I have a pretty rare Philips 591 integrated amp, 30 watts a side, all DIN on rear panel, looks pretty solidly built, vintage early 1970s. Has the "Philips HiFi International" logo on a brushed strip at the front of the top. It has a few scratches on the wood side panels but its in good shape other than that. Works well. I want to sell it to make more $$ for Marantz stuff, what do you think it's worth? It would be thoroughly cleaned for sale, obviously. I've never seen another one in my life, and I found ONE picture doing internet searching.