Hydra Delay - self-oscillation?

[gloomlord]

I’ve just finished putting the board together for the Hydra Delay. Sounds brilliant, especially with the addition of the clock module. Just wondering if it supposed to have the ability to go into self-oscillation?

 

[twebb6778]

Congrats on the build! I've found that it takes a little finesse to get it to self oscillate, only seems to want to do it with certain head combinations. I can't remember off the top of my head, but maybe someone else might be able to chime in.

 

[gloomlord]

Yes, since posting I’ve had a play and found it only self-oscillates with heads 2 and 4 engaged, but it’s not the craziest oscillation ever. Not that it matters much, I have other delays for that kind of silliness. I wonder if there’s a way to add a momentary feedback function. Not sure how that would work. This is my first foray into the FV1 realm!

 

[twebb6778]

Doesn't look like the schematic has been posted, but it should be as easy as using a momentary switch to short the feedback pot.

 

[gloomlord]

That’s what I’ve normally done in the PT2399 delays I’ve built, but wasn’t sure if it would work in the same way on the Hydra. Will do some experimenting.

 

[twebb6778]

Strictly speaking I don't think there's actually any signal going to the pot, but it should still have the same effect.

 

[Boba7]

Nope, it doesnt oscillate with only one head selected, so the usual momentary shorting the feedback pot will have little effect in those positions

 

[Boba7]

Here’s what I did with mine: https://forum.pedalpcb.com/threads/another-hydra-delay-with-a-tweak.2747/

 

[twebb6778]

That's a really neat idea! Might have to try it out on mine.

 

[gloomlord]

That sounds very interesting. How did you actually wire that up?

 

[Boba7]

That sounds very interesting. How did you actually wire that up?

Don't have the schematics with me, but I'll try to remember...
There should be an opamp buffer after the FV1 output that goes more or less directly to the repeat pot. I just put the Electra circuit between the buffer and the pot. Can't remember why I chose the Lovepedal JTM values, probably because the layout was small
I don't have the pedal anymore, but it sounded awesome!