Hello, just bought a used P12 on Reverb, have lusted after one of these for a while and finally took the plunge. So far I absolutely love it.
But I ran into an interesting issue that I could not find the answer to online, regarding the delay feedback behavior.
It seems that delay feedback does not act per delay line, but feeds back into all delay lines. For example, if you take a short percussive patch and use delay line 1 to do a 150ms delay, no feedback, and pan that to the left, you can hear a single tap in your left channel, as expected. If you then add delay line 2 with a 250 ms delay and pan it right (no feedback), you can hear a tap in the left channel followed by a tap in the right channel, as expected.
However, adding feedback to either delay line 1 or 2 seems to send the delayed signal through both delay lines, rather than just the one you have applied feedback to. Adding feedback on either tap individually causes the other taps to feed back, and depending on which tap the feedback is added to, sometimes the stereo field collapses or there are taps coming at odd times. Adding feedback to both taps just causes the feedback to kind of come right down the center, no stereo spread.
(This has nothing to do with delay pan BTW, panning just makes it easier to hear what's going on.)
What I would expect to happen is that adding feedback to a single delay line only feeds back that delay line, and adding feedback to a hard panned delay line would only result in more repeats of that delay, panned the same. But apparently it runs through all active delays or something, which seems odd and leads to some unexpected results.
Is this a known behavior? Hopefully I am explaining it well enough, it's simple to repro but kind of hard to describe until you hear it or play around with it.
I am using OS 1.4.0 btw. I didn't see anything in the release notes for the new OS related to this, so I didn't update, but I can do that if it'd help.
Either it's a bug, something is broken on my board, or I just don't understand how it works. Would be nice to know which it is
Thanks,
Dave
Edit: Adding feedback to ONLY delay line 2 (the 250ms delay) in the above example results in the proper ping pong behavior, where both taps repeat alternately left and right. However adding feedback to only #1 doesn't work, and does strange things. Why adding feedback to only #2 results in the taps from #1 to repeat is where I'm confused, but at least I can get the effect I'm after one way or another.