Deep blue delay - how to introduce distortion near oscillation?

[spilla]

I've built a few dbd clones now. The first one I made had a really cool distorted sound when approaching  oscillation. The repeats on higher feedback settings would distort but it was very pleasing/musical. Unfortunately subsequent builds did not have the same effect. They still sounded great but did not behave like the first pedal.

I'd like to try and recreate that effect one my next dbd build. What components would I socket to play with the feedback/oscillation settings?

Cheers!

[anotherjim]

I don't know where the definitive schematic is so part ID's may differ.
A larger delay time pot value (>50k) allows longer maximum delay and more lo-fi sound.

Repeats feedback path from pin14. C17 (47n) removes treble, reducing the cap will let more highs back to repeat. Increasing C16 (22n) lets more lows repeat. R9 (5k1) reducing increases total feedback level.

Doing anything like the above to increase repeat level for distortion is difficult - it will just tend to make it go into runaway feedback sooner. Distorting just the feedback signal is an option that has been done on other designs, but I don't know any by name to tell you - usually involves clipping with diodes.

[spilla]

Thanks man, that's given me some of places to start. Cheers

[nocentelli]

usually involves clipping with diodes.

A pair of antiparallel clipping diodes from the wiper of the repeats pot to ground works well

[spilla]

usually involves clipping with diodes.

A pair of antiparallel clipping diodes from the wiper of the repeats pot to ground works well

Cheers. What clipping diodes would be best to use here? i've got a stash here i can try out, probably best to try a few hey?

[niektb]

[...]

Cheers. What clipping diodes would be best to use here? i've got a stash here i can try out, probably best to try a few hey?

Just start with 2 1N4148s, but you could also try LEDs or anything. Doesn't matter too much