200, 400 or 700? It's been 40 years but I had an original 400 that was great and issue free. Upgraded to a 700 Series II and I had a lot of issues, so many that PL sent me a replacement. The new replacement had a slight hum so I got rid of it immediately. My brother had a 700B that was excellent and issue free. If you do go PL, I recommend using it with 8ohm nominal speakers. Also there is a company called White Oak that offers highly regarded rebuilds that address the known problem areas with PL amps. Here is one for sale now from Music Technology in Virginia.