Marshall jcm900 dual reverb question

[fenderiarhs]

it's a friend of mine's amp and we found it carries 5881 tubes.I don't know if these are supposed to be the right tubes for a marshall.....i thought the el34 would be better so we both said if it was possible to change to el34 insted of the 5881. Will it sound better and more marshally with them?
Also one other important question is in case there is a benefit from changing to el34 what should we do?How is it done? It needs rebiasing??(I don't know how to rebias as i always used mesa dc5 which is fixed bias).Any other info regarding the operation?
Thanks

 

[Bludave]

Re: Marshall jcm900 dual reverb question

I have a 50W 900 combo. I am almost 100% sure that Amp came with EL34's, I will check and see whan I get a chance. As far as Biasing goes there are meters you can buy today that will make it relativley easy to do. I would recommend taking the Amp to a tech, and have all the tubes checked. If the power section has been changed, chances are the preamps were also. The 5881 tubes are not inferior, they just sound different. The Marshall 800 2203 I think was tubed with these tubes, and that Amp is considered to be a legendary Amp. As far as all the tecno stuff if you want to fix this yourself, I will let someone else guide you as I don't really work on Amps.

 

[EL WHOPPO]

Re: Marshall jcm900 dual reverb question

They actually came with both. Mine has the 5881's (6L6), and I bought it un-modded from the original owner.
From what I heard, the EL34's are for the American market, and the 6L6's are for the rest of the world.