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SMOKE JUST CAME FROM MY SVT!

punkrockmike

punkrockmike

Mar 16, 2011
239
3
Minneapolis, MN
www.facebook.com
#1
So i just had my MTI era svt cleaned and given a clean bill of health by a "tech" who was recommended to me by a friend. He works out of a record store basement and im not sure how experienced he is, but the thing looks really clean and all the pots sound a lot cleaner. Before i brought it in, the amp was making a "fuzz" type distortion at all volumes on all channels. I was hoping a good cleaning and rebiasing would fix that, but it didnt. I just used it for practice tonight, hoping maybe it would start to sound better after the tubes warmed up, but of course, it didnt. I played with it for about two hours, then after leaving it on standby for about ten minutes, i hit the power button to turn it off and i heard a faint buzzing sound like the sound of something frying and then SMOKE CAME FROM AROUND THE POWER BUTTON. :bawl: What could be wrong with this thing? im so confused. :confused:
 
#2
Typical Ampegs. They're useless, suck, and they don't even sound good. Ill take it off your hands for 50 bucks, seeing how its probably no good anymore :P

EDIT: Sorry, nothing constructive to say :3 I have no idea what might be wrong, sorry again,
 
#7
punkrockmike said:
...svt cleaned and given a clean bill of health by a "tech" who was recommended to me by a friend. He works out of a record store basement...
Click to expand...

Welp. There's yer prob'm.

While the switch contacts may have fried and let their smoke out, that's only a symptom of a bigger issue, which is excessive current draw somewhere in the amp. It's possible that the rectifier is fried - had that happen on an SWR once. Could be a power transformer partial short that was causing the distortion, then finally made full contact after some handling (cleaning).

Hard to say, but get it to a qualified tech.
 
#11
punkrockmike said:
So i just had my MTI era svt cleaned and given a clean bill of health by a "tech" who was recommended to me by a friend. He works out of a record store basement and im not sure how experienced he is, but the thing looks really clean and all the pots sound a lot cleaner. Before i brought it in, the amp was making a "fuzz" type distortion at all volumes on all channels. I was hoping a good cleaning and rebiasing would fix that, but it didnt. I just used it for practice tonight, hoping maybe it would start to sound better after the tubes warmed up, but of course, it didnt. I played with it for about two hours, then after leaving it on standby for about ten minutes, i hit the power button to turn it off and i heard a faint buzzing sound like the sound of something frying and then SMOKE CAME FROM AROUND THE POWER BUTTON. :bawl: What could be wrong with this thing? im so confused. :confused:
Click to expand...

Is that all you asked the tech to do? Did you tell him the concerns with the amp before asking for a cleaning and re-bias? The smoke does just sound like the power switch failing. As far as your initial problem you may just have a bad preamp tube or two, cleaning and re-bias won't fix that ;)
 
#12
yea i mentioned the fuzz to him. he checked all the preamp tubes and said they were in good condition. the preamp tubes are original tho, so that most likely has something to do with it. and i tried turning the amp back on after i turned it off and it turned on just fine. didnt try to play through it but the power switch works.
 
#14
Take it to a REAL tech. With tube amps this will most likely be some old guy with either gray hair or no hair since we were the last generation trained on mostly tube and the beginnings of solid state.

I went to tech school at night strictly to learn to fix my SVT and taught myself/learned how to insert master volume controls in Marshalls and Fenders before the factory made them that way. Guitarists paid me to upgrade their stuff. My SVT got new tubes once per year and the power supply was rebuilt 3 times over the course of 11 years.
 
#16
Hi.

What a hack tech, he failed to use his psychic abilities to immediately recognise the faulty power switch.

And people still wonder why no-one want's to be a tech or even look at the ignorant musicians gear. Usually expected to do that for free, no less.

Just change the power switch by yourself. You might get zapped in the process, possibly ruining some nerves in your fingers, but at least you won't get ripped of by incompetent techs who work in shady locations.

Regards
Sam
 
#18
What you learn in tech school carries over to air conditioners(controls), home wiring, that pesky dryer that stopped working, the power supply on a Yamaha DGX 505(my son's died last week, internal fuse in the "brick"), etc. Good stuff to learn even if it's not your main gig.
 
#19
Holy SVIT...

Seriously, you need to find a competent tech. Tube gear is touchy, although the great tone can be worth the hassle.

Given that you're in Minneapolis, try to find someone who is an authorized repair person for "Audio Research" stereo amps. That company is up in your area, has been making great tube stereo amps for like 30 years, and anyone who is authorized to work on their stuff can likely sort out your SVT.
 

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