Vox AC15 Help

[gloriousfrance]

Hi all, I'm new to the forum and fear that my question will get me cast out of here just as quickly as I joined. I'm not sure where else to turn to so if you can direct me to the right forum that would be appreciated as well. So here it goes: I have a 1 year old Vox AC15C1. The past few days that I've played it, it sounds great and then after about an hour of playing, each note becomes "static-y" or "fuzzy." Then, just minutes later, the volume drops completely. Does this sound like it needs new tubes or something much bigger? I thought I'd check here before I start looking for a repair shop. Thanks!!!

[booj]

Do you play loudly through the amp? vibration can cause a component to work loose from the board. Not to be vague sounding, but that would be my first guess. If you can get it apart check for components that are mounted above the board for ventilation reasons. Make sure the amp has been off for at least 15 min. and is unplugged before you do that. If you see small "halo's around the connection points and the solder like it's cracked in a circle around the component lead, it's a good clue that it's not making good connection.

[Mick Bailey]

Tubes get fairly hot fairly quickly so thermal faults related to the tubes themselves (generally) appear quite soon after switch on. The thermal soak for the rest of the amp takes time and I'm thinking the same as Booj - you may have a joint or component opening up with temperature rise.

You don't say how much experience you have with tube amps - the usual caveats about safety apply. But if you play a hairdryer set to cold over the circuit board while the fault is present you may be able to check if it goes away - sometimes you can get a good idea of where the fault lies to narrow things down a bit.

[pdf64]

Have you checked that it isn't still under a manufacturer's or retailer's warranty?
Pete

[Chuck H]

Do you have active guitar pickups?

[The Dude]

Haven't seen it in the Vox's particularly, but I recall working on an EL84 Crate amp that did this exact thing. It was a defective EL84. A tube swap might be worth a try.