Just found this forum... 
My current guitar amp is a stock 2x6BQ5 PA amp (Keil) that cost seven bucks at a thrift store, powering a 15" Blue Jensen from a Baldwin church organ, all in a Traynor enclosure. The preamp has an EF85 on one mic input, so the signal from my humbuckers is immmediate dirt and the sustain is forever.
I didn't use the three-channel Baldwin amp (2 x 2 and 1 x 4 6BQs) because it is massive and needs three speakers.
I retired a Thomas organ 2 x 6L6GC due to poor stock preamp and more expensive power tubes.
My question is... anybody got a an idea for adding my 16" Hammond spring reverb unit to the Keil?
My current guitar amp is a stock 2x6BQ5 PA amp (Keil) that cost seven bucks at a thrift store, powering a 15" Blue Jensen from a Baldwin church organ, all in a Traynor enclosure. The preamp has an EF85 on one mic input, so the signal from my humbuckers is immmediate dirt and the sustain is forever.
I didn't use the three-channel Baldwin amp (2 x 2 and 1 x 4 6BQs) because it is massive and needs three speakers.
I retired a Thomas organ 2 x 6L6GC due to poor stock preamp and more expensive power tubes.
My question is... anybody got a an idea for adding my 16" Hammond spring reverb unit to the Keil?
Hi OldTubes,
Well, you have to drive the spring with something like a 12AU7 or 12AT7 through a transformer (step down), and amplify the signal with a 12AX7. Mix the output from the 12AX7 into the signal path and use a level control ("reverb"). The signal is "picked off" from the main signal after your inputs are mixed before any tone stage. Check out some amp schematics on the web for ideas.
-Chris
Well, you have to drive the spring with something like a 12AU7 or 12AT7 through a transformer (step down), and amplify the signal with a 12AX7. Mix the output from the 12AX7 into the signal path and use a level control ("reverb"). The signal is "picked off" from the main signal after your inputs are mixed before any tone stage. Check out some amp schematics on the web for ideas.
-Chris
Look at the schemo for a Fender Deluxe Reverb or for that matter most any tube amp with reverb. The signal is sampled out and reverbed then mixed back in. Fender would do this at the two ends of a 3 meg resistor. Check it out and steal the circuit.
The reverb itself requires a circuit to drive the reverb pan and a recovery amp to boost the feeble pan output back up to what is going on in the amp at that stage. Most Fenders use a small single ended amp to drive the pan with a transformer. The recovery stage is just a triode.
I think I just said the same thing CHris did.
Try the Mr Gearhead site for drawings.
The reverb itself requires a circuit to drive the reverb pan and a recovery amp to boost the feeble pan output back up to what is going on in the amp at that stage. Most Fenders use a small single ended amp to drive the pan with a transformer. The recovery stage is just a triode.
I think I just said the same thing CHris did.
Try the Mr Gearhead site for drawings.
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