[DIY] OT: Tube amp disaster

[Goddard, Duncan]

this same thing exactly happened to a mate of mine- ran a 50w marshall into
the wrong cab-combination and the amp started to smell bad and huff smoke.
he didn't fix it, though, and the same amp sounded better, if a bit quieter,
afterwards. tubes don't seem to like too high a load impedance, though
they'll drive a short until the cows come home. it wasn't the output
transformer though, it was a choke in the ht supply that had burned up a
bit.... excess current.
duncan.

> ----------
> From: 	tomg[SMTP:efm3 at mediaone.net]
> Sent: 	16 August 2000 20:27
> To: 	synth-diy at node12b53.a2000.nl
> Subject: 	Re: [DIY] OT: Tube amp disaster
> 
> I'm no tube amp expert ether but I am a expert on burning tube amps up.
> If it smells like burnt varnish the transformer has gotten hot enough
> to melt the insulation off of the windings. In other words it's shorted.
> The
> good news is the tubes are probably fine. It could be the choke but it's
> doubtful. Does it even have a choke?
> 
> I have fixed a huge pile of toasted amps. At least it wasn't a Marshall
> and Crate has been very good about parts in the past. 
> 
> 
> Tom 
> 
> > After removing the push-pull tubes the transformer should be isolated
> > so that any insulation problem should be detectable.
> > How does the transformer smell? Burned insulation? Burned wiring, or pcb
> > (spark gap).
> > 
> > 
> > m.c. (no tube expert)
> > 
> 
> 


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