I have a stunning secondary system amp which is Sunfire Symphonic Reference. It throws 250W/8Ohms and doubles at 4Ohms throughout full frequency range! It's hard to get it used because nobody sells it.
If you still want to aim for vintage gear I'd recommend Nakamichi PA/7 which probably would not run any cheaper than Sunfire I mentioned.
If you still want to aim for vintage gear I'd recommend Nakamichi PA/7 which probably would not run any cheaper than Sunfire I mentioned.