Sunking V3 Oscilate!

[J. Ignacio]

 Hi guys! I was trying to add more bass in Klon and now it oscilates when the gain pot is full or 3/4 (using vol and treble at 1/2) when I don't play guitar.
I changed various cap value and R19 (15k to 3,3k)

Cap change:

C1, IN cap (100n to 220n)
C4 (68n to 100n)
C5 (68n to 100n)
C14 (3n9 to 6n8)
C13 (820pf to 1n)
C22, OUT cap (1uf to 4,7uf)

R19 (15k to 3,3k)

I use 1n270 diodes and MAX1044 IC with TL082. I made it true by pass.

Well, I hope you can help me. Pedal bass are better now but I think it needs a little more and I want to eliminate the oscilation.

Thanks for reading.



Bye!

[madbean]

The cap value changes should not cause any oscillation, but possibly the resistor value change did. Put it back up to 15k to see if that eliminates the problem. Instead, increase C7 from 82n to 330n.

[J. Ignacio]

The cap value changes should not cause any oscillation, but possibly the resistor value change did. Put it back up to 15k to see if that eliminates the problem. Instead, increase C7 from 82n to 330n.

Thanks for answer. Yes, I change again the resistor and it's the same.

C7 is for clean dirt? i will try this to increase bass.

[madbean]

Increasing C7 changes the corner frequency that the clipping in the overdrive section operates on. The stock value of 82n gives you about 128Hz. Increasing the cap to 330n pushes it down to 33Hz which is more suitable to bass.

Also, you should consider increasing the value of the tone cap, C14. I would try 10n. This will actually help prevent the oscillation as well as move the tone control range down. But, you might want to check over your soldering as well...make sure you do not have any solder bridges anywhere...this could also cause the oscillation problem.