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Re: JCM800


 :
6/5/2000 3:31 PM
Richie{~}==::: Re: JCM800
What are the differences.. of the Mkll master volume and the First JCM 800s,  
Tonefactor? 2203??  
Besides cosmetics,there is little differences. maybe in the later models. i have a Mkll 100 watter  
77, and worked on quite a few marshalls.  
Richie{~}==:::
 
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6/5/2000 7:12 PM
Chris

"The first master volumes from 75 were actually quite different than the later ones. "  
(tonefactor)  
 
"What are the differences.. of the Mkll master volume and the First JCM 800s,  
Tonefactor? 2203??  
Besides cosmetics,there is little differences. maybe in the later models. i have a Mkll 100 watter  
77, and worked on quite a few marshalls. "  
(Richie{~}==::: )  
 
+++++++++++++++++++++++++++++++++++++++++++++++++  
The early ( 50 Watt only ? ) MasterVolumes did have a different pre-amp . Like the non-master-volumes , 2 inputs , the output of both stages through 2 mixing-resistors to the (1st)volume-pot . Little gain .  
 
(source : Doyle's and Pittman's books)  
 
Have a good time !  
 
Chris
 
6/5/2000 7:45 PM
Peter S

The early JCM 800 2203 and 2204 amplifiers were electronically identical to the '75 and later 2203 and 2204.....The only reason they changed the cosmetics was because Marshall finally got the rights back to his company from Rose Morris and they wanted to get off to a clean start with a new image.....it was a marketing strategy.....it was much cheaper than doing R&D on a whole new amp. Later on they made changes to the circuits but the first amps were identical. I've been inside hundreds of them.  
 
Peter S  
Kimerik Amplifiers
 
6/5/2000 10:26 PM
Tonefactor

quote:
"The early JCM 800 2203 and 2204 amplifiers were electronically identical to the '75 and later 2203 and 2204....."
 
 
The 75's were a completely different preamp design. The gain stages were not cascaded like the later models. They were paralleled like the 1987/1959's.
 
6/5/2000 10:33 PM
Chris

"The 75's were a completely different preamp design. The gain stages were not cascaded like the later models. They were paralleled like the 1987/1959's. "  
 
That's what I said/did mean .  
 
Chris
 
6/2/2000 9:24 PM
bicamen
I will vouch for Trace and his amps. I recently bought a 2204S from him that he modded, and I say it is a great, great sounding piece of work. He can fill you in on what he actually did, but boy it sounds fantastic!  
 
I had a '79 2204 that I changed over to EL34's to try and capture that Marshall Magic, but did no other mods (because I didn't know how) and I wasn't too happy. I ended up selling it. But, the difference between the two are night and day!
 
6/2/2000 10:20 PM
Peter S

JCM 800 Model 2203's were really the same amp as the late 70's Master Volume 2203 amp with a new cabinet and new name. Jim Marshall named them after the license plate on his Jaguar, and they changed the cosmetics to give the amp a more "modern" look. Like Trace, I've modded zillions, and these amps(like almost any early Marshall) can be made to sound really great! They make really good Non-Master volume amps too after a few mods.  
Peter S
 

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