From radio shop cleanout. There's no info I can find on these. Apparently the "feed forward" design is an active very low distortion design. I popped the top and the build quality is pretty amazing. The top cover has machined channels with RFI shielding mesh in them. This was quite pricey. Untested. No info other than pulled because they were replaced with 190w version. This one has a ding on one RF connector, see pic. It's quite a heavy chunk of amp.