F2B Noise Log Out | Topics | Search
Moderators | Register | Edit Profile

Alembic Club » Owning an Alembic » Troubleshooting » Archive through February 01, 2008 » F2B Noise « Previous Next »

Author Message
dela217
Senior Member
Username: dela217

Post Number: 852
Registered: 6-2002
Posted on Thursday, December 13, 2007 - 11:04 am:   Edit Post

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
Moderator
Username: mica

Post Number: 4973
Registered: 6-2000
Posted on Thursday, December 13, 2007 - 12:32 pm:   Edit Post

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
Senior Member
Username: lbpesq

Post Number: 2761
Registered: 7-2004
Posted on Thursday, December 13, 2007 - 12:37 pm:   Edit Post

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
Senior Member
Username: dela217

Post Number: 853
Registered: 6-2002
Posted on Thursday, December 13, 2007 - 1:18 pm:   Edit Post

Thanks everybody! I will order and replace those pesky caps.

I got no foam either.

Topics | Last Day | Last Week | Tree View | Search | Help/Instructions | Program Credits Administration