SET recommendations

[gingertube]

ALF,
I see you are in Melbourne. Give Hugh Dean (AKSA) a call. He and a fellow in Mt Gambier have developed a Parafeed KT88 SET Amp. He can probably help with a schematic and local parts sources.
Cheers,
Ian (in South OZ)

Else there is this thread
SE KT88 Amp

[Sherman]

Originally posted by Bas Horneman
... And either 2 filament supplies or a filament supply that switches in the right voltage dropping resistor. Then ofcourse a seperate cathode resistor for the 300B and the KT88. The rest stays the same.

... The 300B needs more drive than a KT88. So when in 300B mode you won't be able to get the full power...but who cares. One could use that for certain types of music or late night listening. And switch in the KT88 for parties.

Maybe use a 12.6V filament trafo and switch between separate voltage regulators to supply either the 5V or 6.3V depending on the tube being used at the moment.

I'm sure that someone could sit down and draw a schematic to allow full output with either tube but without switching things in the driver stage you'll only optimize for one or the other.

A KT88 can be driven with 32-33V swing, more than double (IIRC) that for the 300B. Maybe set up to drive the 300B to full output and use less of the volume control for the KT88? Or as BAS says, you won't get full output from the 300B if the driver is optimized for the KT88.