Thomas organ guts for amp build?


2016-04-03 4:49 am
Hi! just joined! ok.. I salvaged the audio out of a thompson californian organ for guitar amp build., 2 12's ,the amp, a wire wound reverb unit and misc . If I can hack the amp for the input.(no luck on getting a schematic..) lots of wires going in it, power, headphone, aux.input.who knows what else.. Im hoping just tapping the volume control will do it. Also thinking it may have had a pre amp somwhere. Dont know.. any advice on that be nice. Curious about the reverb unit. Thinking of incorperating it in the build to find out what interesting sound effect one could get. Question is where to place it in the circut. Ahead the amp or after? I think the amp is stereo input, has R-L aux input, dual stacked pots on volume .., output for two speakers.(it had two speakers, diff.color wire for each one.) Im guessing the reverb is after amp? Placed between amp and speaker with a switch to direct output straight to speaker or go thru reverb? Thank you, harpo.
Last edited by a moderator:
Reverb goes between the pre-amp and the power amp. It can't handle the current that goes to a speaker.

EDIT: To expand on that a bit: There will be probably be a special 'reverb driver' stage (which might include a small transformer) somewhere after the first pre-amp stage, and another stage to recover the reverb signal and mix it back in with the straight through (or 'dry') signal before it goes to the power amp.
Last edited: