Author Topic: FX-1 has 60 cycle hum -- Ground Loop Problem? (Read 143 times)

stratcat73 · « **on:** February 18, 2008, 06:42:35 PM »

My friend has a FX-1 that has 60 cycle hum until he lifts the ground. He suspects a ground loop problem. Any ideas on how to solve this? Thanks in advance for the help.

Rich

David Houck · « **Reply #1 on:** February 19, 2008, 07:43:29 AM »

Hi Rich; welcome to the board!

60 cycle hum may be related to the capacitors. Check the capacitor leads to make sure they aren't broken or that the solder joints are loose.

olieoliver · « **Reply #2 on:** February 19, 2008, 07:58:12 AM »

I'd start with the simple stuff first. If it's mounted in a rack make sure it's seperated from any other device in the rack.
(i.e. no metal of any other rack items touching another.)
I had this same problem with my Yamaha SPX 90. Upon looking I noticed the rubber feet the were once on the bottom of the SPx90 were missing and allowed it touch the unit below it. I a piece of rubber hose between it and the hum went away.

Olie

freefuzz · « **Reply #3 on:** February 21, 2008, 09:52:17 AM »

60 cycle hum has nothing to do with capacitors, since capacitors come after diodes, which give the capacitors 120hz. you have a ground loop, as olieoliver states. isolate the f1x from anything else in the rack, or cut the shielding off of one side of the sound cable (NOT POWER GROUND), or better, use a behringer (or even better, an ebtech) humdestroyer in between the f1x and the poweramp. this always works.