4x12 Stereo Cabinet Wiring

[PC Biz]

I picked up a used Mesa 4x12 from GC, the wired grill one from the '80s. It has a mono jack, and Mesa is sending me a stereo jack like this:

http://www.mesaboogie.com/Product_Info/Guitar Cabinets/4x12-JackplateLG.htm

Does anyone have a wiring diagram for this? Mesa says they don't, although I kinda think they do. Please help.

 

[ylo]

Hello PC Biz

You should be able to figure this out once you have the plate in hand.

Assuming 8 ohm speakers, wire each pair in parallel for 4 ohms per pair. Run each pair to one of the 4-ohm jacks.

Most likely one of these jack has a NC (normally closed) switch connection by way of a contact built-in as part of the jack. When nothing is plugged in, this connection will put the two 4-ohm pairs in series to make 8 ohm mono. The mono in and out jacks will be connected to the 4-ohm jacks but should not be used unless nothing is plugged into the 4-ohm jacks.

I may not have this exactly correct, for example the jack could use NO (normally open) instead of NC I suppose, but it should become obvious once you trace the wires. Do a sketch of your proposed wiring with the plate and switch function, and this should help sort it out.

 

[PC Biz]

Thanks for the reply. I got the jacks today, but Mesa didn't send the jack plate. They didn't charge me for it ($7), but hopefully it's on the way. I've got a call in to see what happened. More later.

 

[PC Biz]

Thanks to Boogieman75 for reminding me of this thread. Mesa did indeed have some great wiring photos, and they didn't even charge me for the jack plate! A belated thanks to Mesa. Here are the shots:

http://traveladventure.tv/mesa/412DIAG.jpg
http://traveladventure.tv/mesa/4x12_jackplate_wiring_illustration_001.jpg
http://traveladventure.tv/mesa/4x12_jackplate_wiring_illustration_002.jpg
http://traveladventure.tv/mesa/4x12_jackplate_wiring_illustration_003.jpg
http://traveladventure.tv/mesa/4x12_jackplate_wiring_illustration_004.jpg

 

[boogieman75]

Thanks to you again PC!!!

This is exactly what I was looking for

 

[Tave]

Oh, hi, I know this is an old post, but, I can't find anything atm, I have a Mesa 4x12 4FB Cabinet and I think I have the same problem with the connection with the jack plate. It has 4 jacks on it, 2 for 4 Ohms, one for 8 Ohms and the other just says Out. So, my question is, how did you connect this? Cause the pictures isn't available anymore. I hope anyone can help me with this. Thanks!