I had a DH200 for over 20 years in my main system. It's pretty good unit. I never did a thing to it as far as maintenance goes. It worked flawlessly for the entire time I had it. It produces a lot of clean power to your speakers. I never thought it was harsh, grainy or bloated. It also bettered a newer, highly regarded high wattage/high current amp, in my system. So I sold that unit. The Hafler got a second life in my brother's system. This thing has been going for 24 years! Not bad.
You can check out www.avahifi.com and www.musicalconcepts.com. Both of these sites do Hafler upgrades and mods, so they'll have some good info regarding that. Frank at avahifi told me he has never heard of a transformer from the DH200 burning out. Good to know. I wouldn't do anything until you install the units into your system and see if you like them. Then decide for yourself.
Enjoy 'em.
You can check out www.avahifi.com and www.musicalconcepts.com. Both of these sites do Hafler upgrades and mods, so they'll have some good info regarding that. Frank at avahifi told me he has never heard of a transformer from the DH200 burning out. Good to know. I wouldn't do anything until you install the units into your system and see if you like them. Then decide for yourself.
Enjoy 'em.