Triple X, Englv30 Impulses Slate Samples..

I'm pretty sure that the first point about having a cab connected at all times with the amp on would have been in your Manual.

If you'd like to find a definate answer to your new question, I'd be sending Peavey an email asap if I were you.
 
Yea i would think the speaker output to mic preamp would be a bad thing. The cab being connected would not change anything for the other speaker output on the head. That would be under the same load still.

Please someone with some more info about this help us out here. This really got me thinking.....
 
Yeah you're going to put serious stress on your amp if you don't have a load connected whether it be a cabinet or a dummy load. Also the cabinet output is going to send a hell of a wattage into your Mbox!

Don't do it!

The reason it sounds better is because its going through the power amp of your head, which gives it a better tone, BUT, unless you get a dummy load with a direct out on it to do this, you will have to leave a cabinet connected and use the FX Send/Line out.

You're really lucky you haven't damaged your amp/your Mbox/yourself doing this.

This is what i always thought......