GibsonSlash

Hi,

Pardon me for this noob question.

I've seen two different kinds of switches ("red" & "black" Switches VS Old-Style Switches with red square light) on JCM 800 (2203/2204 models).

Red & Black switches:


Old-Style switches with red square light:


I've seen them both were made at the same year (1983) with Vertical Inputs.
What differences are between these two models of switches?

Another question, since what year JCM800 uses Horizontal Inputs?
I heard stay away from Horizontal Inputs and Vertical Inputs are more sought after. Why is that?

Thanks

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felim

Regarding the switches, I think the Canadian models needed to have the toggle switches (what you refer to as the ones with the square light) to comply with whatever electronic safety rules they had there.

Other countries models had the rocker switches, red power switch and black standby.

I'm open to correction though.

mmorse

You are correct!

GibsonSlash

Thank you

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steelhorse

Love your family avatar there Gibson! Very nice.

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RED4100

the difference between the vertical and horizontal inputs it that horizontal are mounted to the PCB and the vertical inputs are chassis mounted.

GibsonSlash

Thanks, but yours sure are much much nicer. Every man dream.

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GibsonSlash

So is this what causing sound clipping at high gain?

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PaoloJM

This wouldn't affect the tone but, as I mentioned on the LP forum post, the horizontal input amps started using power resistors instead of chokes in the power supply which is more likely to affect the tone of the amp. I think someone else also mentioned that they started using different power valves on American models, 6500s, at this time too which would also contribute to the change in tone.

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mmorse

Marshall went to horizontal inputs (PCB mount) around 1985 for cost cutting reasons. The change did not affect tone at all. However, at the same time as that change, Marshall cut down on the filter caps from 6 to 3 on the 100 watters (2203). This did affect the tone for the worse. No cap change happened on the 50 watters as they always had 3 filter caps. So the who;e vertical vs horizontal issue really only applies to 100 watters.

mmorse

The company that distributed Marshall in the US changed out the tubes from 34s to 6550s. They seemed to survive the trip better than 34s. And this was done in the 70's. Long before the input change. In fact, the agreement with that distributor ended in '81 and Marshall marked the occasion by changing the name from JMP to JCM 800 and changed the styling of the head cabs.

PaoloJM

What you're saying about Rose Morris and the 6550s may well be true, I wasn't too sure on the dates on that (it was something I had read in someone else's post), but the choke piece is correct according to the Doyle book.

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