RoadKing making LOUD HUMM when effects loop is engaged.....

[RoadKinger483]

Hey guys I was practicing this afternoon and I decided to engage the effects loop but, when I did a REALLY LOUD HUMMING noise came out through the speakers. I switched it off and then on again and the same thing happened. Could this be a faulty preamp tube? V4 or V5 maybe???

 

[tele_jas]

It could be a preamp tube or one of the cables to the FX unit.... or it could have been the FX unit.

What did you have in the loop?

One way to test the loop alone is to run a cable from the send to the return and then engage the loop and see if it hums, if it doesn't hum, then it's not the FX loop. If it does hum, try using a different cable.. if it still hums, try swapping the tube.

Some fx units and stomp boxes can have a bad hum due to the power supply not being properly sheilded or using bad cables to the unit.

Hope this helps.

 

[RoadKinger483]

thanks tele_jas. I probably should have mentioned that I didn't have anything connected to the loop yet. I just engaged it. So, I guess i'll try swapping out the tube.