I am new to tube equipment. Is hiss a sign of old tubes?

  • Thread starter Thread starter Malpine Walis
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Malpine Walis

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OK, I got a sweet deal on a groove tubes trio preamp ($250 used). The only thing that I know about the history of the unit is that it sat in someone's basement for many years. I have no idea where it stood when it stopped being used.

Now it is putting out some white noise on two of the three channels. Given the little bit that I know, I really can't say if this is normal or not. I can tame it with a compressor/noise gate but I have to wonder if I should have to. Mind you, retubing will cost a fair bit of cash, so if I don't need to do that, I will not. The thing is that I don't really know how to tell if I need new tubes.

So the major question would be if white noise is a sign of bad tubes.

Then too, there would be a minor question, which is what are the signs of bad tubes?
 
With your amp plugged in, take a pencil and tap each tube. It the tube is bad it will make a microphonic crackling sound. Oh, and another thing, be careful, there's a lot of juice flowing through tube amps. Don't touch the circuitry.
 
the fact that it's only on two of three should be encouraging to you... though it could well drive ya nutz finding it... try to figure out what it is about the third ch that's diff... if you can isolate tubes that are only used in the clean ch then you can sub them in the dirty ch to rule out tubes as well... good luck keep us posted and try to find a schemo for it...


here's one for the triaxis... dont know if it's close to what you've got...
http://www.freeinfosociety.com/electronics/schemview.php?id=298

another... http://www.tubefreak.com/mesa.htm#triaxis

again... http://www.schematicheaven.com/mesaboogie.htm



i'm not finding anything that says trio... and cant say i remember one either... are ya sure thats what it is???
 
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guitar zero said:
With your amp plugged in, take a pencil and tap each tube. It the tube is bad it will make a microphonic crackling sound. Oh, and another thing, be careful, there's a lot of juice flowing through tube amps. Don't touch the circuitry.
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Sorry, misread the question. Thought we were talking about a tube guitar amp.
Nevermind.
 
Mmmkay andy... who left the cave door open again???
 
dementedchord said:
Mmmkay andy... who left the cave door open again???
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Exactly!

Andy needs to keep his bullshit rhetoiric and his self absorbed sense of humor in the Cave where it belongs.

Andy doesn't appear to be very intelligent.... nor familiar with recording equipment.
 
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