skiman,

thank you for the explanation. The technician didn't explain it nearly as well. My (high quality) two channel preamp does not have this feature.

No, they meant adding another pair of single ended, rca inputs to the back of the amp, with a switch. Whether this is possible, or not, without compromising or changing the entire wiring approach, I do not know, nor do I think does he.

It's looking like the best method will be to relocate the 990, so I can have access to its main switch and manually plug in and pull out the 2 channel preamps out/inputs.

Any thoughts?

thanks,

John