Audio Note DAC Kit 3.1, DAC Kit 4.1, DAC3.1 Signature Kit Instruction Manual

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Manual Version 2.2 – March 2011

Build instructions for DAC3.1, DAC3.1 Signature, DAC4.1 Limited Edition

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Table of Contents

Section1: Introduction ............................................................................................................................................................ 4

Overview ............................................................................................................................................................................ 5

Component Placement Breakdown .................................................................................................................................... 6

Electrical Safety Warning ................................................................................................................................................... 8

Section 2: Mechanical Assembly ........................................................................................................................................... 9

Installing the feet ................................................................................................................................................................ 9

Mains Transformer, Choke, and Mains Installation ............................................................................................................ 9

Configuring the Primary Winding for your World Region .............................................................................................. 11

Installing the IEC Socket (AC Socket) and Rocker Switch ........................................................................................... 14

Installing the Choke ...................................................................................................................................................... 15

Installing the Mains Transformer .................................................................................................................................. 15

Wiring up the Mains ................................................................................................................................ ...................... 16

Shield Positioning ......................................................................................................................................................... 17

Section 3: M2 Power Supply ................................................................................................................................................ 19

M2 Power Supply Board Parts List .................................................................................................................................. 20

M2 Power Supply Board Construction Steps ................................................................................................................... 21

Installing the Valve Bases ............................................................................................................................................ 21

Installing the Resistors ................................................................................................................................................. 23

Installing resistors in the HT ADJUST position ............................................................................................................. 25

Zener Diode Installation ................................................................................................................................................ 26

Electrolytic Capacitor Installation .................................................................................................................................. 27

Installing the Bridge Rectifier ........................................................................................................................................ 29

Installing the Non-Polarized Capacitors........................................................................................................................ 29

Wiring the M2 Power Supply Board .............................................................................................................................. 30

Filament Component Section of the M2 Power Supply Board ...................................................................................... 33

Regulator Installation .................................................................................................................................................... 34

Installing the LED Harness ........................................................................................................................................... 35

Remaining Wire Connections ....................................................................................................................................... 35

Installing the Heatsink .................................................................................................................................................. 36

Installing the Choke Wire .............................................................................................................................................. 37

Inter-wiring to the Mains Transformer ........................................................................................................................... 38

Securing the Regulators to the Heatsink ...................................................................................................................... 41

Section 4: M2 Power Supply Testing ................................................................................................................................... 43

Preparations ..................................................................................................................................................................... 43

Fitting the Mains Fuse .................................................................................................................................................. 43

Installing the LED Indicator ........................................................................................................................................... 44

Installing the tubes ................................................................ ................................ ........................................................ 44

Tidying Up .................................................................................................................................................................... 44

Ohm Check ...................................................................................................................................................................... 45

Electrical Testing .............................................................................................................................................................. 45

Voltage Check Summary ................................................................................................................................................. 47

DC Voltage Checks ...................................................................................................................................................... 47

AC Voltage Checks ...................................................................................................................................................... 47

Section 5: Digital Power Supply PCB .................................................................................................................................. 48

Parts List .......................................................................................................................................................................... 48

Construction ..................................................................................................................................................................... 48

Installing the LED‟s ....................................................................................................................................................... 49

Installing the Capacitors ............................................................................................................................................... 49

Installing the Diodes ..................................................................................................................................................... 50

Installing the Resistors ................................................................................................................................................. 51

Board Installation and Wiring ........................................................................................................................................... 52

Section 6: Install the Screen ................................................................................................................................................ 54

Section 7: Installing the Digital PCB .................................................................................................................................... 55

Digital Board Overview ..................................................................................................................................................... 55

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Digital Board Installation .................................................................................................................................................. 56

Section 8: Digital Board Power Supply Connections ........................................................................................................... 57

Section 9: Line Board Construction ..................................................................................................................................... 58

Installing the Valve Bases ................................................................................................................................................ 58

Parts List .......................................................................................................................................................................... 58

Installing the Resistors ..................................................................................................................................................... 59

Installing the Electrolytic Capacitors................................................................................................................................. 61

Installing the Film (non-polarized) Capacitors .................................................................................................................. 61

Board Orientation ............................................................................................................................................................. 62

5687 Filament Wiring ....................................................................................................................................................... 62

Section 10: Installing I/V transformers ................................................................................................................................ . 63

Wiring the I/V Transformers ............................................................................................................................................. 64

Section 11: Connecting the 5687 Output ............................................................................................................................. 65

Connecting the 5687 HT to the power supply .................................................................................................................. 65

Connecting the Output Transformers ............................................................................................................................... 65

Output Transformer Type 1 (Single-ended Only) ......................................................................................................... 66

Output Transformer Type 2 (Single-ended or Balanced) .............................................................................................. 67

Section 12: Source Selection and Switching ....................................................................................................................... 68

Installing the Input Selector Switch .................................................................................................................................. 68

Input Connections ............................................................................................................................................................ 69

Connecting the RCA Input ............................................................................................................................................ 70

Connecting the USB Input ............................................................................................................................................ 72

Connecting the XLR Input ............................................................................................................................................ 73

Section 13: Turn-on Procedure ............................................................................................................................................ 74

Final Thoughts ..................................................................................................................................................................... 75

Appendix .............................................................................................................................................................................. 76

Resistor Color Code Reference ....................................................................................................................................... 77

Analog Board Schematic .................................................................................................................................................. 78

M2 Power Supply Board Schematic ................................................................................................................................. 79

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Section1: Introduction

NOTE: This manual is for the DAC3.1, DAC3.1 Signature, and DAC4.1 kits - The kits are all the same except that the component level is increased with each kit the - The DAC3.1 can come as RCA or RCA/Balanced while the DAC4.1 using the C-core output transformers comes in RCA/Balanced.

Thanks for purchasing the AudioNote DAC Kit 3.1 or 4.1. Our goal is to provide you with the highest quality Kit that you will build from scratch with these instructions. If you have any questions or comments during the build feel free to contact us and we would be happy to help out.

You will need a soldering iron or soldering station with a sponge along with wire strippers and a Phillips screwdriver. A nut driver or a pair of pliers would be useful as well. We have divided the manual up into a series of step-by-step instructions for the successful build and debug of the kit. There are several places during the build that you will perform tests and/or checks to make sure that you are on track. This way when you complete the kit you will know that all the major sections are working.

You will find a number of component bags supplied with your kit. These bags will be referred to throughout this manual. Here are some tips from working with many kit builders over the last few years:

 Perform your work in small manageable chunks. Do not be in a hurry to listen to your finished kit.  Savor the build experience. Here‟s a chance to really get to know your audio kit that will give you many hours of

enjoyment.

 Better to work on a section and then spend the time to check over the section rather than just carrying on.  The kit building experience should be a pleasant one so find a place that you can build the kit with relative peace

so you can concentrate on the instructions.

 If you plan for a long build stretch on a Saturday afternoon for example then take plenty of breaks with constant

re-checks of your work.

Whilst working through this manual, please feel free to give us your feedback and any other information that may allow us to improve the build experience.

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Overview

Here is a rough guide to the steps you will be following. You may want to use this page as a general checklist, crossing out each item as it is done.

1. Install Feet on Chassis

2. Install M2 Mains Transformer and Choke into chassis

3. Connect up IEC section (IEC/rocker, Mains transformer)

4. Build M2 Power Supply Board

5. Wire up Mains transformer to M2 power supply

6. Build DAC PS PCB

7. Wire up Mains transformer to DAC PS board

8. Build 5687 analog Board

9. Wire up Filaments and HT from M2 Power supply Board

10. Install Digital Board in chassis

11. Connect Digital Power Supply leads to Digital Board

12. Connect Digital Board to 5687 Board (via IV transformers)

13. Connect 5687 analog board to output transformers

14. Connect output transformers to audio outputs

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Component Placement Breakdown

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The graphic below shows the block diagram overview of how the DAC works:

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Electrical Safety Warning

There are sufficient voltages in this kit to give you a very nasty and harmful shock so be careful when powering on, debugging, and probing around.

Please be aware of proper electrical safety. Please contact AudioNote kits via phone or email to discuss any precautions necessary when building the kit if

you feel unsure about what you are doing at any stage of the build.

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Section 2: Mechanical Assembly

In this beginning section we will start by installing the 4 feet from the Fittings Bag then we will install the Mains transformer and Choke as shown in the pictures below.

Installing the feet

Insert 4 feet in the bottom of the chassis. Fix them each in place using an M4 nut and washer.

Mains Transformer, Choke, and Mains Installation

Above you can see the Mains transformer that is used with the M2 Power Supply. The first step is to take the supplied M4 GND lug from the Hardware Bag and solder it to the end of the green wire.

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Trim the wire to about __ inches.

Strip about ¼” of insulation off the end of the green wire.

Tin the bare wire by adding solder to the end.

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Add solder to secure the GND Lug to the end of the wire.

Configuring the Primary Winding for your World Region

Next step is to decide what world voltage you require – for example we have some of the most popular regions listed below:

United States

120v

Canada

120v

230v or 240v

Europe

230v / 240v

Hong Kong

220v

In order to wire up the for 120V operation we will need to connect the primaries as shown below:

The graphic shows above the correct wiring for of the Primaries for 120V operation where the 0 of one winding connects to the 0 of the second winding & the 120 of one winding connects to the 120 of the second primary winding. Check the chart on the next page for the correct PRIMARY winding for the world Voltage you live in.

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Now we must configure our Mains transformer for the World Voltage that we reside in. For this example we will show 120V Operation.

Start by cutting two short pieces of wire approx 2” in length each, stripping the insulation off the ends and tinning the wire.

Then we will inter-wire the Mains transformer primaries.

Remember, we are wiring here for 120v - if your region is different then you will need to consult the wiring chart on the previous page to determine how you inter-wire for your region.

From the IEC bag we want to take the brown and blue wires with the crimps on one end.

Trim the wires to about _____ inches in length and then solder on to the correct Mains transformer primary tags for your region.

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Here, the wires are soldered onto the top-most 0v and the bottom-most 120v for North American/Canadian 120v.

Remember, we are wiring here for 120v - if your region is different then you will need to consult the regional wiring chart to determine how you inter-wire for your region.

Installing the IEC Socket (AC Socket) and Rocker Switch

The rocker switch simply snaps into pace in the chassis slot.

Use the CSK M3 10mm screw and M3 nut to secure the IEC socket into position.

Here you can see the correct installation of the IEC socket and rocker switch from inside the chassis.

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Installing the Choke

Since the Choke fits into a tight location we suggest you put the screws and washers into position through the holes in the choke covers – then lower the choke into position making sure that you align with the non painted hole - see opposite.

Note the wires at the back of the choke.

The left-most picture shows the final position of the choke from inside the chassis.

The central picture shows its position under the chassis where you will now secure the 4 holes of the choke with serrated M4 washers and M4 nuts.

Installing the Mains Transformer

The picture opposite shows the correct orientation for the Mains Transformer.

The following instructions will show how this is achieved.

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When installing the Mains transformer be sure to line it up with the unpainted hole in order to ensure a ground connection.

Secure the transformer at all four corners.

Wiring up the Mains

Once the transformer is installed you can connect up the Blue and Brown Crimped wires from the Mains transformer directly to the Rocker Switch.

Also connect the green earth wire from the mains transformer to the GND lug as shown opposite.

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Add the twisted wire (Cable #3) and the ground wire (Cable #4) as shown in the graphic opposite.

Let‟s add one final GROUND wire connection from the M4

screw in the chassis. Take a piece of bare wire and solder it between the V300

and 0 terminals as shown opposite. Next, take a terminated ground wire and strip the un-terminated end and solder it to the short that you have just made. The other, terminated, end connects to the chassis ground post.

Shield Positioning

I would like to explain where the shield fits at this stage – you won’t actually be installing this until the end of the build but by then there will be a number of things inside the chassis.

Take a look at the shield provided and locate the hole underneath that has no paint on it – this will match up with a hole on the chassis that is also unpainted in order to ensure a good grounding of the SHIELD when in stalled in the chassis.

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Here you can see the correct installation of the shield – You will need to remove it later on when we wire up to the Mains transformer but for now you can leave it in and show off your wonderful work to your wife!

This concludes the IEC Wiring section for the Mains Transformer. You may want to double-check your work at this point. Also, make sure that the crimped end on the Rocker switch are not

coming into contact with each other - make sure there is plenty of clearance. If you want to add some solder to hold them into place that is fine but I would wait a little bit. Also remember that you can use the rubber hoods that are supplied to cover up the rocker and IEC plug and it is a matter of threading the crimped end through the rubber hood.

With this section completed we are going to move onto the building of the M2 Power Supply Board.

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Section 3: M2 Power Supply

In this section we will be assembling the M2 Power Supply Board PCB.

Here is a view of the parts that you will find in the M2 Power Supply Kit Bag

Most of the parts for this section can be found in the M2 Power Supply bag (although the filament wires may be located elsewhere).

For an experienced builder you can look at the parts list on the next page and get started but I would read through the step by step instructions as we feel that this is the best and most efficient error free method of building the board.

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M2 Power Supply Board Parts List

The Complete Parts list for the M2 board is shown below. For resistor color code chart refer to the APPENDIX. You can also find an 'Interactive Resistor Color Code Calculator' on

our website (available from the Links page).

Category

Quantity

Part

Designator

Capacitors (Electrolytic)

470uf 16V

C2, C4

2200uF 35V

22uF 450V

C6 ,C7

68uF 450V

C3, C5

Capacitors (Non-polarized)

Disc 4700uF 1000v

C10

.22uf 600V

.47uF 600V

Resistors

100R

1K0

R5, R6

2K7

R12

15K

R11

33K

68K

100K

R1, R10

150K

220K

470K

Semiconductor Devices

KBU6J6A

3.5W 150V Zener

Zero Ohm Resistors

D1, D2, D4, D5

1N4007

D3, D6

78S12

U2, U3

Variable Resistor NOTE: This may be replaced with 2x 22K resistors

50K 500mW

VR1

Valve Bases

8 pin valve base

9 pin valve base

Tubes

6X5 Tube

ECL82 / 6BM8 tube

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M2 Power Supply Board Construction Steps

Installing the Valve Bases

Lets start by installing the 8-pin valve base with correct orientation.

The 8-pin (octal) valve base is shown opposite.

It‟s a fairly tight fit into the board so take you will need to

take your time and make sure all the legs are individually positioned over the holes in the board.

Now, let‟s make sure we have the correct orientation - note the Notch on the valve base along with the Notch on the PCB. These need to line up - see next image.

Here you can clearly see the notches lined up – this is a correct orientation of the 8-pin valve base.

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The next job is to solder the valve base into position – Once you have fitted the octal into position I suggest you use a cap or something to support the board so that it is nice and horizontal.

The reason for this is so that the valve base will be soldered into the board nice and level – you may want to solder a pin on one side and then the opposite and then double check that the valve base is nice and level see the following images.

It is only necessary to solder half the valve base whole – feel free to put solder on the entire hole if you feel like you need to do so – I usually pick one side and solder the lead to the board – you may want to pull on the lead to make sure that it is all the way out – sometimes a valve base lead can stick in position.

Next step is to solder in the 9-pin valve base – this one only goes in one way so you can‟t really make a mistake. I would suggest using some tape though to make sure that the valve base is level to the board – then solder a pin on one side and then the other to make sure the valve base is level and that you are on track. See pictures below:

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Installing the Resistors

Resistors

100R

1K0

R5, R6

2K7

R12

15K

R11

33K

68K

100K

R1 ,R10

150K

220K

470K

If you have a voltmeter you can check the value of each resistor prior to soldering in OR you can refer to the color code chart in the above parts list.

Identity the correct resistor and then install in the specified designator (R1 for example).

Resistors have no polarity so it does not matter the orientation but I find that if I stick to one direction from left to right it makes it a lot easier to read the resistors on the board.

RESISTOR NAMING LESSON: When a resistor has a value of lets say 10 ohms we will refer to this as 10R. If the resistor has a value of 10.5 ohms we would say 10R5. When a resistor value is 250 ohms we would say 250R – When it becomes 1000 ohms we say 1K or 1K0 or 1 Kilo ohm. Its common to see 1K5 which would be like 1.5 K ohm or 1500 ohms – Just like when we get to 1 Mega Ohms we would say 1M or 1M0. For 1.2M we would use 1M2 – so this is the standard way of naming resistors – The first resistor we are going to install is the 100R or 100 ohm resistor!

Here we are installing the 100R resistor.

You should locate the reference designator on the board (in this case it is R8) and then do an approx bend on the correct length as we have done opposite.

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Above shows the installation of the 100R resistor into the R8 position – Bend the legs slightly on the underside to keep the resistor in place.

We suggest you install the spacers on the board at this point.

Once you are feeling confident of your resistor installation it is time to solder on the underside of the board.

For first time soldering here are some tips to follow:

1. Clean the tip with a wet sponge after each solder so as not to let resin build up.

2. „Tin‟ the tip (i.e. add a small amount of solder to it) just before soldering.

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Once the joints have been made, give them a quick inspection and touch up any that look suspicious in any way.

Next step is to clip the leads - you want to do this but be careful not to clip off too close to the board where you endanger the pad – see picture opposite for a good example.

Installing resistors in the HT ADJUST position

We used to use a little trim pot in this position – but due to its unavailability we are now using a resistor combination to do this. The diagram below illustrates what we are about to do:

Insert the resistors into position as shown.

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Bend one of the legs over and through the hole in the board as shown - solder into position from the top of the board.

Take the leg of the other resistor and twist it around the leg of the other one as shown opposite.

Here you can see the resistors in position – you will want to solder the two resistors now on the underside of the PCB.

Zener Diode Installation

Semiconductor Devices

3.5W 150V Zener

This is a critical part and therefore warrants its own individual bag.

The Zener diode goes into the D7 Position . You will notice a gray stripe on the zener and you will want

to position this to match the stripe on the stencil on the PCB in D7 position.

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Here you can see the Zener diode installed in the correct orientation.

Electrolytic Capacitor Installation

Capacitors (Electrolytic)

Do not install C2 and C4 at this stage

2200uF 35V

22uF 450V

C6 ,C7

68uF 450V

C3, C5

We are now going to install the Electrolytic Capacitors into the power supply Board. Note that C2 and C4 will be installed at a later stage.

Electrolytic Capacitor Lesson: An electrolytic capacitor is a device that has a positive and a negative side to it. In other words it MUST be installed correctly or it will basically explode. Luckily the modern capacitors have a slow explosion mode that will look like a dragon breathing fire.

Let‟s begin by installing C3. You will notice that the capacitor has some markings on it -

a 68 for 68uF, a 450 for 450Volts, and a large strip down one side which signifies the NEGATIVE side of the capacitor.

You will notice on the stencil on the PCB that there is a + designator on the board and you will need to orient such that the + side is the opposite to the NEGATIVE stripe The electrolytic capacitor also has a longer lead on the POSITIVE side.

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Here we can see both 68uF capacitors (C3 and C5) correctly installed.

Install the remaining electrolytic capacitors that are required at this stage (i.e. C9, C6, and C7).

You can see these installed in the picture opposite.

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Installing the Bridge Rectifier

Semiconductor Devices

KBU6J6A

Install the Bridge Rectifier into position in U1. Note the notch is located facing into the middle of the board

- you will also see a corresponding notch stenciled on the PCB.

Installing the Non-Polarized Capacitors

Capacitors (Non-polarized)

Disc 4700uF 3000v

C10

.22uf 600V

.47uF 600V

Install in C10 the DISC capacitor – this capacitor is not polarized so it does not matter which direction you put it in.

Now the same for C8 which is called a FILM capacitor and also is not polarized so it does not matter the orientation. You will notice on the .22uF capacitor it designates 300 V~. This means that it is rated for 300V AC which is like 600V DC - well within the range of this power supply.

Next step is to install the .47uF AN FILM capacitor into position.

Again this capacitor is not polarized so the orientation does not matter

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Wiring the M2 Power Supply Board

Get your Bag #2 from the Wire Bag as we will be installing the “filament” wires onto the board. We are going to connect

several wires to the M2 power supply board – this is easier to do at this stage.

FILAMENT LESSON: In order for a tube to function it must be supplied with a Filament Voltage – this is basically a DC (or AC) voltage applied to 2 pins on the tube - this is what makes the tube “light up”. We get these filament voltage supplies from the M2 Power supply board - these twisted wires will be supplying the filament voltage to the tubes on the audio board!

Remove the two long twisted wires from the Bag #2 – We will be inserting these into the PCB from the underside of the board.

From the underside of the board you can see how the wires are positioned.

On the topside of the board you can see the wires protruding through in the correct location – the red wire will be the + side and the black wire will be the negative.

You will see the +6V2- Note that we use this board in a number of different configurations for both 12v and 6.3v filaments for different kits – the stencil is always marked 6V2.

Solder the filament wires from the top of the board now and you will then want to clip the tops of the wires - be careful not to let them flick up and hit you in the face!

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Now take the short wire from BAG #2 - we will be using this to hardwire from the 8-pin valve base to the 9-pin valve base.

The graphic to the left shows the connections for the twisted wires.

EXPLANATION: On the M2 Power Supply Board we will have 2 different tubes - a 6X5 and an ECL82. As explained before, in order for tubes to operate they need a filament voltage - we will be supplying 6.3V AC to both of these tubes. The wire we are installing

here is used to “parallel” the 6.3V

AC that will be coming from the secondary of the Mains transformer.

Note in these pictures the twisted wire has been soldered into pins 4 & 5 on the 9-pin valve base.

On the 9-pin valve base note the upper and lower holes through the pins. Connect the current red & black wires to the lower hole on the valve pin.

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Here is the completed connection of the “parallel filament”.

We are now going to install the 6X5 filament wire - this is the THICK black & white twisted wire that is located in Bag #1 of your WIRE BAG.

This is the wire that will connect from the Mains transformer secondary to the 6X5 filament.

Start by stripping about ¼” of insulation off the end of the

wire and then tinning the copper ends – these ends will be inserted into the holes on the 8-pin octal base – the same pins we have already connected to with the Parallel filament wire from the last step.

Use the upper hole on the 8-pin valve base pin to connect these wires.

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Now get out your BAG#3 from the wire bag and we will install the red and black wires that will be used as the B+ (High Voltage) and corresponding Ground wire.

These pictures show the red and black wires installed in the B+ and GND holes on the M2 power supply board. On the right you will solder the red wire on the B+ from the topside of the board - clipping off the remaining lead

- and do the same for the Black GND wire.

Filament Component Section of the M2 Power Supply Board

Semiconductor Devices

Zero Ohm Resistors

D1, D2, D4, D5

1N4007

D3, D6

This section controls the voltages that we will be supplying to the analog output board.

Here we are configuring for 12V filament operation (as used in the L3 Line, L3 Phono, and DAC3.1).

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The 1N4007 Diodes are polarized and therefore need to be installed correctly. In the picture above you will note the D3 & D6 designators which shows a bar – this bar lines up with the gray strip on the zener diode – Note how they are correctly installed.

Go ahead and install the zero ohm components into position and the zener diodes.

Regulator Installation

Two regulators have been provided with the kit – these have been specially made to an exact length by AudioNote Kits. They use a solid core wire so that it is easy to position on the board through the tiny holes – Read this section before doing any soldering!

IMPORTANT: Note the position of the regulators in the pictures below.

Place the regulators into position as shown opposite and below.

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The pictures above and opposite show a successfully configured regulator.

Once these components are in place you can then install the remaining two electrolytic capacitors (C2 and C4).

Installing the LED Harness

Take the LED Harness from your M2 PS bag and you can solder it onto the board as shown opposite. Solder from underside of the board.

Remaining Wire Connections

Take the remaining thick Black & White twisted wire from the BAG#1 and solder it to the 13V6 locations on the PCB.

It does not matter which is red or black as it is an AC voltage signal.

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Then take the twisted thick RED wires and connect these to the 300V 300V on the PCB.

The picture opposite is what your M2 Power supply board should now look like!

Installing the Heatsink

Feel free now to “place” (do not screw in) your newly

assembled board into position in the chassis. Now install the metal heatsink under where the regulators

will sit. This must be firmly attached to the chassis. One more step and then time for a coffee break on a job

well done!

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Installing the Choke Wire

The Black CHOKE that is located at the rear of the chassis and has a red and black wire. you will want to twist these wires by hand and feed them along the shield towards the M2 PCB.

We will now solder these wires directly to the underside of the PCB – You will notice that on the top of the PCB there is marked “CH” in two locations – these are the holes that the CHOKE will be connected to – Flip over the M2 PCB and locate the holes on the under side

You will want to cut the choke wires to the correct length, leaving a nice amount of slack. Trim the insulation from the ends and tin the wires if you see fit. Then insert the wires from the underside of the board - no polarity for red or black so you can follow along with the pictures opposite.

Now that the choke wires have been soldered to the board, you can now place the board back into position.

Well done – we will be soldering connections to the Mains transformer in the next session!

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Inter-wiring to the Mains Transformer

I would suggest at this stage to REMOVE the black shield so that we can work on this side of the chassis.

The following graphic shows the wiring between the M2 PCB and Mains Transformer. Note that the „s econd‟ transformer

is simply another view of the same mains transformer.

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Page 39

We are now going to take the 3 pairs of twisted wires that are already connected to the M2 Power Supply Board and connect these directly to the SECONDARY of the Mains transformer.

Start by taking the RED / RED twisted pair and trim to a

good length and then solder to the „300‟ lugs on the Mains

transformer. I would suggest stripping the insulation off the end of the red wires and tinning. Then place the tinned lead through the lug on the Mains transformer and then apply solder – it is not necessary to twist the lead around the post.

Next step is to take the Red/Black twisted wire that is connected to the 8-pin octal valve base.

For the 6X5 – this is the filament wire which will be supply

6.3V to the 6X5 and ECL82 tubes on the M2 power supply.

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Page 40

The third pair of wires is the Red/Black twisted pair that is connected to the 13V6 on the M2 power supply board.

Note that the 0 tap is not used here. The last wire for hookup in this section will be the long green wire with the GND

lug on one end found in your IEC Kit Bag- Secure the GND lug end on the M4 screw in the chassis and trim and solder from the top of the board the green wire into the GND hole located near the 13V6 pads on the M2 power supply Board.

Now review your connections made in this section using the graphic opposite and wiring table below.

Wire

M2 PCB

Mains Transformer

RED / RED

300v 300v

0(1) V300(2)

RED/BLACK

13V6 13V6

8 8

RED/BLACK

Pin 2 & 7 6X5

0 6.3v

Check that you have made the connection between the chassis GND lug and GND on the M2 PCB.

Check that you have made the connection between the chassis GND lug and 0 on the mains transformer (i.e. the 0 between 300 and 300).

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Page 41

Securing the Regulators to the Heatsink

We are now going to secure the regulators to the Heat Sink that is installed in the chassis.

The picture opposite shows the parts that are necessary to do this.

EXPLANATION: It is ideal to electrically isolate the regulator from the ground on the chassis (i.e. the heatsink) – this way the regulator is floating – we do this with our little insulation kit which consists of a mica layer and a plastic insert. You can get these from the Hardware Bag marked Heat Sink.

Begin by taking one of the mica washers and laying it on the heatsink as shown in the left-most picture.

The plastic insert should be fitted onto the screw as shown in the central picture.

I would suggest that you line up the mica strip with the hole in the heat sink and install the screw and plastic insert into the hole in the regulator.

Then gently screw the regulator into the heat sink- the mica piece may try and move so just gently ease it back into position.

Repeat for the second regulator.

At this point you can secure the M2 power supply board to the chassis with one or more of the M4 screws provided.

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Page 42

That completes our assembly of the M2 Power Supply Board.

Feel free to re install the shield back into position or you can wait until nearer the end of the kit build if you prefer.

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Page 43

Section 4: M2 Power Supply Testing

Preparations

Fitting the Mains Fuse

In this section we are going to electrically test the power supply.

Start by installing a 1A Slo Blo fuse (IEC BAG) into position as shown.

Use a screwdriver or flat edge or your fingers pull the Fuse holder out - you will need to squeeze to completely remove it.

Insert the fuse into the holder as shown opposite.

With the fuse installed into the holder insert back into the IEC plug.

With the Fuse installed we are ready to do some testing!

READ the entire remaining section first before taking any actions!

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Page 44

Installing the LED Indicator

The LED on the M2 Power Supply Board will be the first indicator that we have power – I would suggest just taping the LED – make sure the metal leads of the LED are not touching any other circuitry or chassis – Note the Led has not been pushed in all the way.

Also note that the LED will only work when inserted the correct way around.

Installing the tubes

Let‟s install our tubes into the board – the supplied 6X5 in the 8-pin valve base and the ECL82 (or 6BM8) in the 9-pin base.

Tidying Up

Seeing as we have a number of loose filament and HT wires coming from the PCB, I would suggest taping the ends to make sure that they do not short with one another when we go to test with power!

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Page 45

Ohm Check

EXPLANATION: There are a number of terms that we will be using in this section that we should be familiar with – the HT or High Voltage or B+ is all the same thing – this is the HIGHEST DC voltage in the circuit typically and is the voltage that we will be supplying to the Tubes in our audio signal path.

THE UNIT IS STILL OFF AT THIS POINT If you have a Multimeter set it to OHMS and measure the

resistance from B+ to GND on the M2 Board – you can see from the picture opposite the approx location on the board to find these 2 points. You should see a reading in the 300K ohm range – this is a good sign – if you have a very low ohmage then there could be a problem and you may want to contact us first.

Electrical Testing

Take a power chord and plug in the unit but make sure the amplifier is off.

Before the first power on we suggest the following steps:

1. Make sure that you have a quiet environment when you are turning on for the first time – that way if there is a problem with the circuit you will be able to see & hear a crackle or a vibration or hum etc. if there is any.

2. If you have a Variac then it would be useful to use it so you can power on slowly and check DC voltages – If not we will just turn on.

3. Press the Rocker switch such that the 1 is pushed flat against the chassis.

4. Observe the LED light turning on and also look for glow from the tubes.

5. Get ready to switch off immediately if anything goes wrong.

6. Get your voltmeter ready – you will want to perform a High Voltage check.

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Page 46

First measure from B+ to GND on the M2 PCB (use the ground point closest to the LED section).

You should read approximately 260v DC.

Now measure the filament voltages - these are the connections labeled +6V2- on top of the PCB.

These should be approximately 12v DC.

If there is a problem with any of the above voltages, switch to AC volts and measure the 300 300 points on the M2 PCB – you should get somewhere over 600V AC.

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Page 47

While in AC mode measure the 13V6 pads on the M2 PCB – We have 8 0 8 taps which should give us roughly 16V AC.

Voltage Check Summary

DC Voltage Checks

Location

Approx Reading

B+ to GND

260v DC

+6V2-

12v DC

+6V2-

12v DC

AC Voltage Checks

These are optional if DC voltages are correct.

Location

Approx Reading

300 300

>600v AC

13V6 13V6

16v AC

If you have correct voltage readings on the M2 Power Supply then Congratulations are in order and you have completed the first half of the kit.

Feel free to contact us if you have any problems with your power supply or have any questions up to this point

audionotekits@rogers.com

Also feel free to give us an update that things are going according to plan.

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Page 48

Section 5: Digital Power Supply PCB

In this section we will be building, installing and testing the Digital Power Supply PCB that is used in the DAC2.1 and 3.1 kits.

EXPLANATION: This small board receives an 18V AC signal from the 9-0-9 taps on the Mains transformers and converts it to several DC voltages that are required by the DAC board. The outputs are A+ - AGND - A- , D+ and DGND.

Parts List

Audio Note DAC Kit 3.1, DAC Kit 4.1, DAC3.1 Signature Kit Instruction Manual

Specifications and Main Features

Frequently Asked Questions

User Manual