Which JCM900 sounds most like a split channel 800?

[jimcroisdale]

Hi all,

The possibility of a RATM tribute band is looming, so I'm starting to think about how I'm going to get Tom Morello's tone.

I know he uses a 50w split channel JCM800 head, on the boost channel. However, the 800's are very fashionable right now, and the prices are sky high. On the flipside, the 900's seem cheap by comparison.

So, is there a 900 that sounds like a late model split channel 800? I know Marshall often changed their designs incrementally, so I'm thinking maybe an early model Dual Reverb or something?

Cheers,

Jim

[s_andrews89]

I have a '91 50W 900 dual reverb. And as much as I love it, I wouldn't say it sounds that much like a split channel 800. It can certainly 'do' a RATM sound with a nice powerful strat etc. But the 800s and 900s do sound different, and there really is no substitute for a decent split 800 IMO - I've been watching out for one at the right price for about 2 years now!

Will a dual reverb 900 work for you? Yes.
Will it sound like a split 800? No, not really.

You could try a 900 SLX on the first channel, but again, its just not a JCM 800. Nothing is. Hence the prices of the gorgeous things!

[mjtripper]

You can get really close with the slx (which is single channel btw - it just has two masters you can switch between) depending on how you set the two gain controls. The second one is really just like a gain/distortion level but the first one changes the tone somewhat and also how the low end responds. Using those two controls plus the triode/pentode switch in the back there are many more tones in that amp then most people realize. I think it's a vastly different amp then the first three 900 versions.

[drbob1]

IIRC the 900s almost all used silicon transistors to get distortion. This allowed a LOT more distortion at low volumes, but doesn't sound anything like the all tube distortion of an 800 cranked up. The SLX doesn't use silicon, but does have that extra gain stage, so again, a little different.

That said, if you crank the master up all the way, then just barely crack the gain knobs, you can get pretty close to the 800 sound.

[Blast9]

Silicon diodes - Yes that's right drbob1, but so does the JCM800 split channel!

Those split chan 800s are not particularly reliable and can sound grainy too - The 900 Dual Reverbs are also notoriously unreliable

IMHO better to get a JMP or the early 80s JCM 800 (or re-issue)

IMHO JCM900 SLX is your best bet - you could always substitute the "input gain" preamp tube with a lower gain 5751

-

Don't forget Tom Morello uses a Peavey 4 x 12 cab - don't know what the speakers are but it will make a huge difference to the tone

And he uses a graphic EQ as a booster (not sure if it is just on for solos?)

[s_andrews89]

Jim, Don't know where you're based, but there's a 2 channel 800 on the sound on sound readers' ads. Should state it's *not* mine, I just saw it earlier! Hopefully this doesn't contravene any rules.

Blast, I've not heard of anything with unreliable dual reverb 900s. I've had mine for about 7 years now and not had a single problem. Gigged it fairly heavily for 5 years solid until about 2 years ago too. I know others in the same boat! But we may just be the lucky ones!

[PaulOcchialini]

Build one! Marshall JCM800 / 50w Kit & replacement parts

And don't say you can't do it, if you can play the things Tom wrote, you can build this kit.