4x12 Speaker Cabinet Wiring (Stereo/Mono)

[Adam79]

Hi. I have a 4x12 Marshall 1960a Cab w/ four 15ohm Celestion G12-65s; I currently have it wired for 15ohms mono. Why do companies make 15ohm speakers when every output transformer only has 16ohm taps? Anyways, onto my main question..

I want to rewire my Cab for Mono/Stereo use. I recently bought an Ampeg V4; the OT taps only run at 2, 4 or 8ohms (I talked to the tech that has my amp and he said that there isn't a 16ohm tap on the OT in the V4). Is there a way to wire the 15ohm speakers so they are compatible with said OT when running in Stereo and Mono? I assume it would be easier to install a second input jack rather than use a DPDT switch.

Would it be a dumb idea to wire only two speakers at a time (i.e. connect two speakers to their own jack, so it would be like running two 2x12s inside the 4x12 cab)?

My other amp is a Peavey VTM-120, which has speaker outputs for 2,4,8 and 16ohms. Are there any advantages or disadvantages when wiring 16ohm speakers to run at 4ohms?

Thanks,
-Adam

[morglan]

My Marshall 1960 B Vintage is wired for 4 (mono) on one jack, 16 (mono) on the other, and then by flipping the switch, I have two 8 ohm jacks in stereo (each jack runs two speakers). Ive switched it to stereo and run my Princeton Reverber through it, just using it as a 2x12. Worked fine.

[Adam79]

Originally Posted by morglan

My Marshall 1960 B Vintage is wired for 4 (mono) on one jack, 16 (mono) on the other, and then by flipping the switch, I have two 8 ohm jacks in stereo (each jack runs two speakers). Ive switched it to stereo and run my Princeton Reverber through it, just using it as a 2x12. Worked fine.

That exactly what I want to do. What kind of wiring does that involve (i.e. series, parallel, etc.)? Is there a diagram anywhere on the web that depicts your wiring scheme?

Thanks,
-Adam