I gather that it is an acoustic hum.
This is the transformer vibrating.Try tightening
the screws or possibly use some rubber gromets to isolate the transformer from
the chassi.
WT
----- Original Message -----From: envia94Sent: Sunday, December 09, 2012 2:39 PMSubject: [xpantastic] Re: Hum interference after recaping my XpanderHi, this is not normal.
You quite likely need a hum eliminator:
http://www.amazon.co.uk/s?ie=UTF8&field-keywords=Ebtech&index=mi&search-type=ss
Cheers,
Tiitu.