Vox AC15HW Deep Hum On Both Channels

[burtonfan]

Perhaps someone can help me with a problem I created myself. I was playing through my Vox AC15HW yesterday, when I noticed the volume and EQ knobs had that scratchy crackle noise we all hate. As I have done many times before, I pulled the back off the amp, grabbed my can of electrical contact cleaner spray and did the usual routine. Ironically, I had "cleaned" my noisy Fender Blues Deluxe the day before with the desired results.

This time, as plugged in the amp, an awful (and loud) low hum came from both channels of the amp. I turned it off, then back on... no hum. I strummed a few chords and boom, there it was again. I double checked my tubes to insure the were properly well seated... check. I let it sit overnight thinking it may be some unevaporated contact spray. Still hummin' this morning.

I realized I cause this myself with a spray can, so it must be something simple. Any suggestions are welcome.

Thanks!

 

[CirrusBand]

The scratchy pots. Did they just suddenly start scratching? Were they fine the day before? If so, could be a failing component and not your fault really that it got worse after you went poking around with the contact cleaner...

 

[moonlighter]

Does it sound like open ground hum? I would check your input jacks and clean the contacts with a file. How in depth was this pot cleaning? Knobs removed and nuts loosened? I haven't been in one of these HWs before, but if the pots are just grounded on the chassis without any bus wire any one of them being loose can create an open ground.

 

[gusfinley]

Noisy pots could be due to coupling caps that are leaking DC. Do you have a meter to read the DC voltages across the outer lugs of your pots?

 

[burtonfan]

Thanks for the input folks. I tried some of your suggestions. Long story short, it was a bad V1.

Problem solved!