'68 Reverbojet

[decent_rancher]

you could try removing C4.  Its basically the "ultra-high" or bright cap that isn't switchable/always on.   They likely used a Ceramic cap too,  so if you want to keep it you could try swapping it for a silver-mica and see if the helps.

Very interesting - thanks for this!

Any speaker recommendations? Also curious to know how different these are from the earlier 60s Jets.