Manley 300B User Manual

MANLEY

LABORATORIES, INC.

THE NEO-CLASSICTHE NEO-CLASSIC

THE NEO-CLASSIC

THE NEO-CLASSICTHE NEO-CLASSIC

300B PREAMPLIFIER300B PREAMPLIFIER

300B PREAMPLIFIER

300B PREAMPLIFIER300B PREAMPLIFIER

OWNER'S MANUALOWNER'S MANUAL

OWNER'S MANUAL

OWNER'S MANUALOWNER'S MANUAL

TUBESTUBES

TUBES

TUBESTUBES

brought to you by the clever folks at:

MANLEY LABORATORIES, INC.

13880 MAGNOLIA AVE.

CHINO, CA. 91710 USA

TEL: [phone]
FAX: [phone]

www.manleylabs.com

RULERULE

RULE

RULERULE

Rev. 10/08

CONTENTS

SECTION PAGE

INTRODUCTION & GENERAL NOTES 3

MAINS CONNECTIONS 4

CONNECTING YOUR PREAMPLIFIER 5

FIGURE 1 FRONT PANEL 6

FIGURE 2 TOP VIEW 7

FIGURE 3 BACK PANEL 8

OPERATIONAL NOTES 9

SPECIFICATIONS 10

WARRANTY 11

WARRANTY REGISTRATION 12

2

INTRODUCTION

THANK YOU!...

for choosing the Manley Laboratories "The 300B Preamplifier". Handcrafted in Chino, CA, the Neo-Classic 300B
Preamplifier uses beautiful sounding parts in a clever and clean signal path. This Preamp features the 300B direct
heated triode as the line and headphone driver. The 300B is typically used in low power amplifiers as a power tube.
These 300B-based amps generally deliver 5 to 9 watts single-ended and cost from $3,000 to over $100,000! Some of
these amps sound very nice coupled with efficient speakers. Our Neo-Classic 300B SE/PP Power Amplifier uses a
pair of 300B’s that can be operated single-ended or push-pull, and delivers up to 22 watts. We consider the 300B to
be an extremely luscious tube for low-power purposes. Driving headphones and cables is a natural application for
these tubes. This is where the impedances are not too low and the power requirements are not too high but where
smaller triodes tubes might run out of steam. In our Neo-Classic 300B Preamplifier, we combine the classic 300B
with another classic - the octal-based 6SL7GT dual triode to perform the amplification duties. To complement this
tube choice we also employ tube-based rectification and regulation as well as our usual extreme filtering with gobs of
large filter caps.
To complement our best sounding line driver to date, we surround it with proven passive compnoents such as gold
plated connectors, high purity copper wire, Mil-spec printed circuit boards with extra thick copper and plating,
ceramic sockets, and custom-designed transformers. All the audiophile goodies are in here and together the sum total
is a beautiful sounding preamplifier which we know will provide years of faithful service.

LOCATION & VENTILATION

The Neo-Classic 300B Preamplifier must be installed in a stable location with ample ventilation. It is recommended,
if this unit is rack mounted, that you allow enough clearance on the bottom of the preamp such that a constant flow of
air can flow through the ventilation slots. The top should be given enough clearence to allow sufficient ventilation
above the tubes. We also recommend that the preamplifier be placed at least 10 inches away from its amplifier.

WATER & MOISTURE

As with all electronic equipment, this unit should be kept away from moisture of any kind. You’re allowed to weep
with joy at the sounds it makes, but keep those salty tears away from the power supply!

SERVICING

The user should not attempt to service the preamplifier beyond that described in the owner’s manual. Refer all
servicing other than tube replacement to Manley Laboratories.

SPECIAL NOTES

The 300B’s are packaged separately to prevent damage. You will need to carefully plug them in before powering-up
the preamp. Pay attention to the size of the pins to properly align the tubes before inserting. The large pins go into the
large sockets. It is difficult but possible to insert the 300B’s wrong and damage the preamp. Tubes may become loose
during transit. Straighten and press down each tube before plugging the preamplifier into the mains socket.
Furthermore, do not touch the tubes while the preamplifier is switched on, as the tubes do become very hot during
operation and should only be handled after the power has been turned off and the tubes have cooled.

Please read over this entertaining and enjoyable owner s manual carefully as it contains information essential
to the proper operation and maximum enjoyment of this instrument.

Thank you again, and please enjoy your new Neo-Classic 300B Preamplifier! (and the clever Owner s Manual.)
UNPACKING: Unpack the preamplifier carefully and make sure that all supplied accessories are present. Carefully
examine all items for any possibility of shipping damage. All the tubes should show no signs of distress such as
chipped glass, loose internal components or obvious breakage.
If the preamplifier is damaged or fails to operate, notify the shipper or your dealer or us or your local authorities
immediately. Or if you suspect The Shipping People threw it off the airplane and onto your front porch whilst flying
overhead at 30,000 feet, notify the shipping company without delay and complain to them as we only guarantee this
unit to be able to survive a drop of 23,487 feet or less.
Your Neo-Classic 300B Preamplifier was packed with extreme love and includes the following components and
accessories:
a) 1 each, 6 foot IEC 3-conductor power cable (that you will probably replace with an expensive audiophile cord
anyway.)
b) 1 each, Owner s Manual (that we hope you will keep reading.)
c) The tubes: 2 x 300B, 2 x 6SL7GT, 2 x OD3, and 2 x 5U4 vacuum tubes

It is prudent to retain the shipping materials for future use, as they are custom-formed for the preamp and
will greatly minimize the chance of shipping-related damage should you ever need to put your precious
Neo-Classic 300B Preamplifier in the careless hands of The Shipping People again.

3

MAINS CONNECTIONS

Your Manley Neo-Classic 300B Preamplifier has been factory set to the correct mains voltage for your country.
(Well, that is what we intended to do when we knew where it would be initially shipped.) The mains voltage
that we built this Manley Neo-Classic 300B Preamplifier to operate with is marked on the serial badge, located
on the rear panel. Check that this complies with what comes out of your wall.
There is no voltage changeover switch! There are jumpers on the power transformer PCB that are soldered to
put the transformer primaries in parallel for 117v operation or into series for 230/240v countries so be sure to
check the sticker and the serial number voltage indication for proper mains voltage. Failure to properly comply
with mains voltage requirements can cause extensive damage to the system, which of course would not be
covered by the warranty. If you relocate from, say, a 120v country to a 240v country, you will need to change
power transformer jumpers or use a step-up outboard converting transformer.

The mains fuse may be checked by first disconnecting the IEC mains cord from the power supply’s power inlet
plug. Then gently push and rotate counterclockwise the fuseholder retainer cap. The fuse and cap should spring
outward toward your fingers. Inspect the fuse for the proper rating; change if necessary. Refer to the fuse rating
chart in the specifications section of this manual. If you do not know what a blown fuse looks like, you may
measure for continuity across the fuse ends. If your meter reads “OL” when you measure across the fuse, that
means “Open Leads” and that would mean the fuse is blown. A blown fuse usually indicates A Very Bad Thing
occurred. If this has happened to you, try to figure out why it may have happened. (Using a Fast Blow fuse
when
we have specified a SLO-BLO fuse is one reason...) If you have no idea why a fuse might have just blown on its
own, you might want to consult with Manley Labs or your dealer for further advice as something Very Bad
might
have occured, like the power transformer might have decided to retire early.

One way this could happen is by running the wrong mains voltage into the unit. Be sure not to do that.

If you live in a strange place...

Export units for certain markets have a moulded mains plug fitted to comply with local requirements. If your
unit
does not have a plug fitted the coloured wires should be connected to the appropriate plug terminals in
accordance
with the following code.
GREEN/YELLOW EARTH terminal
BLUE NEUTRAL terminal
BROWN LIVE terminal
As the colours of the wires in the mains lead may not correspond with the coloured marking identifying the
terminals in your plug proceed as follows;
The wire which is coloured GREEN/YELLOW must be connected to the terminal in the plug which is marked
by
the letter E or by the safety earth symbol or coloured GREEN or GREEN and YELLOW.
The wire which is coloured BLUE must be connected to the terminal in the plug which is marked by the letter N
or
coloured BLACK.
The wire which is coloured BROWN must be connected to the terminal in the plug which is marked by the
letter L
or coloured RED.

DO NOT CONNECT OR SWITCH ON THE MAINS SUPPLY UNTIL ALL OTHER
CONNECTIONS HAVE BEEN MADE. (...or else...)

4