Stereo setting on JCM900 1960b + '71 JMP

Jenovaslegacy · 10-22-2009, 07:58 AM

Okay, so another potentially stupid question (though I've asked enough already this one can't do much more harm).

I am running my '71 JMP through a recently acquired 1960b JCM900 Cab, and having problems getitng the tone out of it that I have enjoyed with other cabs/speakers. I have noticed there is a 'Stereo' switch round back of the cab (have only played it on the mono so far) right next to the input, and I am curious to see if hitting this switch would have any effect on the tone. However I am concerned that in doing this that the head/cab/both wouldn't handle it and I could blow something.

Anyone got any thoughts here?

American Viking · 10-22-2009, 11:01 AM

Stereo means and two Mono means one in the simplest terms. You only have one amp so Stereo is not an option for you. All that switch does is split the cabinet in half so you are only using two speakers on the right or left depending on which input you plug into. It's also dedicated 8ohms per side when switched to Stereo. This is so you can use two amps in one cabinet.

Buggs.Crosby · 10-22-2009, 12:32 PM

If you move that switch to stereo make sure you move switch to the 8ohm setting on the head or you will blow your output tranny....you can run a 16ohm cab on the 8ohm input but not the other way around...but matching the Impedance is always the best bet

10-22-2009, 07:58 AM	#1 (permalink)
Jenovaslegacy Member Join Date: Sep 2009 Location: Midlands, UK Posts: 62	Stereo setting on JCM900 1960b + '71 JMP Okay, so another potentially stupid question (though I've asked enough already this one can't do much more harm). I am running my '71 JMP through a recently acquired 1960b JCM900 Cab, and having problems getitng the tone out of it that I have enjoyed with other cabs/speakers. I have noticed there is a 'Stereo' switch round back of the cab (have only played it on the mono so far) right next to the input, and I am curious to see if hitting this switch would have any effect on the tone. However I am concerned that in doing this that the head/cab/both wouldn't handle it and I could blow something. Anyone got any thoughts here? __________________ 1971 JMP 50w 1960b 4x12 Cab Zoom G2 FX Westfield E4000 Les Paul Solid Body

10-22-2009, 11:01 AM	#2 (permalink)
American Viking Senior Member Join Date: Jan 2009 Location: RICHMOND, VIRGINIA Posts: 2,031	Re: Stereo setting on JCM900 1960b + '71 JMP Stereo means and two Mono means one in the simplest terms. You only have one amp so Stereo is not an option for you. All that switch does is split the cabinet in half so you are only using two speakers on the right or left depending on which input you plug into. It's also dedicated 8ohms per side when switched to Stereo. This is so you can use two amps in one cabinet. __________________ Transformers inside amplifiers were not originally designed to be in there, and the tube was not created for the guitar amp. ANY recommended idle current is a guideline and in no way a necessary requirement. There is no skeleton key for any tube amp.

10-22-2009, 12:32 PM	#3 (permalink)
Buggs.Crosby Senior Member Join Date: May 2009 Posts: 478	Re: Stereo setting on JCM900 1960b + '71 JMP If you move that switch to stereo make sure you move switch to the 8ohm setting on the head or you will blow your output tranny....you can run a 16ohm cab on the 8ohm input but not the other way around...but matching the Impedance is always the best bet

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