Angry llama squeal issue

[August]

Hi,

I’ve build an angry llama kit, but hear a high pitched squealing noise when the circuit is turned on. Any tips?

 

Things I’ve tried o debug: Reflowed all pcb connections, installed new electrolytic caps (not shown on pic), swapped ic, set bias voltage to 5.5V, battery powered the circuit & audio probed the circuit. Noise is already heard after R2… R3 is removed in the picture and it still shows my first trial with angled caps. This is now done with cleaner new caps (still angled because of component height)

 

Hope someone can help me 🙏

 

 

[Barry]

Make sure the Boost in the middle is not cranked. Not my circuit but it is called Angry for a reason.

If that doesn’t help and you have spare components you could try changing C4 from 100p up to 330p or 470p

[August]

Thanks for the help!

The building doc I used mention guitarpcb on every page so I thought this is the site to call for help 🙂

I’ll try to replace C4. Do the values change tone? I’ve seen pictures of this kit with tantalum caps instead of ceramics at c3 & c4. Would that help? Could be that I fried some components, my soldering technique isn’t perfect.

 

[Barry]

The value prevents noise. Does not affect tone. Do not use tantalum.

When I said not my circuit I meant original design.

[Barry]

Also, just flip the switch and tell me if it goes away.

[Author]

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