"oscillators are not completely silent once a note has been played"

Hi all, so I finally got my MIDIbox SID playing notes yesterday, which was quite exciting, but I did notice that when I pressed a key, after KEY OFF I could still hear the note, albeit much quieter.  Here’s some video I shot with the issue:

 

Is this what http://www.ucapps.de/midibox_sid_manual_ki.html is referring to when it says “oscillators are not completely silent once a note has been played”? And when it says its a bug, does that mean all SID 6580 chips do it, or that its random?

Note: I haven’t connected Audio In to ground, but I assuming not doing that results in noise or a hum and not notes.

Yes, this is a bug of the SID chip itself, they all do it. I usually run my MB SID through a noise gate.

1 Like

Jaytee, will any basic noise gate pedal work? Is there any unwanted side effects from using it?

I use a software gate but yes, they’re all basically equal for this purpose. The downside is some loss of dynamic control. In a mix you won’t likely notice anything, but solo, you might hear the signal getting turned on and off by the gate. It’s a trade off between that and the VCA leakage.

On 3/13/2017 at 4:16 PM, jaytee said:

Yes, this is a bug of the SID chip itself, they all do it. I usually run my MB SID through a noise gate.

I don’t recall this from my youth when using an actual C64… is it just that I wasn’t able to amplify it enough back then or were there software tricks used to silence it?

There may be software tricks to get around it; I think it’s somewhat related to the ADSR bug, so maybe the same workarounds apply?

If you have a stereo MBSID, see this thread for a DIY stereo noise gate solution:

< base_url >/topic/18139-mb6582-with-diy-noise-gate/?do=embed