F-50 feedback on channel two

[mikeyp]

My f-50 will feedback very easily. It'll do it with the gain anywhere from 10 o'clock or higher, no contour. All I have to do is let go of the strings and it'll do it. I plugged a buddies guitar in last night and it still did it. Could this be a tube issue? How about playing environment, like lights or room size?

 

[plumptone]

Hollow-body guitar or solid body?

Try running straight into the amp - no effects, nothing in the loop, reverb off.

Also, definitely check the preamp tubes. One by one replace with a known good one. It's probably not V4, but run through all the others to try and isolate the cuplprit.

It's not likely an effect of the room size or playing environment - although if you're standing right next to the amp (like REAL close), that could have something to do with it. To test - move back, or to the side.

 

[Platypus]

Might have some microphonic preamp tubes.

 

[mikeyp]

Its a solid body guitar. I did try going straight into the amp with no effects and it still did it. I didnt turn the reverb off though. I did switch v1 and v2 with v3 and v4 last night too. No go. I have some newer pre's so I guess I could give that a shot.

 

[bgroup]

Same problem here. Did you ever solve it? To further confuse the issue, I only get the feedback when using the speaker in the combo. If I unplug the speaker in the combo and run into a cab, no feedback. That would rule out microphonic tubes wouldn't it? Some sort of weird speaker problem perhaps?

Thanks in advance for any insight. Brent

 

[mikeyp]

Not really. Though mine will do it with a cab also. I lowered my pups a little, which helped mildly. I also bought a 5751 pre amp tube but have'nt tried it yet. I dont use alot of gain so I'm dealing with it.

 

[mikeyp]

Why has my post # stayed the same. I'm stuck at 42. :? Never mind they all change together I see.