HELP!!! Muddy Marshall Tsl100

[Tommy_b69]

Hi folks, I am in big trouble, my Marshall sounds like crap in the lead channel when the gain is more than 7, it gets muddy with no clear tones anymore and no definition, really sucks, also when I use it loud, it sounds death, no color, I change the power tubes with svetlanas el34, got better but the problem wasn't solved.

I didn't rebias the plate, so could that be the trouble, or maybe bad preamp tubes?, I want to recover my Marshall tone, I bought the amp used, it's the first series 98' in the serial number.

[Kommerzbassist]

Re: HELP!!! Muddy Marshall Tsl100

Hello and welcome to the forums...
This sounds weird, I have a TSL60 and it actually doesn't behave like yours does... I wouldn't point this to the power tubes beeing biased wrong (too cold) actually (if it was like that before with the others too)... more the preamp tubes... try switching them around to see if that changes the sound in a good way... preferably V1 (the one farthest away from the power tubes... should have a little metal cover) with one of the others, as this one has most impact on the sound... but try swapping around the others too. (if that does a drastic change you have a bad preamp tube that should be replaced)

[Tommy_b69]

Re: HELP!!! Muddy Marshall Tsl100

Thanks man, yes it sounded wrong since i got it home, i guess that I move it to fast and din't let the tubes cold down after I test it loud, really loud, so when I got home one power tube was broken, so I order svetlana's quadmatched from Ebay, after I got the tubes I replaced them but I didn't rebias the tubes because I wasn't aware off doing it, I trade my Peavy XXX for this TSL and Peavy XXX amps doen't need rebias.

I also just order the JJ 12AX7 repamp tubes because I don't know if the prior owner change them, and I know that preamp tubes last twice the time off a power tube but my amp is a 98' model, I haven't found a good tech here in México city, and I don't know what the hell is wrong with it!!!

[Marcel]

Re: HELP!!! Muddy Marshall Tsl100

Check Bias! Maybe too hot?!?

Try a tube screamer in front!

Which cab?

[Kommerzbassist]

Re: HELP!!! Muddy Marshall Tsl100

So it actually sounded good when you tested it, but bad after you installed the new power tube? Then of course it's like to be the power tubes fault... Just if you didn't already know, you should use matched sets for power tubes, not just replace one... but looks like oyu did that anyway. And you need to bias them to the right point and fine adjust them by ear, or if you don't feel comfortable with that, let an amp tech do the work. (if you can find one)
Replacing the preamp tubes on a used amp can't be too bad either though, so a whole retubing sounds like a good idea...

[Kommerzbassist]

Re: HELP!!! Muddy Marshall Tsl100

Check Bias! Maybe too hot?!?

Rather too cold with the symptoms he has...