Roadster head high pitch hum

[Gonzo420West]

Hey everyone i just bought a used roadster head and when i switch between channels 1 or 2 to 3 or 4 it will start to hum. It stops with a quick flip of the standby switch or sometimes when you strum the guitar (although playing sometimes doesnt stop it). Also when i turn the volume up just above bedroom level it start to have like this fuzz or hiss that comes and goes as well even when you hold a note. Im assuming this isnt normal could i maybe have some bad tubes?

 

[KH Guitar Freak]

Hey everyone i just bought a used roadster head and when i switch between channels 1 or 2 to 3 or 4 it will start to hum. It stops with a quick flip of the standby switch or sometimes when you strum the guitar (although playing sometimes doesnt stop it). Also when i turn the volume up just above bedroom level it start to have like this fuzz or hiss that comes and goes as well even when you hold a note. Im assuming this isnt normal could i maybe have some bad tubes?

Have you checked the guitar cable and the guitar jack connection???

 

[Boogiebabies]

Preamp tube or blown filter cap. Most likely preamp tube.

 

[Gonzo420West]

yeah cables and connection are good. Upon playing with it more its actually in the ch 3/4 any any voicing (raw, vint., modern) and happens about 80% of the time but only while in spongy mode. If i flip it to bold it stops then back to spongy it happens again. Could this be a problem with the variac circuit or are you still thinking tubes. Im not to knowledable aboutt ube amps as this is my first

 

[Gonzo420West]

Check out this vid

http://www.youtube.com/watch?v=7HdouAwwJV4