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previous: Mike D. This month I am restoring an old Ha... -- 9/10/1998 10:53 AM

Re: Adding Reverb to combo amp

9/11/1998 9:36 AM
niek	Re: Adding Reverb to combo amp Hi, I have been thinking about the same reverb mod to my Champ. I think you should be fine with the reverb level. Since the signal out of the tank is so small you can use a high value (470k) resistor to get a decent amount of gain. Use 1k5 for the cathode to stay in a 'clean' region. You can mix at the power tube, an EL 84 doesn't need much input signal. Use a big enough resistor between your reverb output pot an the grid resistor of the EL84 to have some buffering (470 K or bigger should do). Maybe you should take a peek a the the Traynor YGM-4 schematic (http://www.lynx.bc.ca/~jc/traynor.html). To prevent oscillation I would put a lowpass filter before the tank. With SE amps without neg . feedback you should be a bit careful but it's usually the higher frequencies that do it. I'd choose a 3 kHz cutoff before your tank. Your tankis a sort of positive feedback. Please keep me informed ! Good luck, Niek

9/11/1998 9:36 AM

niek

Re: Adding Reverb to combo amp

Hi,

I have been thinking about the same reverb mod to my Champ. I think you should be fine with the reverb level.

Since the signal out of the tank is so small you can use a high value (470k) resistor to get a decent amount of gain. Use 1k5 for the cathode to stay in a 'clean' region.

You can mix at the power tube, an EL 84 doesn't need much input signal. Use a big enough resistor between your reverb output pot an the grid resistor of the EL84 to have some buffering (470 K or bigger should do). Maybe you should take a peek a the the Traynor YGM-4 schematic (http://www.lynx.bc.ca/~jc/traynor.html).

To prevent oscillation I would put a lowpass filter before the tank. With SE amps without neg . feedback you should be a bit careful but it's usually the higher frequencies that do it. I'd choose a 3 kHz cutoff before your tank. Your tankis a sort of positive feedback.

Please keep me informed !

Good luck,

Niek