JCM 900

dubele · Posted: Mon Mar 05, 2007 9:42 am Post subject: JCM 900

Hello. I am new here.

I have a Marshall JCM 900 with a Marshall 1960 Lead 4 x 12 cabinet. I was hoping someone could expain the following:

1) On the back of the head, there is a high/low switch. What is this for and when would I use it?
2) On the back of the cabinet, I have 2 inputs: 4 ohm and 16 ohm. Also, the 4 ohm input also says 8 ohm right and the 16 ohm says 8 ohm left. How do you use these and in what situation?
3) Mono/Stereo toggle switch. What is this for and when would I use it?

Also, sort of related.....I have a Fender Deluxe Reverb. Is there anyway I can plug my DDRI into my Marshall Cab? I guess I would be using the Marshall Cab as an extension speaker.

Thanks,

Doug

waldo · Posted: Wed Jun 27, 2007 2:27 am Post subject:

1) the hi-low switch is for 50W or 100W - if you choose low then 2 main tubes are not used - however you must change the impedance from 16 ohm to 8 ohm.

2) your speaker box is either mono OR stereo. In MONO mode you can use the left input 16 ohm OR the right for 4 ohm - in STEREO mode you must use both inputs which will give you 8 ohms

3) sorry - do not know Fender model.

Cheers brett