Tractor beam, high pitched sound when effect 0ff or on?

[Spenzerleehorton]

looking on pins 1-3 of the TL074 the waveform looks ok, on pins 5-7 waveform looks alright.
On pins 8-10 really fuzzy waveform.
with the effect off i get -6.12v on pin1, when i turn on its varies and jumps around.
attached is a picture of the mix fully CW to show what effect signal i'm getting

[Spenzerleehorton]

If my 22k array wasn't bussed could it cause this problem?

Or if the 10k array not isolated?

[Spenzerleehorton]

I'm going to order the proper 22k as my one was called "commoned" rather than bussed?
Need to find out what the difference is?

[Spenzerleehorton]

Ah I think I understand now, I need a 22k which consists of 3 separate resistors, where as what I have in all the resistors are connected!!
Hopefully this is the only error and I can get this sorted!!

[Spenzerleehorton]

To correct myself I need 2 x 10k isolated resistor arrays which are basically 4 x 10k in each.
The 22k is the bussed or commoned type with a dot at one end so you don't get it the wrong way round.
I've taken out both of what I've put in and have ordered the bourns types.
Pretty sure this was my error and this is what was giving wrong voltage readings.

[Spenzerleehorton]

ok parts arrived this morning, i've managed to change the 10k's and 22k arrays, wired back up with temp transistors which are not matched and i have phasing!!!
Just need to change transistors for matched 4 then change 1M pot for reverse taper then put back in case.
Only problem i have is a high whistling pitch that i need to get rid of?

[Spenzerleehorton]

The high pitch sound is there even when mix is set off CCW?

Any ideas anyone about how to sort this?
as i'm so close to getting this fully working, it sounds pretty good using the TL074, also the TLE2074 works fine as well but the high pitched sound is there all the time when effect is on?

[Spenzerleehorton]

Seems I'm totally on my own here!!!

Will check everything again.

[Spenzerleehorton]

feel pretty isolated here, with no help, both the Deathclaw and this tractor beam i'm having a hard time with and would really appreciate some help please.
This tractor beam i'm getting a high pitched frequency when the effect is off and when the effect is on, apart from that the pedal now works as it should.
could anyone point out which capacitor or what part of the circuit i will need to look at which addresses this high frequency interference please.

[Spenzerleehorton]

I have read that the opa2134 May be missing a cap to tame the top end?
And to try more modern opamp, 4558,5532,tl072 or tl082 to see if high end is attenuated due to these having a high end cap in them?
I maybe clutching at straws here but without any input I don't know.

[Spenzerleehorton]

right i've fixed it, anyone else who gets this issue of high frequency pitch somewhere around 5-8k change the charge pump on the switch pcb.
all sorted.

[Boba7]

Hey! Glad you got it working, and sorry there was not much help!

Yeah, charge pumps can be quite capricious sometimes...

[gordo]

Yeah, glad you got it working.  The nasty part is that there really isn't enough room to mount the charge pump in a socket.  Knock on wood but I think I've only had to chase my tail on one pump out of all the builds I've done.

And Boba7, it's a very good day when you can whip out "capricious" in a sentence so smoothly.  Well played.

[Boba7]

.
And Boba7, it's a very good day when you can whip out "capricious" in a sentence so smoothly.  Well played.

Haha in french (my language) it's a casual term and I couldnt think of another word