Help required dammit!

Quattroste

:mad:

I had to move some furniture around in the house today and had to move my amp too. Did all the moving around, room looks well, I'll sit down and play some guitar. No Sound! I only got the amp on Tuesday.

Anyhow, the amp switches on but absolutely no sound. I had a look through the metal grill on the back and one of the tubes seems to be glowing blue at the bottom. There are 2 power tubes that are switchable, an EL84 and a 6V6. I'm not sure which one is the one that is blue but they are both constantly on.

If there is one blown tube would this stop the amp from working even when switched to the other tube? Does a blown Power tube mean no sound?

This has p1ssed me off

darrenw5094

What amp have you got? I am interested to know what amp has 2 different types of power valve that are switchable.

Voodu Child

Hard luck man, that would suck to have a problem on such a new amp. Hopefully its something very minor.

I would ring Matamp, from what I hear you'll get in touch with the guys that designed the amp straight away. They can hopefully talk you through it and troubleshoot the problem.

The have an 'outside hours' number on the website, so you might even get in touch with them tomorrow.

-=al=-

could be the output transformer, happened to me once and tubes looked blue wen it happened although i heard a little trickle of sound but yeah i dunooo really, just thwoing it out there

Quattroste

Darren it's a Matamp First Lady.

Yeah I'll give Matamp a shout tomorrow. They're a sound bunch of lads so hopefully they can help me out. I just hope I don't have to send it back to them.

Al, there was the tiniest sound coming from it.

Anyone know what would cause the output transformer to fail?

-=al=-

a tube blowing or anything overloading it... if the tubes were old or whatever they can do that, some amps have a fail safe that prevent the tubes that are having trouble from reaching the output transformer, but sometims they can take it out with it too

boycey

Sorry to hear that Quattroste, t'is dissapointing. Im sure the Matamp lads will be very helpful, the Matamp forum lads are a knowledeable bunch too. Anyways hope its sorted for you soon.

Eoin Madsen

Quattroste wrote: »

:mad:

I had to move some furniture around in the house today and had to move my amp too. Did all the moving around, room looks well, I'll sit down and play some guitar. No Sound! I only got the amp on Tuesday.

Anyhow, the amp switches on but absolutely no sound. I had a look through the metal grill on the back and one of the tubes seems to be glowing blue at the bottom. There are 2 power tubes that are switchable, an EL84 and a 6V6. I'm not sure which one is the one that is blue but they are both constantly on.

If there is one blown tube would this stop the amp from working even when switched to the other tube? Does a blown Power tube mean no sound?

This has p1ssed me off

Valves don't really "blow" like light bulbs, that's sort of a misconception that people have. If a valve was damaged, the other power valve in this amp would still work (guessing it's a switchable single ended amp), so the silence is not a valve failure in itself at least. Depending on what's damaged about a valve, it will usually blow a fuse. If the amp has a HT fuse it would effectively be like being in standby - the amp would still power up.

(Just fyi, the filament heaters in both valves have to be lit up all the time so that you can switch on the fly. The plate voltage etc is killed on whichever valve is not in use. Repeatedly switching the filaments on and off at the same time as plate voltage would cause cathode stripping, much like repeatedly powering up an amp out of standby.)

Blue glowing indicates gas inside the valve. It may or may not be a fault depending on severity. It's not uncommon, and while it could eventually degenerate into a valve failure, it doesn't necessarily imply one in itself or explain why the amp is not functioning.

My guess diagnosis :pac: on the basis of your description is that one of the power valves was originally knocked in transit and was already living on the edge. Moving it again caused the problem to exacerbate. When you powered up the amp, the plate voltage shorted, the HT fuse blew, and now neither valve is getting plate voltage.