Vox problem - ring

My amp JUST got a 'ring'...not a buzz, or hum, or hiss. When I tap on the control plate it seems to make it ring louder, and almost makes it's own tone when i tap it.

To try and clearly describe the issue I'll list the symptoms, and what I have tried and what I have noticed, and what settings I have already tried to troubleshoot.

Things to point out:

-The amp "rings"...not so much a hum, or buzz, or a hiss.
-The 'ring' is similar to the start of a clean guitar feeding back.
-When I tap on the control panel it gets louder.
-Cant tell if I have a bad tube.
-Volume levels pointed out in the video. (it rings regardless)
-Nothing is plugged into the amp.
-The noise occurs regardless of the knob settings.
-I DO have a dimmer in my room, but it has never done this before (3 years)
-The tubes are stock. (maybe 5 years old...not run hard)
-The cut knob does create a mean buzz when turned up.

Category:

Music

Tags:

• vox

[blurpy123]

hey um i was just wondering i have a randall amp and i was wondering if its my squire or amp um i put the pickup selector down and i get a buzz and then wen i move it in between pickups its fine im pretty sure the pickups are just shitty but im not sure do u have any ideas?

[Lukeyourself]

I think a lot of people have that problem. Could be a bad ground wire...more likely its just the wiring in your house. I think my strat does the same thing. If you ever play at a shite venue, you will notice it does it there too. :) Try moving around in your room, or using different outlets. Move away from fluorescent lights and computer monitors.

[lukecyrus]

dude, thats just a bad preamp tube. just tap the preamp tubes individually with a pencil, and you'll that one of them produces the ring. had that problem many times, although the ring on your amp is a little lower than usual...

[Lukeyourself]

Thanks for the tip man! Say, I read on a Brian May web page that he actually pulls 4 of 6 preamp tubes out of his AC30 to make it run cleaner. If I have a bad tube, and just pull that one out (assuming its not from the channel I use) I should be safe right? Or do I need to cap the socket where the tube has been pulled?

[Lukeyourself]

Awesome! It would appear that DID fix my problem! It was one of the preamp tubes for my normal channel, which I use. So I just grabbed the tube from the Brilliant channel (which I dont use) and plugged it in in its place. Left the baddy out. Works like a charm! Maybe I'll make a video of myself doing it! I love youtube. All praise be to her. And thanks Lukecyrus!

[HawkStudio]

Yep...what you have is a microphonic tube....most likely the EF86. Just tap on the tube itself while the amp is running to make sure. Try swapping it out or add some antivibration rings or an isolated mount.

[patfurlan]

I had one of these for Ten Years ... the ring is a bad preamp tube .. the other rule with these guys is to toss the Power tubes every six months .... I changed mine regularly

JJ el 84's are the best current production el84's on the market

[antrorc]

Hi where did you get the flight case? I need one for my ac15c1

[NostalgiaT]

Hey I had a Lose Jack and a brocken Cap on my control board on mine and it would start to ring and like a feedback It was around 40 bucks to have my local tech in Omaha NE fix it. That was after chasing and replacing tubes ect....

[rjmprod]

Total case of monophonic tube/tubes, based on what I heard. feed back hum because of monophonic tube..also would be a good idea to clean or replace the tube sockets, which could be one of the reasons for this type of tube failure.

[2011dtish21]

@blurpy123 The soldering has soe issues, but it isn't that much of a problem

[joelbyrne]

@Lukeyourself You should never pull tubes on a cathode biased amp.

[shawnr26]

Sounds like one of the tubes in the amp is microphonic....which is picking up noises in the amp.

[srv3089]

This sounds just like a microphonic Tube. I had this problem with my krank chadwick. There was a tube in the preamp that was microphonic causing the problem.

[KX36]

Nice clear example of a microphonic valve. So often people talk about microphonics but you don't really know what it is until you've heard it once, then you won't forget.

PS The early AC30 reissues had several problems that later ones had a poor stab at addressing. Most of them relate to the addition of a standby switch which wasn't on the original and isn't necessary; try not to use it, it strains the valve rectifier with surges and shortens its life.