David Hafler got the message. I was a Hafler dealer and I loved the sound of the products, esp. the MOSFET power amp the DH200. I still use 2 of them. But we complained about the very sharp* fins so the biggest improvement (IMHO) was the beautifully rounded heatsinks on the DH220. I have 5 of those and they are all still warming up my home theater. The MOSFETS do run hot. Reliable... of the 7 amps (35-38 years old in use 40-60 hours/week) only one issue occurred. A defective fuse. NOT blown, the fuse wire became detached from an end cap.
* VERY sharp. I assembled over 20 of these for one project and still have painful memories of having to move them out to the client’s home.
* VERY sharp. I assembled over 20 of these for one project and still have painful memories of having to move them out to the client’s home.