NURSE QUACKY.... AAARGHH!!!

[Barcode80]

now we begin debugging unsuccessful build number 3 in a row. i used the perf layout at ROG to build a nurse quacky. i get signal, and i get a significant bass boost (ROG schem is hard wired in bass mode), but i get no envelope effect and the pots do nothing. could this be due to a bad IC? i've tried a 4558 and a tl072, both with the same results. i have also tried a 2n3904 and a 2n2222 in the tranny spot. one of the diodes lights up, but only one. i'm not sure if they are both supposed to or not. i socketed the tranny and the IC, so overheating is not an issue. my solder job is near perfect, very pcb-esque. i'm even gonna post pics no matter whether i get the pedal working or not, just to show off the immaculate solder job. so anyway, any ideas?

[JimRayden]

Well, it has been almost three years since I built this  but as I remember only one led is supposed to light up.

Check for errors around or in your sensitivity pot, it might not be passing signal to the envelope follower, thus not changing the filter response.

---------
Jimbo

[Mark Hammer]

One should light up all the time (the biasing LED on the input pin to the op-amp), and the other should light up when you strum.  You SHOULD get a couple of volts AC output on that op-amp.  If not then you've got something misconnected or you simply need a heftier gain to generate a suitable envelope voltage.  Could be the dreaded undersignalitis!

Of course, if the op-amp and transistor are approriate and appropriately installed, then tweaking the trimpot ought to shift the filter frequency, so it is possible there may be an issue with transistor pinouts and such. So...

1) measure the AC voltage along the envelope follower path.
2) Confirm the pinout of your transistor

[Barcode80]

i've confirmed the pinouts, but i'm too new to know what you mean by the follower path. the second LED is not lighting up at all, so that might be a problem. i've checked the LED, and it is functioning. but since it isn't flickering when i play, i guess i'm not getting enough voltage for some reason.

[oldrocker]

Make sure the sensitivity pot is turned up when you're strumming.  Input goes to lug 3 and out lug 2 to the 47k and from there to the .01uF.  Is the LED installed right coming from the opamp?
Also I don't know if this means anything but I used yellow LEDS instead of the red ones.  It seems to work better if you're using a TL072.