Sansamp GT2 squeal problems

[chemman]

Hi, I built the sansamp with tonepad.com layout with  TLC2262 in IC 2,3,4 and Tl072 in ic1. All the settings work but I have two problems.

-First there is a switch popping between amp switching (maybe normal because this switch moves Vb to different ics).
-Second there is a horrible squeal at high gain settings.

Things I tried.--
I shielded the input jack and in and out sansamp wires with braided shield and put a 47pf cap across input to ground with the squeal a little less but still enough to bug me like crazy. Also added 100uf across rails but no change so not power filtering prob

I am using no stomp switch for the pedal and I noticed that when I place my finger on the plastic of my insulated input jack the noise gets louder( hiss to a squeal depending on volume and gain settings). In addition when turning the gain knob I get a scratchy noise.   

On the 3c input jack I have the Signal, battery (-), and all grounds from the board and other components. Touching the plastic of the output jack doesn't make the hiss/squeal worse.

I love the sound of this pedal and maybe I am being to picky to eliminate most of the noise but I would like to combat it more. Is this radio interference ?


Thanks,
matt

[fxdfxd]

Hi

I've a kind of feedback too, and many others too. I think there's nothing that you can do to solve this pb, unfortunatly (but I whish I could be wrong)

-fx

[chemman]

That sucks.. Sounds great ne way with a noise supressor for high gain. Another question for this list . My tweed setting has a large volume drop. I have read others have this problem but haven;t seen a fix for it. Any ideas?
I will checking IC voltages to make sure power leads are getting it there.

-matt

[Pierre]

hi !!
so far i have builded tree GT2, and all of them have the same problem...What i do is set the gain at 50% max and use a TS 808 (a clone) or another overdrive to push it...
Another usefull thing is to put a non true bypass stompbox in the front to reduce that nasty feedback noise...

[chemman]

I will sheild some more wires and see if I can minimize it but prob not. Any ideas on the low volume for the tweed setting. I have read that someone had a similiar problem on build reports on tonepad.com but the fix is not clear.

Thanks for helping me get this awesome pedal optimized.

-MAtt

[plucky]

Hi all,

All your squeal problems are solved if you change your IC for new ones... That's the trick... 

Regards

[fxdfxd]

Hi all,

All your squeal problems are solved if you change your IC for new ones... That's the trick... 

Regards

I tried many different ones, and there is alays the same problem :|

-fx

[Gringo]

Liberal use of shielded wire, and a short, neat wiring did the trick for me. I also had to wire the bypass switch to ground the input when the fx is bypassed to avoid squealing in bypass mode.