JVM Forum

I'm confused with the labelling on the back of the 1960A cab.

I understand that the cab can be 2x8 ohms in stereo, and 16 ohms in mono. It also says 4 ohms in mono.
Seeing that I don't want to make my head or speakers go KABOOM, I'll check with you guys first.

If I plug one end of the speaker cable in the 4ohm input, and the other end in the 1x4 (top left) jack on my head I should be fine? What is this input used for, anyway?

With those newer stereo speaker switches the cab can be 16Ω mono; 8Ω+8Ω stereo; or 4Ω mono.
In regards to the "mono 4Ω" wiring, it is a combination of parallel and series to become 4Ω mono.

I'm not a tech, but I know that different ohmage will draw from different parts of the transformer.
Its one of those things to try and see if you like it better.
Let us know if you think its darker, less highs.

4 ohm or 16 ohm it doesn't matter...
with 16ohm, you are using the total amount of windings of the OT's secondary
with the 4ohm output just a part of those windings...
this doesn't make any difference to the OT, the valves or your sound whatsoever...
the valves are seeing the same load and the speakers are getting the same amount of power... that's the only purpose of different impedance settings on your amp... as you know the impedance has to be matched, so the valves are getting the proper amount of load... without a proper load, valve's can short out, because the amount of current flowing trough them can be too high...
and OT's don't like shorting valves...

Ah found it, this is the thread I was looking for:

viewtopic.php?f=1&t=61&hilit=4+ohms+mono

Thanks for that... I was just checking to see if it's safe. Thanks for the tech side explanation, dooley. I'll try it tomorrow, even if it's the same, just for the sake of trying