Manley Labs NEO-CLASSIC 300B User Manual

MANLEY

LABORATORIES, INC.

OWNER'S MANUAL

MANLEY NEO-CLASSIC SE / PP

300B AMPLIFIER

MANLEY LABORATORIES, INC.

13880 MAGNOLIA AVE.

CHINO, CA. 91710
TEL: [phone]
FAX: [phone]

CONTENTS

SECTION PAGE

INTRODUCTION 3

MAINS CONNECTIONS 4

CONNECTING YOUR AMPLIFIER 5

DIAGRAM 2 TOP PANEL 6

BIAS PROCEDURES 7

OPERATIONAL NOTES 8

SPECIFICATIONS 9

WARRANTY 10

WARRANTY REGISTRATION 11

INTRODUCTION

THANK YOU!...

for choosing the Manley Neo-Classic SE / PP 300B Monoblock Amplifiers. The Manley Neo-Classic SE / PP
300B Amplifiers use only the best available components, with the shortest and cleanest signal path possible.
These amps have the unique ability to switch from Single ended to Push-Pull topologies and the ability to adjust
the amount of negative feedback in 1 dB steps. This amp is designed to provide our customers with a versatile
little amplifier that can do it all.

Let us start out by stating our opinions about amplifier topologies. Historically, we have been manufacturing very
highly regarded tube amplifiers since before tubes were considered the best option for hi-fi music lovers. We have
manufactured a very wide range of amplifiers with power ranging from 15 watts to 800 watts and with a
corresponding variety of tubes. This is not our first amp to feature 300Bs nor our first single ended triode amp.
We build a $15,000 70+ watt single ended amp on a custom basis. In our experience, the more power an amplifier
is capable of - the better it will be at providing acceptable low frequency quality. It is not easy to produce a very
powerful amp with highs of the same quality as the lows. To do that we had to start manufacturing our own
transformers. This is the major development that allowed us to produce an amplifier that could switch from
single-ended to push-pull. We had to design and build a very unusual transformer first.

When several other manufacturers started selling single-ended amps with 5 to 9 watts of power, we understood
subjectively and objectively the good part of the story - the superb mid range - the delicate transient detail - the
inherent simplicity. The bad news was that there were almost no speakers efficient enough to be a dynamic viable
system. The worse news was that either these single-ended amps cost more than the condo or they had specs that
could only be a joke. As the triode fans increased, more efficient speakers became available and several fanatics
began to dismiss push-pull as a bad thing to be avoided at all costs. We objected to such blanket generalities and
stressed that the push-pull done right with truly balanced transformers, quality parts throughout and a well
designed circuit has proven to be a superb technique. We also like single ended amps, but few and far between,
mostly because we prefer a flat frequency response and low distortion. We knew could do it better.

We set out to design an amplifier that would appeal to us and to you and to the critics. It would be single-ended
with more power than most for fans of that topology. It would be switchable to push-pull for fans of that school
and for those who want it both ways - to compare for themselves, and to use each mode depending on the music.
We decided to further extend our own feature of variable negative feedback to a greater range - from none to 10
dB. Some prefer zero negative feedback and some prefer more. The advantage of a little negative feedback is
better specifications in general. Williamson, in 1947, not only described the advantages but described the loss of
some transient information with greater than 20 dBof feedback. We typically use 3 to 6 dB in other amps. Even
with zero negative feedback, this amp is cleaner and flatter than any single-ended amp we know of. One
interesting aspect of negative feedback is it gives a higher damping factor. Conventional wisdom would have us
think that the higher the damping factor - the better. Our experience is that the optimum damping factor is not
infinity and that it depends on the speaker, the room, and the taste of the listener. In other words, the optimum is
variability, and this we provide. This amp satisfies us as long time amplifier builders, amazes the critics in several
well known magazines and is bound to satisfy the you with the ability to fit into your system and your
expectations.

READ THIS PAGE BEFORE YOU SET UP THE AMPS, PLEASEREAD THIS PAGE BEFORE YOU SET UP THE AMPS, PLEASE

READ THIS PAGE BEFORE YOU SET UP THE AMPS, PLEASE

READ THIS PAGE BEFORE YOU SET UP THE AMPS, PLEASEREAD THIS PAGE BEFORE YOU SET UP THE AMPS, PLEASE

IMPORTANT Never operate this amp without a speaker or load connected. Never drive this amp into a short

circuit. Most solid state amps can be operated without a load or speaker and some can drive a short circuit because of
protection circuitry. These are different - Like most tube amps the output power is less affected by changing the load
impedance within the range of 4 to 16 ohms, however extremes like a short or open circuit are to be avoided. The result
could be damage to transformers or tubes. The warranty does not cover this damage if it occurs.

INSERTING TUBES

We ship these amplifiers with the 300B tubes boxed separately because they are fragile and expensive. You will have to
insert these before turning the amplifier on. Carefully upack the 300B tubes from their box and ensure they have not
been physically damaged. We have labelled each tube and its corresponding socket. Notice that there are two thick pins
and two thinner pins on the base of the 300B. The two thick pins MUST be alligned and oriented to go into the two
larger holes in the socket. It is possible to plug this tube in the wrong way - so pay careful attention to the pin alignment
on these tubes. Now plug the right tube into the right socket the right way. This is easy but important.

Pay special attention to pinPay special attention to pin

Pay special attention to pin

Pay special attention to pinPay special attention to pin
alignment ! The 2 small pins mustalignment ! The 2 small pins must

alignment ! The 2 small pins must

alignment ! The 2 small pins mustalignment ! The 2 small pins must
go into the 2 small socket holes.go into the 2 small socket holes.

go into the 2 small socket holes.

go into the 2 small socket holes.go into the 2 small socket holes.

The tubes must be insertedThe tubes must be inserted

The tubes must be inserted

The tubes must be insertedThe tubes must be inserted
carefully and speakers carefully and speakers

carefully and speakers

carefully and speakers carefully and speakers
connected before turning connected before turning

connected before turning

connected before turning connected before turning

GENERAL NOTES

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LOCATION & VENTILATION

The Manley SE/PP 300B Monoblock Amplifiers must be installed in a stable location with ample ventilation. Allow a
minimum of 2 inches of clearance on the top and sides of the amplifiers, such that a constant flow of air can flow. Do
not place amplifiers directly on high pile carpet or any other surface that will block the ventilation vents underneath the
amplifiers. If you have small children or pets, you should consider placing the amplifiers out of reach to prevent damage
to the amplifier or damage to your small children or pets by the amplifier as the tubes do run with high envelope
temperatures.

WATER & MOISTURE

As with any electrical equipment, these amplifiers should not be used near water or moisture. If liquid enters the
amplifier, it must be immediately returned to your dealer for servicing.

SERVICING

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

SPECIAL NOTES

Before turning the amps on - Connect your preamp to the amp inputs then turn the preamp on. Tubes may become loose
during transit. Straighten and press down each tube before plugging the amplifier into the mains socket. Furthermore,
do not touch the tubes after the amplifier has been switched on, as the tubes become very hot during operation and

should only be handled after the power has been turned off and the tubes have cooled.

HUM

As with most monoblock amps with the 3 pin IEC power connectors, you may need one or two "3 pin to 2 pin" power
adapters or "cheaters". This will stop ground loop related hum. Usually only one amp will need this.

WARNING!

TO PREVENT THE RISK OF ELECTRIC SHOCK DO NOT OPEN THE CABINET.
REFER SERVICING TO QUALIFIED PERSONEL.