I recently purchased a wonderful tube integrated (Audiomat) that has 5 line inputs but no phono. I have a second solid state integrated (Audiolab 8000A) with a good MM phono stage, and this has pre-amp out. Can I connect the Audiolab to the phono-sans Audiomat via one of its line inputs and use as an outboard phono stage? Will this in anyway damage the Audiomat?
As described, no problem: use Audiolab's phono & pre-out to Audiomat. Take care to keep the master volume down until you find the right settings (the pre-out should go through the Audiolab's volume pot).
By doing that you're going to send the phono signal through two line stages. It shouldn't cause any problems for either piece of equipment, but you're going to get better sound with a dedicated phono stage connected directly to the Audiomat. Why don't you sell the Audiolab and buy a phono preamp?