Tweet
Hi:
I have a Peavey MP4 mixer that initially had a loud hum as you increased the master reverb (Effects Bus).
I tried swapping U4 and U5 but made no difference.
After looking around, the ground on the reverb pan cables appeared to be a large contributor to this type of issue.
As a quick test, I paralleled the ground connections with wire from the RCA connectosr back to the Molex connector.
The hum went down, but now I have a random oscillation (comes and goes with random duration).
All the issues seem to be sitting on the effects bus.
With the master reverb turned all the way down, the amp is quiet and has no oscillation.
Anyone seen this before? Any ideas what could be going on?
I have a Peavey MP4 mixer that initially had a loud hum as you increased the master reverb (Effects Bus).
I tried swapping U4 and U5 but made no difference.
After looking around, the ground on the reverb pan cables appeared to be a large contributor to this type of issue.
As a quick test, I paralleled the ground connections with wire from the RCA connectosr back to the Molex connector.
The hum went down, but now I have a random oscillation (comes and goes with random duration).
All the issues seem to be sitting on the effects bus.
With the master reverb turned all the way down, the amp is quiet and has no oscillation.
Anyone seen this before? Any ideas what could be going on?