do any soldering inside the chassis for any reason, ensure that the AC power cord is removed and that the amplifier has been “OFF” for at least five minutes. - Never touch or hold the chassis with one hand while probing within the chassis with the other hand! Simultaneous contact at various circuit points under these conditions can result in electric shock with dangerous and possibly lethal voltages.

q Next, turn the amplifier right side up and shake the chassis up and

down and from side to side above your head in order to dislodge any stray wire clippings or solder from inside the chassis. If you can do this, I’d say that I wouldn’t want to get on your bad side or run into you in a dark alley somewhere. Actually don’t do that, all you need to do is set it on its side and give it a few love taps here and there to allow the pieces to fall to the bottom where you can pick it out of the chassis. We need to systematically install the tubes and test the amplifier to minimize any damages due to construction errors or faulty components. If you have a test meter for trouble shooting that will come in handy as well. If you run into problems at any stage of the tube installations please go down to the Trouble Shooting section b e l o w.

q Place the amplifier upside down and facing forw a rds on your

padded working surface. Place a couple of textbooks under the fro n t

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of the amplifier to keep it from tipping forw a rd .

q Now that all the circuit board assembly and wiring has been verified

to be correct, select the 2.5 amp “slo-blo” fuse and install it into the fuse holder. Open the drawer of the IEC AC module and clip it into the back area compartment of the drawer and close it again. For 220/240V operation, use the supplied 1.25A “slo-blo” fuse.

q Make sure the power switch is in the “OFF” position. Plug the

detachable power cord into the AC socket at the back of the amplifier. If you have access to a variable AC transformer (VARIAC), plug the c o rd into it. If not, plug the cord into the nearest AC wall outlet.

q Tu rn the amplifier on. The Coool Blue LED should light. Tu rn OFF the

amp again.

q Select the 6SN7GT and plug it into the center front socket.

q Select the 6BX7GT’s and plug them into the other front sockets.

Each box is identified with a ‘L’ or ‘R’ for Left or Right channel installation. CUE: The chassis is clearly labeled as to which tube goes into each socket.

q Tu rn the amplifier on again. Check that these tubes light up norm a l l y

plus the LED. The 6BX7’s will glow brightly. Tu rn OFF the amplifier a g a i n .

q Plug in the 300B tubes into their sockets and test for a warming of

the tube when you apply power. It may be difficult to see the filaments glowing in these tubes. Tu rn OFF the amplifier again.

q Lastly install the CV378’s. These are the high voltage rectifiers so

please be aware that now after about 20-30 seconds there may be f i reworks in your faulty amp or if not that, there will be dangero u s l y high voltages inside the chassis on all the circuit boards. Keep your fingers to yourself please.

Trouble Shooting:

Gee, it looks like you are going to need to go that extra mile, and I am s o rry that your unit is not up and running perfectly at this point. Don’t despair because all of TPC is behind you, and we will get you going with the minimum amount of grief. Please do a recheck of the list above found in “Final Check and A d j u s t m e n t : ” . If you are technically inclined, you may refer to the schematic drawing on pages 14-15, where you will find a ‘DC TEST VOLTAGE’ chart . C o m p a re these voltages with the readings that you obtain in your a m p l i f i e r. The PCB has all of the Test points clearly marked for your convenience. Record these readings and if you are having diff i c u l t i e s solving the problems with your amp, we are here to take you step by step through the unit to get it working. Give us a call or write us via fax or email detailing your contact information and amp symptoms including the voltages at all the test points. B a rring that, simply arrange to re t u rn it to us and we will get it going for you. May I wish you then a belated Happy Listening!

q Tu rn the amplifier ON and watch for smoke signals, and if all goes

well, after 3 minutes shut it OFF again.

q Unplug the power cord. Wait 5 minutes before touching anything

inside of the chassis.

q The trimmer pot will not likely need to be adjusted. It is there to

balance the AC ripple from the power supply across the 300B. This will minimize the amount of hum that you may hear on your speakers. If you want to try adjusting it, you could look at the amplifier O/P with a scope or listen closely to your speakers to null the hum out. CUE: Another method you may try to reduce the low-level hum is to re v e r s e the two red wires of the high voltage windings. Need I say that you must unplug the power cord before changing these wire s ?

Last Step:

q This is the last step, install the bottom cover with the twelve black

6-32 1/4” Philips screws. The vents are positioned towards the front of the chassis.

q At this time it appears that you are ready to introduce your new

S E T-300B into its new home. I trust that you will not need more i n s t ructions on how to install the unit in your system.

In Closing:

It has been a pleasure working with you during the construction of this p roject. Likewise, I hope that the experience has been a pleasant one for you as well. TPC and I believe that you will enjoy your new Assemblage SET-300B Amplifier for many years to come. Please feel f ree to call or write us to let us know any of your comments on this p roject, good or bad. Your input is valuable to us to continue to supply you, the D.I.Y. e r, with the best possible kits available on the market today and tomorro w. Take care and Happy Listening.

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Technical Specifications

Note: Specification ratings based on the nominal power line input for the country in which it is used

Power Output:

Stereo 8 watts per channel continuous both channels driven,

into 4, 8 or 16 Ohms (user selectable),

Mono 16 watts continuous into 8 or 16 Ohms (user selectable)

Frequency Response (8 watt, 4 ohm): 20Hz - 0.7dB, 20kHz - 0.9dB

THD+N: ≤ 3% at rated power, 20Hz to 20kHz both channels driven.

Typically 0.9% 1 kHz at 1 watt level

Input Sensitivity: .55V for Rated Power

Input Impedance: 100 Kohm

Hum and Noise: -89 dB below rated power IHF-A weighted

Gain: 23 dB

Power Requirements: 100-120VAC 50/60Hz

(Export 220-240VAC 50/60Hz) 200 VA maximum

Tube Complement: 2-6BX7GT, 1-6SN7GT, 2-GZ37 (2-300B - customer option)

Dimensions: 17" (40.8 cm) W x 8.5" (20.4 cm) H x 13.5” (32.4 cm) D

Weight: 50 Ibs. (23 kg) Net (unpacked)

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Assemblage SET-300B Signature Upgrade Kit Preview:

At this time I would like to re f resh your memory to the fact that as with all of our other Assemblage kits, this SET-300B amplifier also has an additional special selection of upgrade parts available.

A quick run down of the Signature Upgrade parts include Multi-Cap RTX polystyrene capacitors, additional Multi-Cap and Wi m a bypass caps, more replacements such as Black Gates, Vishay and Caddock resistors, Kimber Kable Ultraplated RCA jacks, Kimber Kable AGSS silver wire, D.H. Labs Silver Sonic input wiring for each channels, Cardas silver/rodium/gold plated dual binding posts, and E.A.R. isolation feet. The complete step by step instructions for the change over is also included, plus WBT 4% silver solder.

You will also notice the rear panel chassis knock out, and that it must be for something. That something is an attenuator so that you may use the amplifier directly connected to your favorite source equipment. This is cool, but not all that exciting yet? Well OK, we have made provisions to install a pair of large chassis mount Black Gate electrolytics in the power supply for each channel! ...So bite on that and chew it for awhile.

You may get these parts as a kit to install yourself, or we will also install it for you into your Assemblage SET-300B Amplifier.

As you would expect the Signature Upgrade Kit will improve the overall tonal balance and realism, expand the soundstage and allow you to get more intimate the very inviting harmonics of the sweet 300B sounds.

As I am finishing off this manual, I am thinking that this SET-300B amplifier has a theme that is a little unique from our other kits, and that is user flexibility. For example, we have provisions made to accommodate many choices of output coupling caps, like Exotia TFT, Seti InfiniCap, Jensen Copper Paper in Oil and many of these in .22uF to .47uF in sizes. In the Left and Right Filter Banks we have a special position designed to hold a pair of 100uF Black Gate chassis mount caps. You have the simple option to run this chassis as a Mono Block amp to double the power. For the minimalists why not install one of our many attenuators that will fit into the chassis and s t reamline the signal path? We must not forget that you have the ultimate say in which O/P 300B tube you would prefer in this fine kit! TPC stocks a big high five of some of the best 300B tubes available on the market today. So let us know what your big heart desire s .

Guarantees and Warranty

Satisfaction Guarantee - If you are not satisfied with the sonic perf o rmance and build quality of the Assemblage SET-300B, you may re t u rn it, prepaid, within 30 days of date of purchase for a full refund of the original purchase price. Please call The Part s Connection for an RMA (Return Materials Authorization) Number and shipping instru c t i o n s .

Assembly Guarantee - We guarantee that if you can’t get the Assemblage SET-300B running, The Parts Connection will!

Tw o - Year Limited Wa rranty - The Parts Connection warrants to the purchaser that each Assemblage SET-300B Amplifier is fre e

of manufacturing defects for a period of two (2) years from date of purchase, excepting tubes, which are warrantied for 90 days f rom date of purchase. To receive this warr a n t y, the original purchaser must complete and mail the enclosed Wa rranty Registration to The Parts Connection within thirty (30) days from date of purchase. During this two (2) year period, The Parts Connection will re p a i r or replace any defective components free of charge. Please call The Parts Connection for an RMA (Return Materials Authorization) Number and shipping instructions. This Wa rranty is subject to the following conditions:

1. Wa rranty applies only to the original purc h a s e r.

2. The warranty is void if the product has been handled other than in accordance with the instructions in this Constru c t i o n and Operation Manual, abused or misused, damaged by accident or neglect or in being transported, or has been t a m p e red with or modified.

3. Wa rranty does not cover normal maintenance.

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Toll Free Help Line

If you have any questions regarding the assembly or installation of the Assemblage SET-300B kit, please give us a call at The Parts Connection at:

Toll Free: 1-800-769-0747 (U.S.and Canada) Telephone: (905) 829-5858 Facsimile: (905) 829-5388

2790 Brighton Road, Oakville, Ontario, Canada L6H 5T4

We will also be glad to help you with any of your parts needs, that you may find in our parts catalog. Keep an eye out for more kit products from Assemblage, too!

Rev. 4