Yes, I sold a BM6500 to a customer who was going to use it to feed a QUAD power amp via powerlink. It was a couple of years ago and as far as I know, all went well.
I remember that we arranged to meet at a farmer's grass air strip. The guy arrived in his private plane, collected and paid for the amp and off he flew. Had a few phone calls about making up a suitable cable but after that nothing.
I have personally used a BC9000 as a pre amp to feed a QUAD with quite remarkable results. The combination made a pair of RL140's come to life in spectacular fashion.