What tubes can I use for JCM 900 EL43's, 5881's, 6L6's, I have no idea.

PLEASE HELP !

i have the same sortof question. what is your ideal tube combination(power/pre-amp)

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anything but you'de have to mod if for different then stock type tubes (el34)


JJ power tubes are great, EH and Sovtek preamp tubes (AX7's) are good too

I have Sovtek 5881 power tubes. Can I not use them for the JCM 900 without getting it modded ?

The 900 comes with 5881's. Put them in but make sure their the same brand and rating.

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they run el34's stock... but marshalls can be bitchy, so if you're swapping powertubes, make sure to get the bias checked and all that.

as for brands, jj's are probably my favorite especially in the 4100... the sl-x model is higher gain though.

if gain and aggressiveness isnt a huge deal, i like the way my buddy's sounds with ruby's.

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Your saying 5881's come with the 900 but I must make sure they are the same brand that is already in my 900 ?

The 5881's come in American Marshalls. I think the EL 34's are in the Europeon ones. Look at the tubes that are in it, and see what they say on the side. I you don't have any tubes in it, get a tch guy to check and see what it takes. Or give the serial number to marsall and see what they say about what tubes it takes. I have the american 4100, and it came with Sovtek 5881's.

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5881's and EL34 are the same its just different names depending on where your at .

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i thought that 5881s are like a remake or basically the same as a 6l6.

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Hmm yeah my mistake:

5881 = 6L6
6CA7 = EL34

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I believe that you can put any kind of preamp tube in and your done.

Power tubes though must be biased and should be changed all at the same time.

try this website for some info:

Website

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The JCM900's came with 5881 (6L6) and EL34's. You need to have the amp modded to switch tube types. You can run 5881, 6L6, KT66, EL34, or 6CA7 in the JCM900 if you have the amp modded for them. You might be able to run KT88 or 6550 tubes but I'm not sure if the power transformer can handle the added current draw of those tubes. Anytime you change power tubes you need to have the amp biased regardless of the brand of tube or what the tube "salesman" tells you.
Jerry

a JCM900 with KT88's how cool would that be

Early JCM 900s especially UK versions came with EL34s until Marshall decided to use 5881s due to a short supply of EL34s. The US versions came with 5881s - Be aware of this, you can't just swap EL34 with 5881s without some slight modifications.

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