Using Two Amps with One Cab?

[technik]

Hi guys,
I have two amp heads and 1 cab (8ohms). Is that ok if I let 2 heads "on" at the same time and each amp connect to the cab. Then I'll just use an A/B Box from my guitar to each of the head. So, everytime I want to use a specific head, I'll just step on the A/B box, and the sound goes out from the cab?

Will that harm the amp or the cab?

thanks

[John Phillips]

DO NOT DO THAT!

You'll fry one or both amps.

You must never connect the outputs of two amps together - whether or not both of them are receiving a signal, either directly or via a cab.

You can't safely switch between the amps and the cab with a simple A/B box either.

The only way you can do this sort of thing is with a purpose-designed amp-switching system, which mutes the amp that is not being used and connects it to a dummy load, and also protects both amps while the switching is happening. This needs to be a system that controls both the outputs and the inputs to both amps.

These aren't cheap unfortunately - there are two systems that I know of, made by Axxess and Radial, although I haven't used either of them personally.

[technik]

Thank you so much John, I appreciate ur help!!