Feedback, Oscillation or another name that i don't know in Sansamp GT2 (Tonepad)

[brunoprado]

Hello all, i'm new in this forum and in DIY Effects...

I've just finished the assembly of my Sansamp GT2 from Tonepad and it worked perfect... So I've decided to put in an enclosure (metal) with a true-bypass using a DPDT... After that my problems started! With high gain settings in the amp simulation Marshall and Mesa it has a feedback (microphonic, oscillation) now that is extremelly annoying... I've already tested without the DPDT and it's normal, but as soon as I connect the DPDT the problem is back...

Someone could give me a hint to solve this problem, please?

PS: I'm using IC's TL072CP and TL082CP, transistors BC549... The problem only occurs when the effect is on, not when it's bypassed...


Thanks!

[brunoprado]

Does anyone here made a GT2 Sansamp from tonepad and had a similar trouble??? Or it's just me?

[toneless]

Keep your wiring as sort as possible!

[Connoisseur of Distortion]

try to keep wires carrying different levels away from each other. they might talk enough to make noise.

[brunoprado]

Ok, I'll try something else...

[LP Hovercraft]

Mine did the same thing when I was building it with a DPDT.  I tried a 3PDT switch instead using the outer pins for the bypass switching and the middle pins to connect ground to the LED.  Cured the oscillation problem.  You can get the 3PDT from Small Bear.