Hey all,

it's been a long while since i've posted here, but i've exhausted all my other ports of call.

my amp (marshall JCM 2000 TSL 100 head) is making a LOT of noise. I'm talkin' hiss that is much louder than any other amp that I've heard as well as a regular occurrence of clicking/popping noises. I was told to swap/replace my pre-amp tubes, but they're only 3 months old and I only use the amp once a week (more when we play shows) for a few hours. I also know that if they aren't seated properly, things can be a bit noisy, so I swapped the pre-amp tubes around anyway and made sure they were seated properly and nice and firm, but nothing changed...

I work in a music store and have managed to fix similar problems by swapping the pre amp tubes around or replacing the first one with a new one, but this just isn't making a difference - could it perhaps be that the base for the valve isn't soldered properly/dry solder joint? I consider myself to be very handy with a soldering iron, so I'll crack it open and have a look, but I was just wondering if anyone has had a similar problem with any other amp and if so, what fixed it.

I've tried removing everything aside from the guitar from my signal path and playing it through different cabs and testing my cab with different heads and by deduction, if found that it has to be the head.



Cheers

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Ok,

So have you actually swapped out the preamp tubes with different ones? Tubes can go bad for many reasons (temperature changes, vibrations, etc). So don't rule out the fact that the tubes are only 3 mo old and barely used. Seems unlikely but definitely probable. Also don't rule out the power tubes either. I'm sure either ones could possibly cause similar symptoms (don't hold me to that). Do they warranty new Marshall amps? I wouldn't solder crap if it was under warranty, but if not, then it wouldn't hurt to look for weak solder joints or cracks in any joint as that can cause alot of electrical noise in the circuit.

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preamp tubes definately.

Also, rebias that mofo. Bad bias makes alot of noise. But popping is ALWAYS preamp tubes.

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It defintately doesn't have warranty anymore - i know its about 4 years old.

Any ideas on a good place to find a "how to" for biasing. That's pretty much the only thing i've never done myself before (i was an electrician for 3 years). I had it re-tubed and re-biased at the same time as I did the pre-amp tubes. It's fitted with KT77's and was told that it runs fine... maybe that's where a fair bit of the noise (louder hiss) is coming from.

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oh yeah...

I tried swapping all of the pre-amp tubes to different positions as well as swapping them for new ones...

also ever since i put my noise suppressor in the effects loop - I've lost all of my effects - they just don't seem to work... Probably cause the N-S is ater everything and is just sucking it all out of it.

my chain runs as such:

gtr
> (via lead or wireless) Tuner pedal
>Wah Pedal
>Loop switch
>Amp

Loop Switch send
> Boss DD-20
> Phaser
> Tremolo pedal
> Chorus
> Lo-Fi
> Loop Switch return

amp fx loop > NS-2

I use this cause I didn't get the footswitch and thus I can't turn the fx loop on and off at will without it - so I run a loop/signal router before the amp for my effects.

I put the NS-2 in the amps loop to cull some of the noise (which sort of works... not all of it, but it's much less noticable) but now all my effects don't have any... well... effect when I kick the loop pedal on - probably due to the NS-2.

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i have kt77s in my tsl and it didnt make the hiss anylouder, heres a 'how to bias vid' for the dsl/tsl http://www.youtube.com/watch?v=LzFuUBERc_4

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cheers guitar_demon - much appreciated

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