My amp smells like fire!

[alex1fly]

I've read through the manual and I think I know what the problem is, but I'd like to see what you guys think about it.

I was using my Roadster at practice last night in a college house that is not electrically grounded (but no rain or anything). After a minute or so of being on it popped and shut off. The fuse was blown and there was a funky burning smell. Got some more fuses, blew two more and decided to call it a night; this time however, the amp made a really loud noise while in the "On" position (not in Standby) before it turned off again. Read in the manual, checked out my power tubes, found that one of tubes did indeed smell like burnt material and its particular socket had black residue on it. The tube in question was on the far right, farthest from the Input jack. Does this sound like a simple power tube short? Is it okay to put my stock tubes back in and test it with the residue on the one tube socket?

I should add that I'm using EL-34s and for about the first 30 minutes of their use I hadn't set the Bias setting to EL-34, but I did that and used for a couple of weeks before this happened. And last week the amp was making some softer crackly noises that I just attributed to a bad cable. Thanks a bunch!

Alex

 

[WhoFan]

Re: My amp smells like fire!

if it was me i'd take it to a tech... fuses blow for a reason.... inside there could be further damage...

 

[J Moose]

Re: My amp smells like fire!

The fuse was blown and there was a funky burning smell. Got some more fuses, blew two more and decided to call it a night; this time however, the amp made a really loud noise while in the "On" position (not in Standby) before it turned off again. Read in the manual, checked out my power tubes, found that one of tubes did indeed smell like burnt material and its particular socket had black residue on it.

I should add that I'm using EL-34s and for about the first 30 minutes of their use I hadn't set the Bias setting to EL-34, but I did that and used for a couple of weeks before this happened. And last week the amp was making some softer crackly noises that I just attributed to a bad cable. Thanks a bunch!

Bad, bad move there on the bias settings...

Really bad.

Ignoring the crackly noises & popping more fuses...

You blew up your amp.

Take it to a tech or three & find out exactly what happened and what it will cost to fix. Getting a well qualified second or third opinion in this case would be your best move.

DO NOT use it anymore.

Don't even attempt to think for a second that new/old tubes will solve it, because it won't.

The black residue on the socket means that you not only fried the tube & socket (it's probably bunk now) but several other componets as well.

Hopefully not the power & output tran$former$...

Sorry to hear that man.

For the time being it's dead...

 

[missionamps]

Re: My amp smells like fire!

I think there is a good chance you had a power tube failure which then created a flash-over from lug 3 to 2 on the socket.
This is not an uncommon problem with incorrectly biased power tubes. Especially EL34s and bakelite or micanol sockets.
You simply can not just pop any old, or new set of power tubes into an amp and expect decent-good service 100% of the time... most of the time you'll be lucky to survive a few hours of continuous use.
Pull the power tubes and look carefully at the octal sockets them came out of and note if there is an carbon scoring.
If so, you might be able to clean some or most off, (even if grinding some of the socket material out is needeed)... and be OK but, it has been my experience that this problem will keep happening over the next months or years until the socket is replaced.
Most likely one or both tubes are blown up now and you will need to replace those in any respect.
But this time, have the power tube's idle current set correctly.
just added...
or learn how to do this yourself as it is really fairly easy to do with a few tech tools like a Compu-bias http://www.compu-bias.com/
or any other biasing gadget.

 

[Lewguitar]

Re: My amp smells like fire!

Bruce: go over to the Tips and Clips page and check out your playing on We Are Through.

Lew

 

[Farkus]

Re: My amp smells like fire!

Bruce: go over to the Tips and Clips page and check out your playing on We Are Through.

Lew

Y'all got some skills Lew. I'm really impressed by your playing. Very tasty!

 

[alex1fly]

Re: My amp smells like fire!

I think there is a good chance you had a power tube failure which then created a flash-over from lug 3 to 2 on the socket.
This is not an uncommon problem with incorrectly biased power tubes. Especially EL34s and bakelite or micanol sockets.
You simply can not just pop any old, or new set of power tubes into an amp and expect decent-good service 100% of the time... most of the time you'll be lucky to survive a few hours of continuous use.
Pull the power tubes and look carefully at the octal sockets them came out of and note if there is an carbon scoring.
If so, you might be able to clean some or most off, (even if grinding some of the socket material out is needeed)... and be OK but, it has been my experience that this problem will keep happening over the next months or years until the socket is replaced.
Most likely one or both tubes are blown up now and you will need to replace those in any respect.
But this time, have the power tube's idle current set correctly.
just added...
or learn how to do this yourself as it is really fairly easy to do with a few tech tools like a Compu-bias http://www.compu-bias.com/
or any other biasing gadget.

Thanks everyone, I shopped around and found a Mesa repair tech who looked at it the day I took it in (instead of the 2-3 weeks the other techs wanted to take), and even though I had to drive 60 miles (and 60 back) it was definitely better than further frying it. He said its probably the socket and maybe a resistor.