smoke from amp...what happened?

[esandes]

while jamming smoke started coming from the amp (marshall 1987). i shut it down and started it up again after 5 minutes and it was fine. i continued to jam.

when i got home i opened it up and all of the guts looked fine, visually. the amp sounds good still. i haven't replaced the tubes.

my theory is the bias was adjusted hot with the previous tubes. i popped in some groove tubes "7" power (high power) tubes and the smoke incident happened after that. previous jams with the groove tubes were fine.

what could it have been?

 

[Myaccount876]

Re: smoke from amp...what happened?

Have you checked the fuse? It didn't blow if it started working again, but something may be fishy around there.

 

[uOpt]

Re: smoke from amp...what happened?

Could also be an insect that got burned up or something along those lines.

 

[esandes]

Re: smoke from amp...what happened?

yeah i was thinking it may have been cobwebs or spiderwebs maybe. the smoke wasn't billowing out or anything. it happened at the start of this spring.

 

[crusty philtrum]

Re: smoke from amp...what happened?

The tone magic is in the smoke, and that's why it's always best to keep the smoke safely inside the amp.

 

[Chickenwings]

Re: smoke from amp...what happened?

do any of the tubes redplate when you play now?
A puff of smoke usually means a burned resistor so id be looking inside again much more closely.

 

[esandes]

Re: smoke from amp...what happened?

do any of the tubes redplate when you play now?
A puff of smoke usually means a burned resistor so id be looking inside again much more closely.

i'll look again. but i recall the power tubes had their normal orange glow. all of the resistors look new. if one cooked would it be easy to spot.

 

[GuitarStv]

Re: smoke from amp...what happened?

The tone magic is in the smoke, and that's why it's always best to keep the smoke safely inside the amp.

It's also why letting the magic smoke out of electrical components usually means they stop working.