Taming cascading delay

[gutsofgold]

I built a Rebote 2 with a cascading delay/feedback mod. It has a momentary switch and the delays build up so fast when its pushed. The volume builds up too and it literally is almost defeaning in seconds. It could easily destroy a speaker. I tried to add diodes on the Oscillation pot (which controls the feedback) - I added two 4148's in opposite direction on Lug 2 to Lug 1 which I also connected to ground. This had no effect and the oscillation is still very loud. Any ideas?

[flo]

Limiting diodes can also be connected:
- From lug 3 of 100k Repeat pot to GND: This limits the whole delay output for the repeat and wet pots.
OR
- From lug 2 (wiper) of 100k Repeat pot to GND: This limits the repeat signal that is feedback into the delay chip.

Regular Si diodes or LEDs or series combinations can be used for setting the maximum signal.

Because the feedback and oscillation is fickle and subtle to setup, I would change the 2.2k feedback resistor into something just below 10k (so that it just starts to oscillate with repeat pot at max and osc pot at min resistance) and use a 5k osc pot.

[gutsofgold]

So I added two anti-parallel silicon diodes from LUG 3 of the REPEATS pot to GND. It still oscillates into very loud volumes but if I can remember correctly it isn't as lound as it used to be. Is there a way to bring this down even more? I know germanium diodes would lower the volume more and sooner but I don't think it would make that much of a difference.

[flo]

Were you able to set the "oscillation" signal level that is "feedback" into the delay so that the repeat volume buildup is now slower than before?

Because oscillation depends on feedback, it is very hard to control. The volume will always try to max out.
I would:
- Set the "oscillation" resistance such that it just barely starts to oscillate and the volume of the repeats only very slowly builds-up. A 10-stroke precision trimpot would enable you to do that in a more controlled manner.
- Setup the "repeat" so that repeats only slowly fade-out.
- Actively control the momentary "oscillation" footswitch to let it to start oscillate, slowly building up the feedback repeats untill the volume starts to get too loud, and release the switch again to slowly letting the repeats fade out, etc.

With limiter diodes, the signal gets clipped harshly and the subjective sound perception of that is a loud signal.
Using germanium diodes brings the volume down to half the level. Se diodes have a forward voltage drop of 0.7V and Ge diodes (1N34A) around 0.3V:
http://www.reuk.co.uk/Germanium-Diodes.htm

[gutsofgold]

Well what I have to do is set the repeats knob to just below max, this is the only setting that the "oscillation" stompswitch works in. Then I set the speed at which the feedback builds with the oscillation knob. Even at the slower oscillation settings it still builds up to loud volume in about 3 or 4 seconds. I really only wanted this feature for the end of songs or in bridges where I could let is build up for a minute or two. If I were to let it build up that long the volume would definitely destroy my speakers.

Right now I do what you said in that I actively control the momentary footswitch. I press it in for say 2 seconds and I wind up with 3 or 4 seconds of craziness.