Price is for a pair!
Be prepared to be seduced like no other 300B power amplifier, The Manley 300B monoblocks will grab hold of the music and then you - and it will not let you go until it is done. These amps will bring you back to your first love - the music itself and not the means of reproducing it.
The wonderfully simple 300B directly heated triode is virtually Lee De
Forest's very first evolutionary 3-element piece, comprising only
filament, input grid and anode output. Brought to reliable perfection by
Western Electric USA and later by Standard Telephones UK as the 4300B,
the 300B was very much intended and widely used for telephony
amplification. But audio enthusiasts of older times knew a good thing
when they saw (heard!) it and the great love affair between the 300B and
music began... and dwindled many years later as the American Western
Electric 300B was taken out of production in the late 1980's making the
genuine ones extremely valuable and, accordingly, very highly prized as
collectors' pieces. With the Asian-driven passion and resultant revival
of SINGLE ENDED topology the call for the 300B to be put back into
production was too overwhelming for the Chinese factories to resist. The
Russian and the re-start of USA manufacture of the genuine Western
Electric original have further expanded the selection. Basic thermionic
simplicity... directly-heated triodes... it is a drug for some, a
religion for others...
With its decidedly (and studiedly) 'retro' physical proportions- very
deep front-to-back dimensions with a narrow side-to-side width, this
layout closely follows concepts of a bygone era, where the
well-conceived intention was to keep the power supply as far as possible
from the hum and noise susceptible octal input tubes. The output tubes
themselves require careful distancing from the mains transformer and, of
course, require pure DC on their filaments. Again, reverence to past
times begs the use of vacuum tube rectification with its very gentle
voltage rise-time. But to bring the performance up to modern demands, we
use two rectifiers to enable the use of very substantial filter /
reservoir capacitors... over 1300 microfarads in the B+ rail- much
improved from the 4 or 8 microfarads utilized in the 1930's.
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 detail, the
inherent simplicity. The bad news was that there were almost no speakers
efficient enough to help form a dynamically viable system. The worst
news was that either these single-ended amps cost more than the condo
and or they had specs that could only be read as 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 phase-balanced transformers, quality
parts throughout and well designed circuitry has proven to be a superb
technique. We also enjoy single-ended topology but only when it is done
right, mostly because we expect flat frequency response and low
distortion out of an amplifier. We knew that we could achieve this in a
properly conceived single-ended design. We chose to rise to the
challenge of designing special circuitry that could be switched "on the
fly" From 12 watts in parallel SINGLE-ENDED to 25 watts in PUSH-PULL
which, we believe is unique in the industry.
The Output transformer (hand-wound in our own factory) is of complex
design employing inordinately high primary inductance to compensate for
the mandatory magnetic "gap" required for the uni-direction current and
voltage flow of the single-ended output stage. Another factor in the
single ended triode saga (currently enjoying a wide spread popularity)
is demand for little (or sometimes zero) negative feedback. We at Manley
Labs believe in the judicious or sensible amount of feedback to refine
and maximize performance. Our Neo-Classic SE/PP300B gives you the choice
in precision switched 1 dB steps to go from ZERO dB's to 10 dB's of
negative feedback. Even with zero negative feedback, this amp is cleaner
and flatter than any single-ended amp we know of. For more information
about variable feedback read Notes on Negative Feedback.
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 you with the ability to fit into your system and your
expectations. BUT REMEMBER PLEASE the overall facts of power ratings
versus loudspeaker sensitivity and room size when electing to venture
into lower power amplifiers (less than 50 watts) and especially when
contemplating single-ended topology. Please read Considerations of Amplifier Power for more info.
As highly regarded as the Retros were by dealers
,audiophiles and reviewers, the
Neos take the design and the sonics to a new level. In 2000, Mitch
Margolis completely overhauled the previous "Retro" model to create the
Neo-Classic Version you see above.. So what's new with this Neo-Classic
version you ask?
Now... onto the techno mumble jumble... here's all the guts improvements we
made in 2001. Mitch spent six months doing all this:
The driver stage was completely re-engineered. Peak output volts of driver increased
by 60V p-p in PP mode. Clever new driver circuit delivers way better drive,
with less punishing plate volts, and less THD. This offers enough drive even for more exotic tubes such as VV30B, etc...
The NEO's have WAY improved power bandwidth. NEO's deliver much more
power at higher and lower freq's than the ol' Retro's did. We did
rescale the B+ and reduced idle plate dissipation on the NEO's 300Bs for
better tube reliability.
New power max ratings are 12 watts in SE mode and 25 watts in PP mode.
BUT because of better bandwidth delivery and better driver "drive" into
300B's these NEO's sound louder and "seem" to be more powerful. They
distort much less early when pushing the power envelope. The power
supply sags-on-demand at a much high point than before for more
headroom. It is all beefier 'n' heftier.
The heater (300B "cathode" which is directly heated triode design) now
40dB less ripple. NEO design has MORE capacity in heater supply and LOTS
of PI filtering! So the result is a quieter amplifier. Big time.
Now in the NEO version, the B+ rectification is all-real-Full Wave
Bridge vacuum tube rectification. Even more better. Especially sonically
for you vacuum tube rectifier fans...
The NEO'S chassis was redesigned to accommodate a much bigger power
tranny. Huger VA. Next frame size up. Cooler running. Much more able to
deliver-on-demand. Less PSU sag. Kick-ass. And now, finally QUIET!
REALLY! There wasn't enough room on the old
Retros for next frame size up to achieve a nice'n'quiet power
transformer design. Now the NEO's chassis is big enough to have a big
enough power transformer that is really silent and running on holiday.
Bias supply is now cleverly cross-coupled so that changing one tube's bias
doesn't whack the other one out. This is very cool.
We even isolated the input B+ for more stable input B+ supply. Again, so
when pushed, the whole amp doesn't drag everybody down with it.
We added a MUTE switch on the front panel. SE-PP switch on the other side of
Power switch at the IEC so all those nasty AC volts don't come up and infect
the input stages.
Discarded the transformer-balanced XLR input. Because WHAT'S THE
At gunpoint, we will make a balanced XLR transformer coupled input
available "upon special request"... but you need to have a bigger gun
than EveAnna does...
Still has those nice sounding MultiCap® coupling caps and even more of 'em....
Now NEO has nice beautiful WBT binding posts that everybody loves. Still has
impedance load switch as before.
Service is now a piece of cake in the NEO design. The main PCB can now be
lifted out for service without a soldering iron... if switches get banged or
broken they can be user replaced with a phillips screwdriver to remove the
bottom stainless-steel (now) cover and then remove faceplate with little
allen key, then unscrew the switch with pliers or (better) correct nut
driver, then unplugged out old switch then new one plugged in with switch
assembly from us. Easy as pie!
But, just in case, we did invent newer stronger foams and packaging so
hopefully no more breakies....
And bottom line, in all our listening tests, this NEO is very much
improved. Now with this six months of re-engineering of the Neo-Classic
SE/PP 300Bs, "THD BE-GONE!!!!"
The Electro-Harmonix Russian 300B tubes are being shipped as standard. That's 300B-EH.
And finally, sorry to say, we had to raise the price to PAY for all this
R&D and nice improvements and so we can start making some money on
this product for a change... (insert trite capitalist expression here).
Sorry folks, that's the way it goes....
So guys, WAIT UNTIL YOU HEAR THEM AND SEE THEM....
then of course, as always, we welcome your comments!
There is reason for our madness....
Cheers, EveAnna Manley
Get the owner's manual for the Manley Neo-Classic 300B Preamplifier RC
Features and Specifications
Manley Neo-Classic SE/PP 300B
- Vacuum Tubes: 2 x 300B (Output), 1 x 6SN7 (Driver), 1 x 6SL7 (Input),
2 x 5AR4 (Rectifier).
(Units prior to 2011 used 5U4 rectifier tubes.)
- Output Power @ 1Khz with 5 dB FeedBack in SINGLE-ENDED: 11 Watts @ 3% THD
- Output Power @ 1Khz with 5 dB FeedBack in PUSH-PULL: 24 Watts @ 1.5% THD
- Frequency Response with 5 dB FB in SINGLE-ENDED: 15 Hz - 15 Khz ±0.5 dB (measured at 5 watts)
- Frequency Response with 5 dB FB in PUSH-PULL: 10 Hz - 20 Khz ±0.5 dB
- GAIN SE Mode 0dB Feedback Setting: 30 dB
- GAIN SE Mode 10dB Feedback Setting: 20 dB
- Input Sensitivity with 5db FB SINGLE ENDED: 700mV for Maximum Power
- Input Sensitivity with 5db FB PUSH-PULL: 450mV for Maximum Power
- Input Sensitivity with 5db FB SINGLE ENDED: 165mV for 1V output into 8 Ohms
- Input Sensitivity with 5db FB PUSH-PULL: 160mV for 1V output into 8 Ohms
- S/N Ratio: SINGLE ENDED: 83.5dB Ref. 1W; 2.83v//8 Ohms,20KHz BW; 5dB FB.
- S/N Ratio: PUSH-PULL: 85.4dB Ref. 1W; 2.83v//8 Ohms; 20KHz BW; 5dB FB.
- Dynamic Range: SINGLE ENDED: 94dB Ref. 3% THD; 20KHz BW; 5dB FB.
- Dynamic Range: PUSH-PULL: 99.5dB Ref. 1.5% THD; 20KHz BW; 5dB FB.
- Input Impedance: 100 kOhm, direct coupled.
- Optimum Speaker Load (switchable): 4 to 12 Ohm range appropriate for 4 & 8 Ohm speakers
- 12 to 20 Ohm range appropriate for 16 Ohm speakers
- Actual Output Impedance SINGLE ENDED: 2.25 Ohms
- Actual Output Impedance PUSH-PULL: 1.86 Ohms
- Damping Factor SINGLE ENDED: 3.5
- Damping Factor PUSH-PULL: 4.3
- Maximum Power Consumption: 240 Watts
- Mains Voltage Frequency: 50~ 60Hz
- Power transformer factory set for 100V, 120V or 220-240VAC operation
for original destination country's mains voltage.
- Operating Mains Voltage changeable with power transformer re-wiring and fuse value change.
- Mains Fuse 100-120VAC operation: MDA 3 Amp SLO-BLO Ceramic Time-Delay fuse
- Mains Fuse 220-240VAC operation: MDA 1.5 Amp SLO-BLO Ceramic Time-Delay fuse
- B+ Fuse: MDA 400 mA SLO-BLO Ceramic Time-Delay fuse
- Badge Illumination: Units produced before 7/2003 use 8V, 0.3A "Fuse-Lamp" 1/4" X 1 1/4"
- Serial numbers after NSEPP314 use LED illumination which probably won't burn out
- Dimensions: W= 8.5, D= 23, H= 9 inches, Including projecting controls and parts
- Minimum Mounting Surface Dimensions: Feet Footprint = W= 7.5" D= 18"
- Shipping Weight: 41 lbs. Each.
Specifications subject to change because they just might.