Warranty is 12 mths. Return it to the store you bought it from to get it checked out/repaired.

i had this happen with a valvetronics amp. sent it out there were cracks and bad solder joints on the pcb board theres one in those amps. when the amp got hot the cracks opened. broke the circut. i had the tech re solder the bad joints and he put solder tape jumpers over the cracks . cured the problem.

sich,
Yep I got it fixed, I took it to a tech here in central FL he told me that the problem was the FX loop jacks and switch were dirty... I know , I know sound like BS but the amp works better then ever.
I did notice after I got it back that the fx bypass switch works differently then it did before.
Before the repair the switch had to be in the "ON" position with nothing plugged into the fx jacks or there would be no sound.
After the repair the bypass switch was returned in the "OFF" position and if I switch it "ON" the sound only gets slightly muffled.
I hope this make sense.
SO I guess my amp always had this problem from the beginning and just got worse as the switch got dirtier, at any rate it works and I went out and bought a can of DEXOIT D5 as part of my VOX survival kit.
good luck

Voxman or any other Vox folks out there, can i get some advice please?
I'm new to the forum but I think may had a similar problem on my AC50CP2...

I was at practice last week and the volume suddenly dropped. The amp was not entirely silent, I could hear my guitar... but only just. There sound was not distorted - it was my normal guitar sound just very very quiet. Same on both channels. The problem persisted for about 5mins. I checked my cabling and after some un-plugging and plugging back in, the volume came back (immediate, no fade). I put it down to a dodgy cable somewhere.
A few days ago I was back at practice when, after about an hour of playing I had the same problem. After 10mins or so of checking with cables I figured out that there was something amiss with the amp.

I've been playing today for several hours with the FX loop unplugged and just a guitar straight into the input and I've had no repeat of the problem.

I was worried that this might be something complicated like a transformer/rectifier problem, but I'm mystified why that would be an intermittent fault. I was all set to change out the valves to see if that would fix it, but I'm reluctant to do anything unless I can get it to go wrong again! Besides, the amp is barely 18months old and had been well looked after, despite quite a lot of use and gigging - I wouldn't have thought the valves would be on the way out?

After reading the post by fuzzydog, I wondered if this might be dirty connectors in the FX loop. But it seems unlikely to me - I'd have expected the volume to cut completely?

Any ideas what this could be?

Grateful for any help,
Alex

Thanks for the quick response! I got in there with some cleaner and a cotton bud this evening and was quite surprised at the amount of gunk that came out.... I share your feeling on the quality issue, Fuzzydog - for amps in this price range I'm very surprised that we're talking about corrosion of jack contacts! Surely a better quality material could have been used?!
Been playing all evening and no repeat of the problem so far. I'm back in the studio on Wednesday and I'll plug into the FX loop, then we'll see if the problem returns or not!
Cheers

Glad you guys have got your problems sorted. With volume/tone/crackling issues It's always best to start with the easy suspects first, so regardless of which amp you have I'd always recommend giving ALL the jack sockets a good cleaning with electrical switch cleaner (& you may need a few!).

Even on brand new amps, cleaning the sockets can still resolve problems like this & I think the oxodisation issue has a lot to do with how long the amp has been in storage prior to sale, and of course the storage conditions (temperature, hunidity etc).

I honestly don't know why Vox gear seems to be prone to this oxidisation issue, as in all my years of playing I've never had any similar problem with any other amp manufacturer.
I have flagged the quality of jack sockets to Vox over the years (it's a very common issue with the Valvetronix line) and have suggested it might solve/prevent a lot of issues if these could be upgraded across its product range. Whilst I appreciate that there may need to be a cost adjustment for this (I know that there's very tight budgeting consideration by Vox, here), I can't think any extra cost (especially at trade prices) would be terribly dramatic & I'm sure folk would be more than happy to pay a few dollars/pounds more to have a socket upgrade.

Rich