SID chip filter distorting/clipping?

[jaytee]

I was running my sammichSID through some midi today and noticed that patches involving the filter seemed to introduce significant clipping/distortion.

I haven't done extensive testing, but it seems to happen at least with the LP filter, especially when the cutoff is turned down. Changing the patch to something else and then back seems to help for like five seconds. I am not even sure how to begin more extensive testing, any advice regarding that is appreciated.

I just underwent a move that involved shipping the sammichSID; I could believe that some damage was done. It just seems odd that both SID chips would undergo the exact same damage at the same time. As far as I know, the filters were fine before the move. Both chips are 8580 btw.

Am I missing something?

[Hawkeye]

Can you open it up and check for the socketed filter caps? See if they are still in place?

 

Many greets,

Peter

[jaytee]

All filter caps remain in place; I gave them a good little shove for good measure (and terrifyingly bent one over; seems fine though). Hmmmm... Now I seem to be getting the same clipping and distortion without the filter engaged. Always seems to be at the same two points in my MIDI sequence, although I can't understand why; there's nothing special about those notes that I can see. More investigation is necessary.

[jaytee]

Can't seem to duplicate the results noodling on a midi controller, which I suppose is comforting. I have no idea what's going on in this midi sequence that's causing the sammichSID to bug out though. I tried deleting the notes and adding them back; I tried changing the note value, I tried changing velocity. I hit the same notes elsewhere in the sequence with no problem. Grumble,

[Imp]

Sounds like there is some unintended cc-automation going on. Maybe your DAW caught some controller values while recording?

[jaytee]

Ok found the issue. sammichSID is not at fault, thank goodness. For some reason a bunch of garbage CC data got recorded into my sequence somehow. Thanks for the help; even if it was just helping me rule out my hardware as the issue! The CC causing my issue was 22, which controls waveforms. Turns out there's a bunch of CC garbage on a lot of others too, just none that affecting the sound in this sequence on this patch. At least I got to open up my sammich again!

[jaytee]

Imp, totally missed your response; you had it right on the nose. No idea how that automation got recorded, but it did. Thanks!