The Manley Ichiban and 500 watt, later known as 600 watt monoblocks, were built at the old VTL factory back before the Manley-VTL split-up that took place in 1993. They were at the time Manley's flagship models in the Designer's Reference Series. Both were 12-output tube designs. The Ichibans were triode strapped for about 200 watts output power (hence the smaller output transformer) and were found in both EL34 and KT90 tube complements. KT90's first showed up in 1990. The 500's or 600's were ultra-linear configured (with a much bigger output tranny) and used either GE 6550A's in the 500's before 1990 or KT90's in the 600's after 1990. The Input tube was always the 12AT7A or 6201. Some early models used the 12BH7A for driver tubes although most of the actual production models used 6350 driver tubes. Those two tube types have the grids and cathodes swapped on the pinout so make a big note that the 6350 and the 12BH7A are NOT interchangeable without reworking the circuit board!
Manley Ichibans sported solid Paduk wooden sides while the 500/600's had welded powdercoated steel side-members. Cool features of these amplifiers included the adjustable "slope" and "feedback" controls that allow the user to select different feedback capacitive and resistive values respectively. Also handy were the front panel mounted bias readout tipjacks and tube readout selector even though one still had to address the top deck of the amplifier to make the actual bias adjustments. See here how to do that. Many of the later Manley 600's and ICHIBANs had MIT-Multicaps. And some of them even had TRIODE / TETRODE switches. But none of them really ever got a proper owner's manual other than the generic info that was part of the VTL Book.
We still do perform warranty service on these old monsters, so if you need help with yours, please get in touch.
Guts view, underside audio chassis showing tube location
Note for biasing: there are two 20 Ohms resistors in parallel which give 10 Ohms total value as the cathode resistor.
Rear view of Manley Reference 500.
Blue binding post indicates around 1988 vintage, maybe early 1989.
Front view of Manley Ichiban. Manley Ichiban has no gap between upper and lower chassis faceplates.
- Driver High current double 6350
- Input l x 12AT7WA
- Audio chassis on top, power supply chassis on bottom
- The IEC detachable power cord is in the MIDDLE of the lower (power supply) chassis.
- Input sensitivity: 0.750V
- Input Impedance: 100 kOhm
- Output load impedance: Factory set for 5 Ohms nominal
- RCA Unbalanced input (sometimes had paralleled XLR connector)
- Front Panel bias measurement and adjust
- Mercury Magnetics power & output transformers
- S/N ratio: -80 dB probably
- Power consumption: enough to occasionally trip circuit breakers on turn-on
- Large filter / reservoir capacitors
- 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: bigger than a bread box
Each Chassis: 19" wide x 10" deep x 8.5" tall
The integral rack that holds the power supply on top of the audio chassis is 21" tall
That nets out to 19" wide x 10" deep x 21" tall per channel.
- Shipping weight: More than I can lift.
Specifications subject to change because they just might.
There was never any manual for the Ref 600 or Ichiban, but look here for biasing info.