Before my Dynakit ST-70 I ran Hafler amps for over 30 years. I always enjoyed the smooth mosfet sound. I was given two DH-220's last year and finally got around to begin restoration. I installed Musical Concepts PA6 driver boards with larger power supply caps in the first one. I knew the sound would be great because I did the same with my DH-500 over 20 years ago. The 2nd DH-220 is going to be a bone stock restoration.These are great budget amps with incredible and very respectable specs. They sound wonderful.