proco rat vero clone noise issues with gain past 12 o clock

[snow123]

I built a vero proco rat using the layout below, and for some reason i get a high pitched squeal when i turn the gain up past halfway, and i also get some weird tone suck with that, and turning the filter knob down increases the volume of the squeal.



And here's the insides of the pedal:








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also, im using a 33pf cap instead of the 30pf, and im using a 2n5457 instead of the 2n5458.

[GGBB]

Sounds like feedback oscillation - try keeping the input and output wires well away from each other and from the circuit. A shielded input wire might also help.

[idy]

The "filter" control on a Rat works "backwards" of a normal tone. CW=less treble, CCW=more. So when you turn it "down" you are cutting less treble and any feedback issue will be worse.

This is not good pedal for spaghetti wiring with in and out all twisty. You may even want to try it first without a stomp switch just to confirm it is working, *always* a good idea.

[snow123]

The "filter" control on a Rat works "backwards" of a normal tone. CW=less treble, CCW=more. So when you turn it "down" you are cutting less treble and any feedback issue will be worse.

This is not good pedal for spaghetti wiring with in and out all twisty. You may even want to try it first without a stomp switch just to confirm it is working, *always* a good idea.

well everything else works as it should tho

[aron]

It's usually input and output wires too close together along with too much gain. I've used shielded cable and it seems to help a lot.

[snow123]

im gonna replace the output wire since its just 2 wires soldered and heatshrinked together.

[snow123]

im gonna replace the output wire since its just 2 wires soldered and heatshrinked together.

just replaced it and nothings changed.

[aron]

Try shielded cable on the input. Ground the shield.

[snow123]

Try shielded cable on the input. Ground the shield.

like this? https://www.amazon.com/Gavitt-Braided-Cloth-Covered-Pre-Tinned-Pushback/dp/B00OJN9IM0/ref=sr_1_9?dchild=1&keywords=shielded+wire&qid=1628657109&sr=8-9

[antonis]

Any bulk patch guitar cable will do the job..

Additionally, you may raise 100pF cap up to 150pF..

[mdcmdcmdc]

That oscillation issue in Rats is pretty common. Some people have luck by increasing the 30pF to 100pF or larger (that's never actually worked for me), but the only thing that's ever solved the issue in my experience is a buffer in front of the pedal. If you have a boss pedal kicking around, stick it in front of the rat clone in your chain and see if the oscillation stops.

[mdcmdcmdc]

There's a good chance that whatever the core issue happens to be is being exacerbated by dint of this being a vero layout, with signal crisscrossing around and everything kind of out in the open rather than a nice and tidy PCB. That said, I have about 3 or 4 proco rats sitting in a box waiting for me to get around to "fixing" them that all do this. I'm not sure if there's actually a means to troubleshoot other than replacing every cap and the IC.

It may also have something to do with the mains/wiring in your house, as I have at least one wonky one that will self oscillate at my apartment but not at my practice space.

[duck_arse]

hey! are we getting the band back together?

[Phend]

i get a high pitched squeal

R U running this thru a Pignoze amp ?

[snow123]

Any bulk patch guitar cable will do the job..

Additionally, you may raise 100pF cap up to 150pF..

so push back cloth wire should be fine?

[snow123]

i get a high pitched squeal

R U running this thru a Pignoze amp ?

nope an orange micro dark lol

[mdcmdcmdc]

Are you using an LM308 and have you tried swapping out a different IC? Looks like you socketed it.

[r080]

That wire should be fine, as long as you ground the shield.

I think the point was you can use whatever you have, even just the cable from a cheap patch cable.

[snow123]

Are you using an LM308 and have you tried swapping out a different IC? Looks like you socketed it.

yes, I'm using an lm308, and i tried swapping it for a ua741 and tl071 and nothings changed.

[kaycee]

hey! are we getting the band back together?

Only 15 pages to go till resolution.

I'm convinced this is RG having a larf