Tech 21 VT Bass Background noise because of 4013?

[Luqqas]

Hi there everybody,

My issue is next:

VT Bass (Tech 21) when is bypassed (and also when the effect is on) produces a background noise, irregular. Like bubbles sometimes. It's not hum or hiss noise. If a high gain signal is added, becomes more noisy

Is it possible that the 4013 switching method is in malfunction?
Could this IC be damage, introducing noise?

Regards!

[Luqqas]

For the record, I tried with diferent power sources: 9V Batery, switching power source and good, clean and homemada power supply. All quality stuff. And nothing, same issue. 

[R O Tiree]

Electrolytic caps that are nearing the end of their useful life can make sounds similar to those you are hearing. It might be time to try replacing them?

[Luqqas]

I'll give a try to Electrolytics caps and replace it. Although the unity is not old. I mean, Character series is fairly new, don't?

[R O Tiree]

It could be a loose connection in the lead to the guitar? Or maybe the power supply?

[Luqqas]

Here is the schem for 4013 section



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