#1
ive never heard any posts about this but im just curious..0

Ill turn on my amp, leave it on standbye and give it about a minuet to warm up before i switch it to on. But sometimes, not every time, it will be pretty loud...i mean not like ear shattering, just a bit higher then what I left it on. After i play it for a little while all of a sudden the volume drops to a much lower lvl. Is this normal?

Also, although I dont know if its related, yesterday my amp got really loud after being quiet. And it started getting really muddy whenever i hit a note....like someone crumpling up paper...but with a lot of gain. Very gutteral sounding, but only when I hit a note...its never done that before, and hasnt done it since yesterday
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Faded Gibson SG Special - Black ice mod
Seymour Duncan SH-5 in bridge
B-52 AT 112
Ted Weber Mass100 attenuator
EHX Small Clone
EHX Metal Muff
DIY Modded tubescreamer
Dunlop 535Q Wah
Wax Potting tutorial
#3
well the amp is in my sig...
and I dont know i bought it used from a GC a couple weeks ago...
but is that usually what happens when the tubes go bad?
-------------------------------
Faded Gibson SG Special - Black ice mod
Seymour Duncan SH-5 in bridge
B-52 AT 112
Ted Weber Mass100 attenuator
EHX Small Clone
EHX Metal Muff
DIY Modded tubescreamer
Dunlop 535Q Wah
Wax Potting tutorial
#4
that can be a symptom of old/bad tubes, probably power tubes. Personally, I would change all the tubes, pre and power since you don't know how old they are. I would take it to a tech and have it biased also, unless you know how to do it yourself. You can usually get away without doing it, but if you want the best tone with longest tube life, you should.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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#5
I had the exact same problem with my amp...do you notice any noise coming out of the amp whenever there's nothing plugged into it?

Mine just kept producing more and more noise just like someone crumpling paper. Eventually I noticed that my volume levels were decreasing, until one day I turned the amp on and it was so quiet that I could barely hear anything when the volume cranked. I took it to an amp tech, and he's had it for 2 weeks and he still hasn't figured it out. But it was not the tubes (I have spares laying around and tried them all) and he tested the filter caps and they were fine as well. I worked with him and we tried disconnecting the reverb tank and a few other items to get the amp down to the bare essentials and we still have nothing. I'm not sure.

He's putting in a new output transformer today. Hopefully I'll get some news on it tomorrow. But it's odd, you say you just bought you amp recently...I've had mine for nearly 6 years with no problems until this.
#6
thanks for the input, but what do u mean by having it biases?
-------------------------------
Faded Gibson SG Special - Black ice mod
Seymour Duncan SH-5 in bridge
B-52 AT 112
Ted Weber Mass100 attenuator
EHX Small Clone
EHX Metal Muff
DIY Modded tubescreamer
Dunlop 535Q Wah
Wax Potting tutorial
#7
Biasing adjusts the amount of current flowing thru the tubes at idle. Bias is like the idle on a car. Too low, and your car will sound and run like crap. Too high, and it will sound good, but will burn up all your gas. When it is underbiased, it's running too hot, and can cook your tubes. It will sound great, but will shorten tube life greatly. Overbiased means they are running too cold, and can get into crossover distortion where it doesn't sound as good as it should.

BTW, cathode biased amps aren't adjustable. I mention this because I'm not that familiar with your amp. Fixed bias does not mean the same thing however, that just means you have to add/remove resistors manually rather than using a bias pot.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
amp clips
amp vids
Last edited by Erock503 at Sep 1, 2006,
#8
hmm ill call the guitar center i bought it from and see wut they have to say
-------------------------------
Faded Gibson SG Special - Black ice mod
Seymour Duncan SH-5 in bridge
B-52 AT 112
Ted Weber Mass100 attenuator
EHX Small Clone
EHX Metal Muff
DIY Modded tubescreamer
Dunlop 535Q Wah
Wax Potting tutorial
#9
you do realise your meant to turn the "on" button first , then the standby ... right ?
#10
umm ive had something similar happen to one of my older marshall jcm combo amps. its from like 89 and the thing started to sound really really bad and kept gettin quieter as i was playin. and i took the tubes out of another amp and put them in it to test and see if it was the tubes. it wasnt so i brought it in and the guy said my speaker was dying so i replaced it and its fine.

so you might want to have him check the speaker if he didnt already.