FV-1 Delay Freakout/Havoc Switch

DougACB

New member
Hi folks,

First post here! Currently working through the design process with a friend of mine for a customized delay build. The hangup I'm stuck on is focused around how the potentiometers interact with the FV-1 program.

His requests are a delay with pitch shifting options on the repeats, exp pedal control for the delay time, and a momentary freakout switch (max feedback) for oscillation.

The Octagon is the basis I wish to start from, as it already has the pitch delay setting as well as lots of other modes to play with. It is also compatible with an expression pedal as documented in this thread:


With the design coming from Mad Bean:


I have read a few threads about adding a freakout/havoc switch to analog delays, with the momentary footswitch being tied to the feedback pot with a trim pot, allowing the feedback resistance value to be changed when the footswitch is pressed down, as documented here:


Looking at the circuit for the Octagon, while the delay is controlled by the program in the FV-1 chip, it is still influenced/controlled by the position of the potentiometers (in this case, B100K pots). Would using a trim pot and momentary switch to change the resistance signal to the program not change the feedback coming from the delay? I would think that it should work but all of the threads around feedback switches are focused on analog delay builds.

I have a good handle on the analog stuff but the world of digital fx is certainly above my expertise. If this isn't an option without making changes with SpinCAD then I will pursue a more convoluted method of adding pitch shifting etc to an analog delay architecture.

Thanks!
Doug
 
You can use a switch to instantly increase the Feedback control to maximum, but you'll never get more feedback than you have with the control turned all the way up.

If the feedback pot at maximum isn't enough you'll have to add a feedback path around the FV-1 IC.
 
Thanks for the reply, Robert. It's good to know the logic is sound, but whether or not the delay will oscillate remains to be seen. Being a digital delay I am expecting the max feedback setting will just cause the delay to repeat infinitly. I recall seeing in a Hydra thread that max feedback would not oscillate that circuit. The fix was adding a clipping stage to the wet output of the FV-1 to simulate an analog delay oscillating.

Adding a feedback path around the FV-1 is an interesting idea. It would be fun to cram a simple analog delay into the box with the sole function of providing the oscillation when the switch is pressed, but that seems overkill. Would the feedback path be as simple as a few jumpers to bring signal back to the front of the circuit, or would it be more involved than that?

Cheers
Doug

Edit - quickly realized that the feedback path idea as I speculated above has a lot of issues... going to keep digging
 
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