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diy tube amp problem
diy tube amp problem
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Old 14th June 2006, 06:31 PM   #1
ectobia is offline ectobia  United States
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Join Date: May 2006
Default diy tube amp problem

I changed 300b tubes with new ones after the tube amp was unplugged from the wall for a while, and smoke started coming out from the tubes,then I turned it off and unplugged it, I made sure all the tubes were plugged in the socket before turning it on. Then I tried it again and hear a very strange noise coming from the amp. So I took them out and then I noticed brown burn marks at the top of the tubes. I put the original ones back in and they didn't burn but I heard the strange noise coming from the tube amp so I shut it off immediately. What should I do? Is this could be caused by a bad tube socket, or just a bad solder point.. anything else that could cause this problem?

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Old 14th June 2006, 07:04 PM   #2
alexmoose is offline alexmoose  United States
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Location: Michigan
what kind of noise was it? was it a low hum? are you using AC, or DC heaters?
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Old 14th June 2006, 08:12 PM   #3
Kyle K is offline Kyle K  United States
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Join Date: May 2003
Location: Mililani, HI
Some new production 4-pin sockets have holes that are large enough to plug a tube in the wrong way. Could that have happened?
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Old 14th June 2006, 09:36 PM   #4
selfwilly is offline selfwilly  United States
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Join Date: Jan 2005
Location: new england
my first thought too ,kyle, i hate to say it, i've done this! when i saw the current meter instantly slam over to max rather than the slowish climb up , i shut it down! the tube plays to this day-good advertising for jj!
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Old 14th June 2006, 09:50 PM   #5
teemuk is offline teemuk  Finland
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Join Date: Nov 2004
Location: Suomi, Finland
Judged by ectobia´s description I think that the tubes were possibly bad, plugged the wrong way around or whatever. This caused a short somewhere in the circuit - which still exists - and now the high current in the mains transformer "resonates" its windings, thus the "strange sound from the amp".
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