F2B Noise

[dela217]

I noticed that my F2B is making noise that I don't care for.  It may be that I just noticed it, but it seems like it just started doing it.  The noise it makes is a slight 60 cycle hum.  It does it with no instruments plugged into it, and it does it as soon as it is turned on.  So, I guess it has nothing to do with the tubes because the tubes aren't even warm yet.  The noise does not get any louder when the F2B is turned up, and the noise is also there when the volume is off.  It is not the power amp, because I isolated that from the F2B and no problems there. The noise is in both channels too.  Any ideas?  Simple fix?  Send it back to Alembic?
 
Michael
 
(Message edited by dela217 on December 13, 2007)

[mica]

The filter caps probably need work. Check and see if the insulating foam has deteriorated. Sometimes you can resolder the leads that have wiggled free, depending on how close to the can they broke away. Worst case is you need new caps (and new foam too!).
 
There are other causes, but the filter caps are the most likely.

[lbpesq]

Michael:
 
My F2B had a similar problem, only intermittent.  If you banged it on top, the hum would go away for a while, but not long.  My amp guy replaced the caps and foam (which had deteriorated) and it now works fine.
 
Bill, tgo

[dela217]

Thanks everybody!  I will order and replace those pesky caps.
 
I got no foam either.