calibrating bbds

[fogwolf]

I recently built a dual-delay line chorus effect (a Boss DC-2 clone)and calibrated each BBD line with an oscilloscope. For each line I put a 10kHz sine wave into the effect and tweaked each delay line's respective trimmer until I got the sine wave out of that delay line to maximum amplitude, but it never really clipped at any trimmer setting - it would just get really "blurry" towards either extreme of the trimmer (what seemed best to me was somewhere around midpoint range on the trimmers), and with a higher signal sine at the input it would get a little misshapen at certain spots on the trimmer, but not clipped and not at the max amplitude either.  Periodically even the stable sine wave I'd get would get a little blurry, probably from the LFO. I was surprised that I got the same "blurriness" or what not as I turned the trimmers down as when I turned them up. Guess I expected the peaks and lows to clip/square off as I turned the trimmer CW but that's now what I saw (like I said, never really saw it clip at all, just kind of warp, but at a lower amplitude).

Anyway, I'm pretty sure they're good, but this is the first time I've built or calibrated a chorus/BBD effect. If I hadn't done a good job of setting it up I'd get audible distortion, right? How do I know I'm getting the most headroom though - just by my ears? It's a pretty subtle chorus effect anyway, but it does sound good to me, just want to make sure I'm getting as much as I can out of those chips.

Thanks!

[Mark Hammer]

The DC-2 is actually a very robust chorus.  It can sound subtle because with one BBD always sharp and the other always flat, you never really get that characteristic pitch-wobble that happens when you have only one BBD falling behind then speeding up, just to fall behind again.

I suppose the easiest way to know it is set up in a perceptually satisfying way is insert a break (e.g., by lifting one end of a critical mixing resistor) for one delay path so that you only hear clean plus the other delay path.  IN other words, turn it briefly into a "classic" chorus.

But it's a nice sound, isn't it?

[fogwolf]

Thanks for the tip. I was thinking isolating them would be the best way to do it by ear.

It does sound great! Just want to make sure it couldn't sound even be better