Twin peaks tremolo

[Sensei Tim]

I’ve built the twin peaks tremolo (TPT) before using David’s o  band it worked fine but I’m having a heck of a time getting the vero version working.

The taplfo seems to be working. The tap led seems to flash and change when I adjust the depth, rate, symmetry and multiplier controls.

My problem is I can’t seem to bias the lfo properly.  If I do an audio probe I get signal on the ldrs but no matter what position I set the rotary switch to I can’t seem to get a signal at the output.

My led (d1) is light and I measure 1.8v across it so T1 should be outputting the proper voltage.

The only mod ive done is use a 50k trimmer instead of the 25k trimmernfor the offset.

Any suggestions for what to look at? Could the lfo chip be dead?

[Sensei Tim]

Moreninfo:  when I use my audio signal generator I can get a signal on the output but when I connect my guitar (lower voltage signal) I get nothing.

[scimitar]

If you have got the led flashing then the TAPLFO chip must be working... I have built this successfully so if you need voltage checks I should be able to get them - have you heatshrinked the LDR/LED to prevent ambient light getting in?

[Sensei Tim]

Yeah that's why i'm a bit confused.

I'm using VTL5C1's from smallbear.

when i put the meter on the LDR portion i can hear the volume being modulated. I'm starting to wonder if it might be  the TL074 that's sketchy

[Sensei Tim]

Update:  swapped the tl074 and now sound passes, but there are some other quirks.