#1
ok so ive never played this amp but i want to just ask, whats the deal with it? why do they make it id the jcm 800 seems to be a much more sucessful amp? do they differ sound wise? is there a particular style the jcm 900 is made for?

im just curious about this amp as i have never really heard much about it
#2
some people don't like it because of the diode clipping.
Jumping on dat gear sig train.
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Blackstar ID:Core Beam
#3
Well if you're talking about the standard dual reverb jcm900s, the reason people dislike them is that they added a solid state clipping diode gain stage into the amp which makes it sound thin compared to the 800s

Not all jcm900s are hated though..
infact the JCM900 slx replaced that solid state stage with an extra tube gain stage instead so alot of people like those.

I'm sure someone can expand on this more then me since its 4:15am and i've been subnetting stuff for my college project all night but thats the basic jist of it.
#5
yes.
Jumping on dat gear sig train.
PRS Hollowbody II / BKP Warpigs
Strandberg OS6T / BKP Aftermath
Strandberg OS7 / Lace Poopsticks
Skervesen Raptor 7FF / BKP Warpigs
Skervesen Raptor 6 NTB / BKP Juggernauts
Hapas Sludge 7 FF / Hapas Leviathan
Anderson Baritom / Motorcity Nuke BKP Sinner Anderson H2+
Warmoth Baritone / BKP Piledriver
Ibanez Rg2120x / BKP Nailbomb

Blackstar ID:Core Beam
#7
Pretty sure JCM800 2205/2210 and Jubilees all have diode clipping too? Dont see people bitching about Jubilees diodes?

Play a couple yourself and see if you like them.
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Framus Cobra
Marshall JCM800 2203 - 1960A

Pedals:

Crybaby 535Q
Rockbox Boiling Point Overdrive
#9
Now this brings about another question, do JCM900 Clones such as the Bugera 1990, have diode clipping?
#10
Whatever is or isn't in it; they made it to have more "gain" than the JCM 800 amps and hoped it would compete with some of the raunchier amps that had become popular at the time. Apparently enough people like it that Marshall still makes it (at least, they still make one incarnation of it). As long as there is a market for it; they'll make it.
"Maybe this world is another planet's hell?" - Aldous Huxley
#12
Isn't it as simple as getting a soldering iron to remove the diodes that are clipping?
#13
Quote by farmosh203
Isn't it as simple as getting a soldering iron to remove the diodes that are clipping?


This, I had a similar thought after posting earlier. Can it be done. Has anyone ever tried it?
#14
it's a good amp for a british high gain sound, in my opinion, even though a lot of people hate on it
periphery/bulb!

gear:
Ibanez RG7321 w/ D-sonic in bridge

Peavey 5150 mk ii & b52 4x12 cab

line 6 podxt for recording

Quote by AsOneIStand
Head and Cab for $130? You don't need a head and cabinet, you need a psychological examination.
#15
The JCM900 4100 not just an 800 with clipping diodes, it has 15 opamps providing gain and 9 clipping diodes to add distortion.
They have one use and one use only, punk. That's all the do and they do it exceedingly well.

To remove the clipping diodes on channel one you remove (lift one end) of the red LED's.
To remove the clipping diodes from the boost "channel" you cut a track and replace the bridge/diode network with a 100K resistor.
Doing this makes them sound better but it doesn't turn them into a JCM800 by any stretch of the imagination.
I left the LED's intact on mine because they do give it a punky sound. It is a punk amp so all I wanted to do was improve the lead boost so I removed BR2/D10.
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Last edited by Cathbard at Mar 19, 2011,
#16
Quote by Cathbard
The JCM900 4100 not just an 800 with clipping diodes, it has 15 opamps providing gain and 9 clipping diodes to add distortion.
They have one use and one use only, punk. That's all the do and they do it exceedingly well.

To remove the clipping diodes on channel one you remove (lift one end) of the red LED's.
To remove the clipping diodes from the boost "channel" you cut a track and replace the bridge/diode network with a 100K resistor.
Doing this makes them sound better but it doesn't turn them into a JCM800 by any stretch of the imagination.
I left the LED's intact on mine because they do give it a punky sound. It is a punk amp so all I wanted to do was improve the lead boost so I removed BR2/D10.


since the amp relies on diodes for gain, wouldn't taking them out make it tough to get a sufficient amount of distortion?
periphery/bulb!

gear:
Ibanez RG7321 w/ D-sonic in bridge

Peavey 5150 mk ii & b52 4x12 cab

line 6 podxt for recording

Quote by AsOneIStand
Head and Cab for $130? You don't need a head and cabinet, you need a psychological examination.