Clandestine sqeals like a pig

[Markus Kersius]

Build the clandestine preamp last night, and while testing it (not boxed yet), it emits a high oscillating pitch.
This occurs in every setting even with the volume all the way off.
Everything is correct regarding values, wiring and solderflow on the pads.
Even tried the in/output wires with shielded cable, but no improvement.
What's going on here?

 

[music6000]

Build the clandestine preamp last night, and while testing it (not boxed yet), it emits a high oscillating pitch.
This occurs in every setting even with the volume all the way off.
Everything is correct regarding values, wiring and solderflow on the pads.
Even tried the in/output wires with shielded cable, but no improvement.
What's going on here?

Did you use this with letter highlighted, IC100 - TC1044SCPA, If no S it will whine & squeal.
If you used 7660SCPA, If no S it will whine & squeal.

 

[Markus Kersius]

This is the actual ic.
I now have a lt1044 in it..
stopped the squeal, but the original tc1044s shouldn't be doing thisn right?

 

[music6000]

This is the actual ic.
I now have a lt1044 in it..
stopped the squeal, but the original tc1044s shouldn't be doing thisn right?
View attachment 22665

It says the correct part number but it's not the first time I've seen these fail!
I personally will only use 7660SCPAZ.
Do you have another working pedal with this part TC1044SCPA socketed in it!
If Yes, try swapping to rule out this part causing the issue!

 

[music6000]

I now have a lt1044 in it..

You mean an LT1054, It's better than TC1044SCPA but people don't want to pay for the extra coin!!!

Was the TC1044SCPA from Tayda??????????

 

[Markus Kersius]

You mean an LT1054, It's better than TC1044SCPA but people don't want to pay for the extra coin!!!

Was the TC1044SCPA from Tayda??????????

Thnx, the ic came with the kit from Musikding, never had problems with parts of them not functioning.
But no, it is a ltc1044 in it now.
I believe I did a vero build of a klon a while back and the ltc1044 was a left over from that

 

[music6000]

Thnx, the ic came with the kit from Musikding, never had problems with parts of them not functioning.
But no, it is a ltc1044 in it now.
I believe I did a vero build of a klon a while back and the ltc1044 was a left over from that

View attachment 22667


View attachment 22668

The OEM Klon Centaur uses the 7660SCPA.
Cool!, so the Circuit is now Working?

 

[Markus Kersius]

The OEM Klon Centaur uses the 7660SCPA.
Cool!, so the Circuit is now Working?

That's why the 1044 was a leftover I guess
The clandestine works OK, but even with no voltage doubler IC installed it works..
Makes me wonder if something else is not working as it should.
First ever pedalPCB which gave me a headscratch..
And I think it's pure user error and not to blame the parts
I'm just not good troubleshooter
I'm putting it aside for a while and doing a couple vero builds before tackling this one again.
Thnx for your replies and info!

 

[music6000]

With LTC1044 installed you should be getting around 17 to 18v at the D105 Diode circled in Red!
Trimmer should be adjusted to around 9 to 12v: