2203 1978 issue

[krokit]

Hey guys my 1978 2203 is sounding great since I modded it last year but after about 10 mins of being on it sounds as if the gain has been turned down a little and is a tad duller! Im sure the tubes are fine and wondered if it may be the caps which are the originals? Cheers

 

[charveldan]

It could be filter caps or tubes or alot of other things.

I have two 1978's the ive had work done to and they rock, find a good reliable amp tech and give your Marshall a tune-up.

 

[NewReligion]

Hey guys my 1978 2203 is sounding great since I modded it last year but after about 10 mins of being on it sounds as if the gain has been turned down a little and is a tad duller! Im sure the tubes are fine and wondered if it may be the caps which are the originals? Cheers

Are you sure that it is not the fact that your ears are becoming acclimated to the sound and freq's?

I am not being a smart ass, this is something to consider. I get real screwed up when I start comparing different heads.

I have this issue at times. I've been dealing with this phenomenon for nearly 40 years.


Respectfully, NR

 

[demonufo]

Are you sure that it is not the fact that your ears are becoming acclimated to the sound and freq's?

I am not being a smart ass, this is something to consider. I get real screwed up when I start comparing different heads.

I have this issue at times. I've been dealing with this phenomenon for nearly 40 years.

Yup. Me too. Especially at gigs. If I have a mid set break, I always suffer this.

 

[scat7s]

my money is on worn power tubes.

 

[Australian]

my money is on worn power tubes.

^this. Power Tubes.

 

[krokit]

Thanks guys..! Def not my ears as its the same when I play it quiet at home...! So output tubes could be the culprit? Is there a way of checking the tubes before I buy new ones? Cheers

 

[scat7s]

you could monitor the bias, if you say it changes after 10 minutes or so, you might see that reflected in your bias measurement. not a guarantee, but its def possible.

the best way to check is to install a known good set of power tubes, its smart to have spares on hand anyway, if possible. tubes can fail at any time. and their symptoms can vary...if it turns out to be another issue, and your power tubes are good, you still havent lost anything. you now have a spare set when you need them. and you will need them eventually.

 

[krokit]

you could monitor the bias, if you say it changes after 10 minutes or so, you might see that reflected in your bias measurement. not a guarantee, but its def possible.

the best way to check is to install a known good set of power tubes, its smart to have spares on hand anyway, if possible. tubes can fail at any time. and their symptoms can vary...if it turns out to be another issue, and your power tubes are good, you still havent lost anything. you now have a spare set when you need them. and you will need them eventually.

Thanks mate.. Yeah, the tech at the studio where I work is gonna do something like that! He's got scopes and stuff, so he's gonna monitor the measurements over a period of time and get back to me. Missin ma amp though!

 

[yafal]

Not just power tubes! Can be one of the 12Ax7/ECC83 also. Dont forget to test those!

 

[shooto]

It could be filter caps or tubes or alot of other things.

I have two 1978's the ive had work done to and they rock, find a good reliable amp tech and give your Marshall a tune-up.

^ that's hot