Adding tails to delay

[Michael2]

Hi all,

Trying to build a tails add-on for a Fuzzdog Analog-Like delay. But with a loop/splitter I have some slight phase issues. Is it possible to add a footswitch somewhere in this schematic to bypass the signal that feeds the delay but does not bypass the dry signal? Would that be a good idea? And what would be a good spot to do that?

[Kipper4]

[Michael2]

Thank you!

Does this mean that placing a momentary switch before R4 in the Fuzzdog schem is enough?

[Michael2]

Hmm...a bypass switch before R4 gives the opposite of what I want, it cancels out the dry signal. The wet signal stays on. Tried it with a momentary and a latching switch. I have the feeling it takes more than just adding a switch there?

[Michael2]

I figured it out. The switch needs to go before C6. As always reading properly is 99% of making the task done. Thanks again Kipper for posting the schematics, you are the hero of the day!

[Kipper4]

switch goes at your R10
ensure the off side of the switch goes to Vb V/2

[Michael2]

Ah, okay. I placed it right before C6, the 1uf cap and that works except now that I wired everything up it gives a ground "plop" when I engage the delay (even without the on/off led). Will it fix that if I place it at R10 as you say?

[Kipper4]

Did you wire the switch to 4v5 when the tails are off.
Otherwise you will get a switch pop.
Keeping the off at 4v5 should stop this,  if the tails switch is on IC3-A gets its 4v5 from the output of IC2-A (switch lug 1)
If the tails switch is off IC3-A gets its bias 4v5 from the switch lug3  (ref my drawing.)

[Michael2]

Haaaa, thanks, I wired it to IC2, now I understand what I did wrong. 
I now wired it to pin 2 of the PT2399 chip which is correct for 4,5 v right? The pop is totally gone. Only problem that arises now is that I hear a faint delay signal coming through when the delay is bypassed. Is this common?

[Michael2]

Wait, in your schematics it is mentioned it needs to be a momentary switch, I used a latching 3pDT (to accommodate an on/off led also). Does that makes the delay bleeding through in bypass mode? Sorry for all my questions, I'm still a newbie but eager to learn. Thanks for helping me.

[Kipper4]

Yep sorry the switch needs t be before your c6. The schematic you posted.
Momentary or latching shouldn't matter.
Somewhere here is a diagram for anti pop led switching.
Not sure why your getting bleed.

[Michael2]

Cool, no problem, I will wire that lead back before c6 then, it will surprise me if it will solve the bleed but hopefully it does.
There is no led pop since the VB is where it should be. Thanks again!

[Kipper4]

The Vb on the switch keeps the c6 cap at the same as if it was connected to your input op amps output in terms of DC.

The switch cuts off AC (insert instrument name here) to the pt2339 input
There should be no bleed.

Is it ok now?

[Michael2]

YEAH! It's working! No bleeds, no pops and no signal degradation whatsoever. This is fantastic. Thank you for all your help, just amazing!