Vox AC30CC2 problem, lots of hiss and random noises
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Posted on Oct 10, 2010 03:47 pm
Marius
Member Since: Jan 17, 2010
Hi, I have a AC30CC2 and lately it's just gone crazy. It makes weird noises but mainly a lot of hiss and noise that shouldn't be there. I figured that when my computer charger is in the same outlet it makes even more noise but taking everything out of the outlets except for the amp it's still a lot of noise. Could this mean bad tubes? If so what kinda tubes am I gonna get? Thanks.
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MariusMember
Since: Jan 17, 2010
Oct 10, 2010 04:08 pm to add a little something, I do not understand how having anything else in the outlet could have anything to say (the pc charger doesn't even have earth), and my mixer was plugged in and the amp sounded like a washingmachine. and when I pluged in my usb interface from the mixer to the computer suddenly the noise was reduced, weirdest thing ever.
Oct 10, 2010 06:06 pm On your AC30, it could have a bad tube. One thing to try is tapping on top of the amp, and listening to the amp. See if you can hear the tapping coming out of the speaker.
The thing is, that it could be a number of different tubes in the amp. If your not acquainted with tube amps, take it to someone, and have them look it over.
The other thing that your encountering in the audio chain, is random noise from your computer screen. LEDs are noisy! And even though your computer doesn't have a ground wire doesn't matter. Remember, that a neutral is the ground from your power company. So, it is still possible to get ground looping without a ground wire.
MariusMember
Since: Jan 17, 2010
Oct 11, 2010 02:00 pm well, I've never opened any tube amp before but I am an electrician so I'm not totally lost with this stuff. Fixing the tubes of the amp would certainly solve my amp problem but I would still have the problem that I cannot use my computer and/or mixer at the same time. what's weird is that it was never like this before. Any solutions to that problem? I will try to tap the top though, would it be bad to tap the preamp tubes?
MariusMember
Since: Jan 17, 2010
Oct 11, 2010 02:00 pm well, I've never opened any tube amp before but I am an electrician so I'm not totally lost with this stuff. Fixing the tubes of the amp would certainly solve my amp problem but I would still have the problem that I cannot use my computer and/or mixer at the same time. what's weird is that it was never like this before. Any solutions to that problem? I will try to tap the top though, would it be bad to tap the preamp tubes?
Oct 12, 2010 12:40 am Tapping the top and listening for any transients will just give a location to start with. An output tube can also be microphonic.
As for your computer and mixer, try lifting the ground on the cable. That should do it.
MariusMember
Since: Jan 17, 2010
Oct 13, 2010 02:07 pm I tried tapping it and shaking it a little but noticed nothing at all. And by lifting the ground do you mean take away the ground on the power cable of the mixer or the outlet? The computer does not have ground though.
Oct 13, 2010 08:27 pm Well, it could still be a tube. Just sometimes you get lucky, and they go microphonic first.
For the ground lift, I was referring to the signal cable. Lift the ground off of the 1/4" or XLR.
