Dwell pot on reverb input

[überfuzz]

I'd like to try and add dwell to a reverb circuit. It's kind of vague for me. It seems to be alight weight mod. How do I determine proper resistor/pot sizes? The circuit got the resistor values shown in the attached file, 470k to grid node and 2.2M down to ground. I used European symbols, much easier to draw in open office.

[Chuck H]

It would help if we knew the rest of the circuit to put the existing values in context. 2M pots are available, but possibly a bit clunky feeling and only available in linear taper, it might be better to use a 220k in place of the 470k resistor and a 1M pot in place of the 2.2M resistor. similar ratio and voltage division. 1M pots are readily available in audio taper and probably a better match for the circuit impedance so should make for a more intuitive feeling adjustment. This is almost surely fine but I can't be certain without seeing the circuit in context. Even a 1M pot may be clunky feeling and should be even smaller if possible or maybe the existing 470k resistor value is critical making value changes impractical anyway. Can you show us the rest of the schematic? Or at least everything from the previous amplifier stage to the reverb input?

[überfuzz]

Hmm, I see that my drawing don't match my schematic... I'm not 100% on your idea, but you're right about the values I guess.

High ohmic grid resistor to ground with the potentiometer wiper on the same node. This would be on the reverb driver stage. The 470k, or 220k as you suggest, in series with the potentiometer down to ground. I guess I just have to fiddle around with this until I found something I like, or just scrap it all together.

Thanks!

[Mark Hammer]

We need to know what amp this for. Dwell pots simply set how hard the springs are smacked. That can be done by aatenuating the output of a fixed-gain stage, but it could also be done by using a pot to vary the gain of the driver stage. So, what are you looking at?

[Chuck H]

Uber, my point was that we don't know what's possible without seeing how the posted values relate to the surrounding circuits. Even if what you posted isn't strictly correct this still applies to whatever IS correct.

Simply experimenting until something works can be a long road to a place you didn't want to go. Knowing is better than guessing and we can't know unless the operational circumstances are seen by people that can properly interpret them. Just tryin' stuff could lead to loading of the dry signal or limiting of the reverbs overall output. Possibly both or at worst, instability that then needs to be accounted for. Not to mention all the damage and potential for hasty, cold or dirty solder joints that result from prolonged experimenting. Better to bite the bullet and refine a schematic to demonstrate for a proper evaluation of your original post.

JM2C

[Jazz P Bass]

IF the reverb circuit is similar to a Fender Twin, the 1 meg resistor to ground on the input grid could simply be replaced with a 1 meg potentiometer with the wiper to the grid.

[überfuzz]

I have an other thread thatsort of umbrellas this thread. Vibroluxish build I think it's easier to keep all post related to that amp in that thread.