Marshall JCM 900 MK III vs. JCM 800 MKII

[charvel750]

OK, you guys gave me the lowdown on my earlier post about the difference between the JMP MK II and the JCM 800 MK II. Now onto another comparison:

The Marshall JCM 800 MK II and the Marshall JCM 900 MK III. The early MK III's were the "hi gain" models. Do they sound similar to their JCM 800 forefathers? Or are the circuits entirely different? I know the JCM 900 added an effects loop, and an extra preamp tube, but what else is different? Thanks...

[zeegler]

Doesn't the 900 have diode clipping?

[VitaminG]

yep. Except for the SL-X

[Spivonious]

Doesn't the 900 have diode clipping?

+1

As a former owner of the JCM900 MkIII, I can attest that it sounded fantastic, but definitely not like a JCM800.

Also, they don't have a clean channel, just a lead boost.

[charvel750]

What is diode clipping?

[MSGfan]

I just sold a JCM 900 SL-X, althought it sounded good, it didn't sound as good as my JMP or 800 2204 even when used with a pedal, IMHO.

[MSGfan]

OK, you guys gave me the lowdown on my earlier post about the difference between the JMP MK II and the JCM 800 MK II. Now onto another comparison:

The Marshall JCM 800 MK II and the Marshall JCM 900 MK III. The early MK III's were the "hi gain" models. Do they sound similar to their JCM 800 forefathers? Or are the circuits entirely different? I know the JCM 900 added an effects loop, and an extra preamp tube, but what else is different? Thanks...

The Marshall JCM 900 High Gain master vol. MK III came before the SL-X. It only had three 12AX7's. It was the later SL-X that had the added 12AX7, four 12AX7 tubes total.