what's the difference between JCM800 and aJCM900?
- Thread starter paultelestrat
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greendy123
New member
Re: what's the difference between JCM800 and aJCM900?
One more thing to note is that on the 2100/2500 slx models there are two knobs for gain. There is the preamp volume and gain sensitivity knobs. To my ears the preamp volume makes thicker distortion, while the gain sensitivity makes thinner distortion. The two knobs make a bunch of different tones of gain.
Oh one more thing, what kind of amp are you looking for tonally?
Hope you find the marshall amp thats for you.
JeffB said:
One more thing to note is that on the 2100/2500 slx models there are two knobs for gain. There is the preamp volume and gain sensitivity knobs. To my ears the preamp volume makes thicker distortion, while the gain sensitivity makes thinner distortion. The two knobs make a bunch of different tones of gain.
Oh one more thing, what kind of amp are you looking for tonally?
Hope you find the marshall amp thats for you.
ErikH
Well-known member
Re: what's the difference between JCM800 and aJCM900?
The 2100/2500 Mk III's (pre-SL-X) are the same way.
The way the pre-amp and gain knobs work on these models is the pre-amp volume sets the intial pre-amp gain level. The gain control sets the secondary gain level. The secondary gain level also has diodes in it's circuitry, I think there's only 2 in there.
Even though there are diodes, it's still sweet sounding because the tubes are driving so hard. The warmth can't be suppressed. Only so much gain can be accomplished with tubes. At some point, to get more, something else is needed to make it happen.
Think of it this way, lots of the tones we liked from players 10-20 years ago, their tones were a combination of tube amps and pedals (Tube Screamers, Super Overdrives). Guess what those pedals had? Diodes. Think of these JCM 900's as an amp with a built in Tube Screamer of some sort.
greendy123 said:
The 2100/2500 Mk III's (pre-SL-X) are the same way.
The way the pre-amp and gain knobs work on these models is the pre-amp volume sets the intial pre-amp gain level. The gain control sets the secondary gain level. The secondary gain level also has diodes in it's circuitry, I think there's only 2 in there.
Even though there are diodes, it's still sweet sounding because the tubes are driving so hard. The warmth can't be suppressed. Only so much gain can be accomplished with tubes. At some point, to get more, something else is needed to make it happen.
Think of it this way, lots of the tones we liked from players 10-20 years ago, their tones were a combination of tube amps and pedals (Tube Screamers, Super Overdrives). Guess what those pedals had? Diodes. Think of these JCM 900's as an amp with a built in Tube Screamer of some sort.
greendy123
New member
Re: what's the difference between JCM800 and aJCM900?
ErikH, thanks for the info. I always thought that 2100/2500 amps got there distortion for the pre-amps and didn't use diodes for distortion.
ErikH, thanks for the info. I always thought that 2100/2500 amps got there distortion for the pre-amps and didn't use diodes for distortion.
ErikH
Well-known member
Re: what's the difference between JCM800 and aJCM900?
They do get it from the pre-amp to a certain extent. The diodes are what make them high gain though. In the SL-X (Mk IV), the combination of diodes, a couple op amps, and an additional pre-amp tube make it higher gain than the Mk III.
greendy123 said:
They do get it from the pre-amp to a certain extent. The diodes are what make them high gain though. In the SL-X (Mk IV), the combination of diodes, a couple op amps, and an additional pre-amp tube make it higher gain than the Mk III.
JeffB
Let it B
Re: what's the difference between JCM800 and aJCM900?
True Dat!
But the prob is...you can't turn 'em off on a 900
For me anyway, I always just cranked my 800's, Laneys, 1987X etc and used that for my crunch rhythm sound...the diodes (peds) were only used for a boost for leads...which is fantastic cos you cut through and get a volume boost...but they also nix all the bass/balls for crunch chording if ya leave em on.
That was always my big issue with the 900s...I LIKED the extra gain, they were wonderful sounding for leads, but they didn't have the balls/low end of a 800 (non diode clipper). Jubilees and the diode clipper 800's were similar but not quite as "thin" as the 900s.
ErikH said:
True Dat!
But the prob is...you can't turn 'em off on a 900
For me anyway, I always just cranked my 800's, Laneys, 1987X etc and used that for my crunch rhythm sound...the diodes (peds) were only used for a boost for leads...which is fantastic cos you cut through and get a volume boost...but they also nix all the bass/balls for crunch chording if ya leave em on.
That was always my big issue with the 900s...I LIKED the extra gain, they were wonderful sounding for leads, but they didn't have the balls/low end of a 800 (non diode clipper). Jubilees and the diode clipper 800's were similar but not quite as "thin" as the 900s.
ErikH
Well-known member
Re: what's the difference between JCM800 and aJCM900?
Sure you can turn 'em off....put the gain at zero. You now have the same gain as the 800, no diodes. It's probably slightly less than a 800 but still, nice and crunchy.
I don't know what you mean about no balls/low end with the 900's. Now, maybe the 4100/4500 Dual Reverbs were that way and maybe the SL-X was that way but MkIII wasn't. It has tons of balls and low end. I can chug right along and rattle my drummers set from across the room. It has plenty of low end, and it's bone stock. The cabinet has something to do with it since it's closed back but I've never had a problem with the bass.
Just an FYI...the 2100/2500 MkIII models were a further development of the JCM800 2203/2004 Master Volumes and the 4100/4500 Dual Reverbs were a further development of the JCM800 2205/2210 amps.
JeffB said:True Dat!
But the prob is...you can't turn 'em off on a 900
For me anyway, I always just cranked my 800's, Laneys, 1987X etc and used that for my crunch rhythm sound...the diodes (peds) were only used for a boost for leads...which is fantastic cos you cut through and get a volume boost...but they also nix all the bass/balls for crunch chording if ya leave em on.
That was always my big issue with the 900s...I LIKED the extra gain, they were wonderful sounding for leads, but they didn't have the balls/low end of a 800 (non diode clipper). Jubilees and the diode clipper 800's were similar but not quite as "thin" as the 900s.
Sure you can turn 'em off....put the gain at zero. You now have the same gain as the 800, no diodes. It's probably slightly less than a 800 but still, nice and crunchy.
I don't know what you mean about no balls/low end with the 900's. Now, maybe the 4100/4500 Dual Reverbs were that way and maybe the SL-X was that way but MkIII wasn't. It has tons of balls and low end. I can chug right along and rattle my drummers set from across the room. It has plenty of low end, and it's bone stock. The cabinet has something to do with it since it's closed back but I've never had a problem with the bass.
Just an FYI...the 2100/2500 MkIII models were a further development of the JCM800 2203/2004 Master Volumes and the 4100/4500 Dual Reverbs were a further development of the JCM800 2205/2210 amps.
