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The Manley 250 Watt Monoblock was produced between 1994 - 1997

The Manley 240/100 Old Billet Chassis was produced between 1997 - 1999

Manley 250 Watt Monoblock

Manley 240/100 Old Billet Chassis

Features & SpecificationsPhotosDownloads

A leading reviewer recently wrote the following about the Manley 250's: "In triode mode a pair of Manleys produces a remarkably three dimensional soundfield that is both convincing and seductive. When switched into tetrode mode, the Manleys have the brawn to deliver a full symphony orchestra directly into your living room." "When I listened through the same cut through the triode mode tube amps, I cried. Yup, tears ran down my cheeks while I bounced up and down, waving my arms, physically buffeted by the raw emotion of the music. Emotion- that essential component at the very core of great music. The Manleys pass through that emotional information, but the (solid-state amps) don't."

Tried and true: The Manley 500 and 250 Watt Monoblocks are our most powerful push-pull production-models. Both the circuit design and the selected componentry have been refined over years and years of development. Reliability that you can depend upon combined with musical accuracy and emotional authority is what these amplifiers promise- and deliver. They are able to switch operation modes allowing the listener to choose between the sonically seductive qualities of triode and the more powerful tetrode configuration. We use big, beefy reservoir capacitors in the high voltage supplies giving plenty of instant energy for dynamic performance of transient peaks and bass impact and weight which often exceeds that of rival solid-state amplifiers. We run high voltages on the plates of the output tubes but operate them at lower current which will result in their longer life.

To avoid a heavy power drain when the cold amplifier is first switched on, we conceived a "Soft-Start" mode which also functions as an "Ever-Warm" position allowing the amplifiers to be always warmed up for pleasurable listening. Although each output tube has its own bias-adjust. We carefully fit each amplifier with computer-batched tubes for optimum performance. The FEEDBACK control featured on the 500 watt model changes overall feedback which affects the gain and slew rate of the amplifier while the SLOPE control changes the super-sonic roll-off point allowing the user to optimize the amplifier-speaker interface. For more information about variable feedback, read Notes on Negative Feedback.

In our own in-house magnetics department, our team completely redesigned all of our output transformers in 1998 with the goal to reclaim that luscious rich mid-range of our vintage designs. We also specifically set out to achieve a deeper bottom register at higher power with lower distortion. Hours and hours of listening tests, measurements, and fine-tuning brought an exciting and stunning result to our ears. We hope you will agree. Welcome to the New Manley Reference highest powered amplifiers!

FAQ #250. What tubes should I get for my Manley 250's?

For the output tubes, we use the EL34EH (Russian), and have found these to be quite good. We sell them at $14/ea in quantities of 20 (two matched sets of ten). I have heard good things about the Svetlana and JJ EL34 but have not evaluated them. It's tough to evaluate the lifespan of a tube until it dies so we stick with what we know works and sounds good. The 6414 driver tube is a bit of an odball, with GE and Raytheon being the ones you will probably find (that's what we have here- $15/ea). The 12AT7 input tube is very common, and we use the EI version here ($15) which most audiophiles are fond of. I am personally a little afraid of untested "new old stock" tubes at high prices. There may be a reason they have been kicking around for 30 years.

Get the owner's manual for the Manley 250 Watt Monoblock and Manley 240/100 Old Billet Chassis Monoblock PDF.



Features and Specifications
Manley 250 Watt Monoblock and Manley 240/100 Old Billet Chassis Monoblock:

  • Vacuum tubes:
  • Output 10 x EL34G
  • Driver 2 x 6414
  • Input l x 12AT7WA
  • Output Power(tetrode): 350W
  • Output Power(triode): 230W
  • Input sensitivity: 1V nominal
  • Input Impedance RCA: 116 kOhm @ 1KHz
  • Input Impedance XLR: 270 kOhm @ 1KHz; 20 kOhms @ 20KHz; 38 kOhm @ 20Hz
  • Output load impedance: 5 Ohm
  • FLAT Freq. Response: 10 Hz - 30 KHz continuous
  • S/N ratio: -80 dB
  • Power consumption: 30 Watts in "Ever-Warm"
  • Balanced & Unbalanced inputs
  • Triode / Tetrode Switching
  • Soft-Start and Ever-Warm standby modes
  • Manley Precision dual-coil output transformer
  • Front panel bias measurement and adjust
  • Large filter / reservoir capacitors
  • Milled aluminum cabinetry provides rigid mounting
  • 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 Voltage Frequency:
  • Dimensions: W=19", D=13", H=7"
  • Shipping weight: 73 lbs. each


Manufacturer's Suggested Retail Price
  • Manley 250 Watt Monoblock Original Retail Price: $9,000 clams (USD $) per pair
  • Manley 240/100 Old Billet Chassis Monoblock Original Retail Price: $9,000 clams (USD $) per pair

Replaced by the Manley 250 Watt Monoblock