Is there any real difference b/w vertical and horizontal input JCM800's?

Discussion in 'Amps and Cabs' started by Young Angus, Dec 19, 2009.


  1. Young Angus

    Young Angus Member

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    Down Under
    I did a search but couldn't turn anything up on the forum, even though this must have been discussed before somewhere.

    I'm finally looking at buying a Marshall...a JCM 800 to be exact...and I've found a great looking horizontal input one here in Australia but I remember everyone saying how the vertical input ones are a better unit than the horizontal input ones for some reason or the other.

    Are they really any different? What are the differences? I've got all the time in the world to look for the right one.
     
  2. TTripp

    TTripp Member

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    Depends on the wattage and year.

    From the Legendary Tones Marshall Shopper's Guide:
    http://www.legendarytones.com/marshallshoppers2.html

    However, during circa 1985, the design of the 100 watt JCM 800 series changed in order to cut costs. The age of the “vertical input” style of inputs as used on 2203s and 2204s for years had ended. A new “horizontal input” configuration began and this in itself only meant that the potentiometers and input jacks were now mounted directly to the printed circuit boards rather than being wired up with flying lead wires. This obviously simplified construction and in itself was NOT such a big deal, but what WAS a big deal was the change in the filtering and power supply structure of the 2203 (but NOT the 2204 - which remained unchanged) that took place later in l986 – this was also designed to reduce costs.

    Unfortunately, this latter change altered the tone of the amp. When looking at a “vertical input” JCM 800 2203 (or earlier JMP 100 watt for that matter) at the chassis, a total of six filter capacitors (those large “cans” that look like tubes) were previously present. The first of the horizontal input models were basically unaffected and examples such as the one pictured below show a design with five filter caps rather than the previous six. The primary four caps grouped together that ran as two pairs in series, was still part of the design and corresponded to Marshall's early power supply design. The circa late-1986 2203's, to reduce costs further, incorporated reduced power supply requirements and specifications and was able to eliminate one "pair" of the series-run caps, reducing the number to three filter caps total. Unfortunately these new 2203's just didn’t have the same “punch” or power levels. Sure, they were still loud, but were much more grainy and thin-sounding as they were turned up. It did NOT help that at around the same time, the U.S.A. versions of the JCM 800 series began to re-adopt the EL34 tubes, which otherwise could've been a blessing. For Marshall’s best-selling 2203 and 2204 single-channel master volume heads, the switch in tubes actually limited the tone further since the 6550 – while not as quick to break up – still provided a fuller tonal range in this particular configuration. In essence, the "three-capped" 100 watt JCM 800 was the first Marshall that did NOT necessarily sound better as the volume went up - in fact, it began to sound worse - more grainy, thin, and muddy as the volume increased. REMEMBER: THIS is simply MY opinion represented above - you may prefer the later JCM 800's as is your right to do so!
     

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