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Having an issue with the Ratt DLX in a combo build I am doing. I have used the Ratt DLX pcbs before with no issue but now when the filter knob is turned up a tone is generated that leads to feedback and harsh noise. I have verified that everything is grounded, swapped ICs, and verified components within my abilities. Issues persist inside and outside of the box/other pcbs.
Any Ideas on what could be causing this? Images below.
You’re correct, that shouldn’t be happening.
I strongly recommend doing a full re-flow, especially on the clipping diodes. Take your time, and have extra solder ready in case you need it. Be prepared to remove any excess solder as well. Keep the tip clean and tinned throughout the process.
Also, be cautious with the wires, as a few strands are showing. You may need to redo them if necessary. Make sure to route your power wires away from the audio path wiring as much as possible.
Following up here. Replaced the diodes and re-flowed every joint.
Circuit is still generating tone when enabled. When I pop the opamp out the noise stops (i’ve tried multiple op amps) which leads me to believe the problem is in the gain stage. I’ll keep working on this and follow up when I have more updates.This is the exact kind of scenario where an Audio Probe will help you discover the problem area.
All I can do from my end is visually inspect your project which usually works, but not always.
Dug into this with an audio probe over the weekend and believe I solved my problem. The gain pot was a little funky so I replaced it then was able to fine tune the Ruetz mod where I think some of my high end frustrations were coming from.
I started by going for the same configuration i had on my last couple builds (1K trimmer, 100ohm in R7) but found myself preferring the 100ohm trimmer with a jumper across R7 this time.
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