Simultaneous Fixed and Cathode Bias power tubes

[ViperDoc]

I am an unapologetic fan of Carr Amps. Steve Carr makes a mighty fine combo.

I was researching the Slant 6V--a 40 W quad-6V6, 2-channel amp with reverb. The amp runs the 6V6 tubes in pairs--one pair with adjustable-fixed bias and the other pair with cathode bias. You can select between the pairs for the preferred bias type/sound in separate half-power modes. Or when running in full power mode, each pair uses its own bias circuit simultaneously.

Does anyone know of a clear schematic file for this amp? I found a pencil-drawn low-res version somewhere here that is very difficult to read.

Are there any other amps that share this design?

[roberto]

It comes from Mesa's Simulclass, where one pair was running cathode biased (in triode, in that case), while the other pair(s) in pentode fixed bias.
You can use that schematic as a starting point.

[ViperDoc]

Thanks, roberto!

[Stevem]

The Mesa schematic is a start, yes but his amp in question keeps all 4 tubes in Pentode mode.

Many of the CBS era Fender silverface high power amps used a underlying cathode biased output stage besides the normal fixed bias.

These amps don't have the ultimate punch of the fully fixed bias amps, but to me they have a very usable sweetness to them !

[ViperDoc]

Here's the schematic I found online:

7C5FF333-393E-436A-8532-039A46D24CEA.jpeg