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Full spec - last updated 16/09/06 00:46:24

 

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2 x 50W RMS output on 4 x EL34 or 4 x 6L6WGC. 2 x 42W RMS output on 4 x 5881 or 4 x 6L6WGB. Either channel adjustable for 4/8/16 ohms.
1/4" jack with variable attenuator for guitar changes.
Rhythm channel. Gain/Lo EQ/Hi EQ/Level. Switchable harmonic (or "brown tone") control to flip between smooth creamy sustain, or "hat on backwards" stuff.
Lead channel. Gain 1/Gain 2/Lo EQ/Hi EQ/Level. Gain 1 and 2 are linked to Master Volume 1 and 2, i.e. when MV1 is selected, Gain 1 is used. MV2 kicks in Gain 2 giving more variations. Or you can keep them the same.
Reverb/Effect/Master Volume 1/Master Volume 2. These are all foot switched. The reverb is internal, the effects loop is external - mono send, stereo return with fully adjustable levels. Power switch and standby switch. The standby switch does not turn off the HT, it reduces it from 430V to 250V to prolong output valve life.
2 x speaker jacks, stereo slave out, stereo slave in, mono effect send, stereo effect return, 2 x HT fuses, 1 x mains fuse, footswitch socket, 2 x impedance selectors, adjustable damping control.
Preamp heaters DC fed from regulated 12V supply. Power amp drivers fed from a MOSFET regulator for low noise. 4 x independently adjustable bias supplies.
Power amp 4 x 6L6WGB, Driver 2 x CV-4024 + 1 x CV-4004, Preamp 5 x CV-4004. Note CV-4024 is mil-spec 12AT7, CV-4004 is mil-spec 12AX7.

The variable input attenuator was a "must" for me when changing guitars, but seems missing on most amps. Plug in a Strat/Tele and set to 3 o'clock position. Get the right level of crunch/volume etc. It's going to overdrive a lot if you swap to a Gibson, or any guitar with humbuckers. Wind back to 11 o'clock. Humbucker sound - same crunch/volume without having to mess about with the gain controls.

Noise: Valve guitar amps are generally noisy, with some hum and hiss being present - especially when cranked up. A MOSFET regulator was used to provide all the high voltage requirements, except the output valves. Heaters on the smaller valves are all from a solid state regulated supply. 4 bias supplies are present to allow any mismatch in the output valves to be dialled out and this cancels any hum in the output stage.

Everyone who has played it has always made the initial comment about how quiet it is - until they hit that open A chord, heh heh heh....

Earlier, I made the comment it was an all-valve (almost) design. Apart from the obvious use of solid state in the power supplies, the effects loop buffering is solid state too. I couldn't see the point of using valves for loop buffering, when the loop is generally some type of analogue or digital solid state contraption.