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previous: Blues Lyne Mark,Thanks for you... -- 9/29/1999 9:20 AM View Thread

Re: R.G., Question about Flanger / Vibrato

9/29/1999 1:26 PM
Mark HammerRe: R.G., Question about Flanger / Vibrato
"The problem is that with the pedal in bypass there was no sound. Did I miss something? "  
Nope, BOSS did, and I should have factored that in. Their switching arrangement uses a single FET to kick the delayed portion in and out of circuit, with the input buffer and output buffer/mixer always in circuit. Of course if you cancel the straight portion to get vibrato, and hit the "bypass" switch to cancel the effect, you WILL get nothing because neither delayed nor straight is being permitted to make it to the mixer.  
Yet one more reason why true bypass is preferred over expedient FET switching: when the circuit is bypassed, it's as if the effect wasn't there at all.  
Incidentally, the subtlety of the vibrato is a function if the very brief delay used for flanging. Up the clock cap value as suggested, and the delay should be long enough to produce more robust vibrato.  
If you were willing to forego the flanging features, you COULD adapt the unit to a vibrato unit with bypass that works. The electronic switching circuit is a flip-flop connected to only one FET so that it flips but doesn't flop. What you would need to do would be to insert an FET of the same type in the straight signal path (between the 47k resistor and the input to the op-amp), and wire it up to the other side of the flip-flop circuit. This would allow you to select between delayed OR straight, with the footswitch. If you want the flanging effect, you could use the toggle switch suggested in my last post to bypass the straight-signal FET. See some of the other flip-flop switching circuits for how to do this (e.g., posted schematics for the Slow Gear, OD-1, TS-10, etc.)

Blues Lyne Mark,Thanks for the... -- 9/29/1999 8:38 PM