gain sections

Here are my notebook sketches, showing more or less what I want to do with the gain sections.  This doesn't show some of the surrounding bits such as the bypass relays.  My amp will have two "type F+", in positions 1 and 3, with a single "type M" in between (and the bypass switches allow any combination to be enabled, from none to all three in series, but always in the same fixed ordering).

I've drawn dashed lines to separate the portions of the circuits which are essentially direct copies of their namesakes (based upon public-domain schematics), from the supporting portions designed by me ("BWK-M").  (Take care to distinguish these dashed lines, from the ones representing conjoined dual controls such as pots and switches: I should have made them more different.)

The component values in the BWK-M portions, in many cases, are just my initial guesstimates.  These values "should work" to at least produce sound, but no doubt much adjustment will be needed once there is a working prototype.