2x12 mono/stereo wiring - help...

[jimosity]

Yes, I know the search function brings up some topics, but my brain is full from trying to find my answer...

I found this schematic somewhere online and it shows a mono/stereo setup in a 2x12 cabinet using a mono jack and a stereo jack.

If I'm using 16ohm speakers, am I getting 16ohms mono and 8ohms stereo?
If this is done with two 8 ohm speakers, is it 8ohms mono and 4ohms stereo?

I have a Mesa 2x12 that is 8ohms mono, with one jack...but I would like to rewire it to allow stereo usage or mono usage.

I also have an Avatar 2x12 that I want to set up the same way...It may have 16ohm speakers in it, but I'm not positive.

Here's the diagram that I'm considering:
http://www.americanhc.us/hosting/images/speakerjacks.jpg

[ScottR]

If I'm using 16ohm speakers, am I getting 16ohms mono and 8ohms stereo?
If this is done with two 8 ohm speakers, is it 8ohms mono and 4ohms stereo?

I have a Mesa 2x12 that is 8ohms mono, with one jack...but I would like to rewire it to allow stereo usage or mono usage.


I believe that by using the diagram you posted,
You'll get whatever the individual speaker impedance is in stereo and Half the individual impedance in mono operation. there's another way to double the individual speakers impedance in mono

[John Phillips]

If I'm using 16ohm speakers, am I getting 16ohms mono and 8ohms stereo?No, the other way round - each side is 16 ohms in stereo, and the cab is 8 ohms in mono.

If this is done with two 8 ohm speakers, is it 8ohms mono and 4ohms stereo?8 each side stereo, 4 mono.

Here's the diagram that I'm considering:
http://www.americanhc.us/hosting/images/speakerjacks.jpgThis is a bad way to do it because it does not break the ground connection between the two inputs. This could cause a ground loop hum, or instability.

The best way to do it is with two jacks with switching on the ground contact as well (like the Cliff/Re-An jacks Marshall use) so the inputs are completely isolated when both are used. It's basically the same as that but with the ground connection to the right speaker passing through a switch in the right jack as well.