Dave Mail 17: The "jumper" on the Marshall Major

There was some sort of "jumper" used on the Marshall Major, between the second "Input I" and the first "Input II", as shown in the image below. What was that used for? 

Dave Lee: "If you notice, there are two volume controls on the Major. The amp was designed so two people could use one amp. And then you could control the two levels independently. 

If you "jump" the two channels, it turns the two volume knobs into a master volume and gain control. So, that's what we did."

Marshall Major 200W - with the jumper

Question by:
- Raphael Romanelli Andrade de Oliveira - Ilicínea, MG - Brazil

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