Hi, just tried out my new SV20H head for the first time, running it through my fender 4 x 12 cab (8 ohms). Sounds awesome but I noticed a slight hum when the effects loop is activated. I was running a solid gold FX surf rider through the loop but it did the same with a Boss Space Echo as well. I also took the pedals out of the equation and just connected both send and return with a single jack cable and it still happened. It isn't a loud hum at all but I'm just checking if this is normal? My Origin 50 head that I have been using for the past year didn't make any hum at all with the same pedals!
Hello Paul,
We would recommend contacting the dealer you purchased the SV20 through so they can arrange for the amplifier to be looked at on your behalf.
Kind Regards
Marshall Support