Amp radiophonic?

[dignlivn]

I have two fender Harvard reverb ll,s
Solid state amps.
Running in poor man's stereo/dual mono
One amp sounds like it gets radiophonic after several minutes of playing .
This just started recently?

Any ideas?
Bob

 

[Frodebro]

Define ‘radiophonic.’ Is it picking up a radio station?

 

[dignlivn]

Yes sir

 

[Frodebro]

The most common cause of this is an unshielded wire someplace early in the circuit that is acting like an antenna.

 

[dignlivn]

Thank you frodebro,
I've heard this with my tube amps, back in the 90,s.
But, not with ss amps?, I'll try New cables.

 

[Frodebro]

Thank you frodebro,
I've heard this with my tube amps, back in the 90,s.
But, not with ss amps?, I'll try New cables.

Tube versus SS doesn’t matter, and chances are that it’s not your cables. An actual wire inside the amp is not shielded (a very short one), and the length of that wire is effectively “tuned” to whatever frequency the amp is picking up. I’ve seen this happen with wah pedals on more than one occasion as well.

 

[dignlivn]

Ok,
Hmm,needle in a Hay stack,thing

 

[Frodebro]

To a degree, yes. But it’s going to be a wire very early in the signal chain because it has to occur before the preamp for you to be hearing it. That narrows it down considerably, as it’s basically happening between the input jack and the first gain stage.