Sparklehorn Delay Signal Bleeding through

[claytushaywood]

I just noticed my sparklehorn build has delay signal bleeding through when the overdrive portion is on and the delay is bypassed.  the mix knob in the delay section effects the sound of the overdrive too.  the delay bleeding through is pretty quiet in volume.  You cant hear it unless the mix knob is at noon or over, but that's through a pretty quiet amp.

Since the circuit is working perfectly besides that I'm wondering where to start.  My wiring is pretty darn neat.  Maybe the 1uf caps in the bypass of the delay?

[madbean]

What's happening is that the OD is traveling through the FDBK pot just a tiny bit when you have that Mix knob up. You could turn the FDBK and MIX knobs all the way down to have just OD without any bleed-through but then, of course, you have to reset them when the delay is on. This is kind of the compromise between having the two circuits combined AND have the tails switching. If you do not care about tails, you could work around it by grounding lug 3 of the FDBK or MIX pot when the delay is bypassed (using the free column of lugs on the Delay 3PDT).

A more idealized design would incorporate some kind of gate that would shut the delay line down after some period of time when it is bypassed. But, that is kinda way beyond the scope of this project.

[m-Kresol]

thanks for clarifying. I have the same effect and was wondering if it was supposed to be that way

[claytushaywood]

What's happening is that the OD is traveling through the FDBK pot just a tiny bit when you have that Mix knob up. You could turn the FDBK and MIX knobs all the way down to have just OD without any bleed-through but then, of course, you have to reset them when the delay is on. This is kind of the compromise between having the two circuits combined AND have the tails switching. If you do not care about tails, you could work around it by grounding lug 3 of the FDBK or MIX pot when the delay is bypassed (using the free column of lugs on the Delay 3PDT).

I mean I can hear it when the mix knob is at halfway.  But ok, I dont care about tails.  So Could I do something like run mix pot 3 to the middle rows bottom lug of the 3pdt (which are unused on your wiring diagram) and then just tap a ground and put it in the middle row's middle lug?  so that when the delay is bypassed it just makes contact with ground?  anything else in there that I should know?

A more idealized design would incorporate some kind of gate that would shut the delay line down after some period of time when it is bypassed. But, that is kinda way beyond the scope of this project.

[madbean]

Let's do this:
Remove the wires from the PCB and jumper your BYP pads to get rid of the Tails wiring. Ideally you would also want to remove R8 and jumper C8 but that is not critical. It will still work with those in place so don't worry about it.
Take the two wires you had connected to the BYP pads and do the following - remove R18 from the PCB. Solder one wire into one of the R18 pads. Solder R18 to the other wire and then the free end of R18 back to the remaining R18 pad (keep this under the board for cleanliness).

The end result is just shifting the bypass from "soft" to "hard". Now when you hit the footswitch, the delay signal is completely removed.

[claytushaywood]

Let's do this:
Remove the wires from the PCB and jumper your BYP pads to get rid of the Tails wiring. Ideally you would also want to remove R8 and jumper C8 but that is not critical. It will still work with those in place so don't worry about it.
Take the two wires you had connected to the BYP pads and do the following - remove R18 from the PCB. Solder one wire into one of the R18 pads. Solder R18 to the other wire and then the free end of R18 back to the remaining R18 pad (keep this under the board for cleanliness).

The end result is just shifting the bypass from "soft" to "hard". Now when you hit the footswitch, the delay signal is completely removed.

thanks!  am i going to need to do anything about popping with this bypass method?