Amp troubles

E-rock · 05-17-2011, 07:49 PM

Here it is:

You can see that one of the wires is touching the bracket of one of the tubes.

THe silver part i was referring cant be seen unless you pull the wire back...right there, it is actually touching

**thesteve** · 05-17-2011, 08:04 PM

Hmm...that's definitely not good. I would either just bend the thing with some pliers, or dismount the speaker and rotate it so that isn't happening anymore. The former option would be the easier.

I wonder if having the exposed wire touching the bracket could cause the signal to short out right there, thus you have no signal going to the amp.

E-rock · 05-17-2011, 08:06 PM

hmm.. ok. let me see here... I will do one of those two things and then try it again.

Major Tom · 05-17-2011, 08:49 PM

You have to find a way to keep that wire off the tube retainer - staple it or whatever to the cabinet around the other direction, perhaps encase it in some silicone tubing (withstands high temps without melting). If it were me, I might re-route it and then just wrap some electrical tape around the bare spot, making sure that it would not be able to touch anything metal even if the tape fell off, instead of replacing the wire. Anyway, you do not want the bare conductor of the speaker wire (at least the one that isn't connected to ground) to make electrical contact with that retainer, which is metal and, I assume connected physically to ground - that would short out your output. It is possible that bare spot of the wire did short out, and might have taken out some component in the power tube circuitry, possibly even the output transformer.... Check and see if there are any fuses inside the chassis. Many amps have multiple fuses to protect various circuits.

Yes, that is a SERIOUS design / manufacturing flaw. Built in self destruct. I hope it has some venting for the heat - a closed back on a tube amp...?!

Under warranty? They should cover that.

E-rock · 05-17-2011, 08:53 PM

OK i bent the stem... its still right between the two tubes.. But at least its not touching. And still no sound, however. =(

And its not REALLY a closed back... it has a grill on the back of it, with thousands of holes in it. I just had to unscrew it to be able to touch anything, but it is essentially an open back.

Major Tom · 05-17-2011, 09:07 PM

You could try swapping out tubes, but.. One of the 2 conductors of the speaker cable is connected to ground, the other is not - if that is the one whose bare conductor touched the retainer... My guess is that something in the amp is blown because of that. In general, electronic circuits fail when the output side of the circuit is a dead short. It is possible the output has a fuse, and that blew. Otherwise, I'd be looking into the warranty thing. Even if it is out of warranty, they may cover it after looking at that picture.

**thesteve** · 05-17-2011, 09:11 PM

Quote:

Originally Posted by Major Tom

You could try swapping out tubes, but.. One of the 2 conductors of the speaker cable is connected to ground, the other is not - if that is the one whose bare conductor touched the retainer... My guess is that something in the amp is blown because of that. In general, electronic circuits fail when the output side of the circuit is a dead short. It is possible the output has a fuse, and that blew. Otherwise, I'd be looking into the warranty thing. Even if it is out of warranty, they may cover it after looking at that picture.

In the manual for this amp, one of the solutions given the symptoms is internal power tube fuse is blown.

E-rock · 05-17-2011, 09:19 PM

i read that too, I just didn't know if the fuse could be blown and the tubes still glow.. Oh well. Sounds like no matter what the case is, It is now offiically above my skill level to handle. So disappointing!!