Glasshole bypass LFO tick

[danfrank]

Yes, IC4-A. Too bad it didn't work for you, it totally got rid of the  "tick tick tick" on my Glass hole. See attached pic on how I did it. 68k from ground to pin 2 of LM324 and 33nf between pis 1 & 2. Note that you have to take pin 2 of the TL074 out of the socket so it is no longer connected to ground. Pin 2 is now grounded through the 68k resistor. I also did what Madbean suggested and wire in and out jacks straight to the footswitch. I also shorted the traces on the PCB that originally went to the in and out jacks, since they aren't being used. I figured grounding them wouldn't hurt anything.
One more thing... The article you linked is the same one I was referring to but mine couldn't be downloaded, so thanks for linking it.

[NorthCoast]

Sorry for a hijack here - Dan, did you replace the single turn trimmers on your Glasshole with multi-turn trimmers? Those kind of look like Bourns 3266w? Did you need more precision, or?

Thanks!

[geetarm@n1]

Dan -

Ah - I wired it up wrong the first time - never lifted pin 2 out of the socket (among other mistakes with the resistor and at pin 5).   Thanks for the explanation and pic - that helped.   I connected it up properly and the result is as you expected - the tick tock is now completely gone!!   I'm not going to put as many exclamation points as this deserves, but believe me - I am ecstatic.   I've been just sitting here listing to it swoosh through a loud amp with the guitar turned off for the last 15 minutes and it's lulled me into a relaxed out state of mind - a sure sign of clean, smooth phasing.

Thanks to all for the help, the lessons and for the project itself Mr. Bean.     

[danfrank]

Sorry for a hijack here - Dan, did you replace the single turn trimmers on your Glasshole with multi-turn trimmers? Those kind of look like Bourns 3266w? Did you need more precision, or?

Thanks!

Hi!
I used the 10 turn trimmers because that's what I had on hand. This project is pretty easy to dial in. Set the brightness trimmer (1k) about halfway. The offset is the important one... Set the depth pot all the way CW, Feedback CCW and rate fairly slow so you can see the full "sweep" of the LED by the LDRs. Of course this has to be done in close to complete darkness so it helps to have a light on your multimeter. Set the "offset" trimmer (10k) so the LED gets very dim (almost off) but not all the way off. Then you can tweak the two trimmers to taste. I found that adjusting the offset so the LED doesn't turn all the way off is very important.

[danfrank]

Dan -

Ah - I wired it up wrong the first time - never lifted pin 2 out of the socket (among other mistakes with the resistor and at pin 5).   Thanks for the explanation and pic - that helped.   I connected it up properly and the result is as you expected - the tick tock is now completely gone!! 

One more thing but I think you have already realized this... Pin 5 of the TL074 remains grounded, so it stays as is, no modification to pin 5. Only pin 2 gets lifted off of ground by the 68k resistor.
On that pdf article, I think the referenced drawing is using a single supply where as the Glass Hole uses a split supply. That may cause confusion for some.

[NorthCoast]

Sorry for a hijack here - Dan, did you replace the single turn trimmers on your Glasshole with multi-turn trimmers? Those kind of look like Bourns 3266w? Did you need more precision, or?

Thanks!

Hi!
I used the 10 turn trimmers because that's what I had on hand. This project is pretty easy to dial in. Set the brightness trimmer (1k) about halfway. The offset is the important one... Set the depth pot all the way CW, Feedback CCW and rate fairly slow so you can see the full "sweep" of the LED by the LDRs. Of course this has to be done in close to complete darkness so it helps to have a light on your multimeter. Set the "offset" trimmer (10k) so the LED gets very dim (almost off) but not all the way off. Then you can tweak the two trimmers to taste. I found that adjusting the offset so the LED doesn't turn all the way off is very important.

Thank you!

[geetarm@n1]

Yes - and pin 5 turned out to be an easy place for me to ground that 68K resistor without flying its lead across other circuitry or working under the board.  So the cap and the resistor just rest on top of IC4 (whose pin 2 was bent up 45 degrees and then clipped short giving me a flat spot to mount the other side of the 68K and that leg of the capacitor.  Ended up looking pretty clean, I'm happy to say.

Thanks again for the tip, Dan

[orangetones]

Hey there.  I'm yet to fire mine up, but the last few posts here mention lm324, but the BOM lists TL074.  Are people using LM324?  I  have another post asking about substituting MC33074AP in as well.

[danfrank]

My mistake, I'll correct it to TLO74, which is what it should be.
LM324 should also work for IC4 but I did use TL074 in mine