Clicking noise when changing certain programs (pot)

Algorithm development and general DSP issues

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zandercircuitry
Posts: 4
Joined: Thu Jun 20, 2019 3:07 am

Clicking noise when changing certain programs (pot)

Post by zandercircuitry »

Hoping this is the best place to ask!

Ive been developing programs in SpinCAD (I know, not here, but the forum doesn't exist anymore) for a single circuit board that allows me to incorporate tap/midi/preset etc

To date I have a modulation, delay and reverb set of programs

We use a potentiometer for the program selector instead of a switch

I've noticed on the delay and reverb, when changing programs there's a static 'click' kind of sound that isn't present on the modulation programs. It's present on the delay and VERY present on the reverbs. On its own this wouldn't be too much of a problem, but because we've incorporated presets into the board, whenever you change a preset that moves to a different program, the click happens.

Any ideas what could be the culprit here? Not sure if it's something I could tweak in the spinasm code I can export from SpinCAD?

As far as I can tell, the static click isn't ringing out/repeating through the delay or the reverb, but is affected by the passive tone control that's after the spin circuit

Any ideas greatly appreciated as I'm kind of stumped!
Digital Larry
Posts: 338
Joined: Mon Nov 12, 2012 1:12 pm
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Re: Clicking noise when changing certain programs (pot)

Post by Digital Larry »

I spend more time in the DSP section of diystompboxes.com than I do over here, so to the extent that I'm going to support SpinCAD, that's the place to ask. Of course, SpinCAD just creates SpinASM, so you should be able to get some level of answers here by just posting your code here. I haven't even used SpinCAD myself for a long time but I just started doing so again as I want to get a pedal working for my bedroom setup. I don't need another modeler.

One thing that comes to mind is that some reference programs I found here (i.e. knowledge base, code examples, etc.) have a mysterious offset at the final output, as I remember, something like a

SOF 1.0, 0.02

Frank would have to weigh in but I recall that this was a workaround for a mfg issue with the earliest FV-1s. So, switching between a patch that has that and one that doesn't would cause a click.
ice-nine
Posts: 192
Joined: Thu May 24, 2012 9:03 am

Re: Clicking noise when changing certain programs (pot)

Post by ice-nine »

Digital Larry wrote: Mon Jun 20, 2022 9:04 am I spend more time in the DSP section of diystompboxes.com than I do over here, so to the extent that I'm going to support SpinCAD, that's the place to ask. Of course, SpinCAD just creates SpinASM, so you should be able to get some level of answers here by just posting your code here. I haven't even used SpinCAD myself for a long time but I just started doing so again as I want to get a pedal working for my bedroom setup. I don't need another modeler.

One thing that comes to mind is that some reference programs I found here (i.e. knowledge base, code examples, etc.) have a mysterious offset at the final output, as I remember, something like a

SOF 1.0, 0.02

Frank would have to weigh in but I recall that this was a workaround for a mfg issue with the earliest FV-1s. So, switching between a patch that has that and one that doesn't would cause a click.
Larry, those offsets in the Spin examples were to do with a DC offset problem Left/right outputs in the very first pre production FV-1 chips. The final production FV-1 were rectified. A click when changing programs is very likely a DC difference and should easily be found by checking the input and output coding.
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