If a component is microphonic, you can bet your bottom dollar that it is affecting the sonics.
In terms of what is causing this, it could be tube based or something as simple yet complex as an intermittent solder connection. Short of pulling and reseating all of the ( Known good ) tubes and re-flowing all of the existing solder joints, it may be next to impossible to find.
Just think about this though. If you think that it is frustrating, this is the kind of stuff i make my living doing. Needless to say, i have to hide the hammer from myself with some units : ) Sean
In terms of what is causing this, it could be tube based or something as simple yet complex as an intermittent solder connection. Short of pulling and reseating all of the ( Known good ) tubes and re-flowing all of the existing solder joints, it may be next to impossible to find.
Just think about this though. If you think that it is frustrating, this is the kind of stuff i make my living doing. Needless to say, i have to hide the hammer from myself with some units : ) Sean