Hafler DH 500 update?

It's hard to say not knowing the rest of the system.

That said, stock, the DH500 is not very good. In it's day, and I had one, the little Amber 70 kicked it in the butt. The biggest problem was the Hafler sounded anemic. No dynamics. Sounded like a 50 watt amplifier rather than 500.

I had also gone the Musical Concept routs, though with an earlier DH200, rather than 500. John's kits do improve the sound but it's still going to sound like a solid-state amplifier from that period and not up to the standards of equipment being built today. So if this fits into your budget, then you consider the update. Otherwise, I'd save my money and look elsewhere--but as I said in the beginning--it all depends on the speakers being used, etc.

I am using this amp with a set of Meadowlark Swift. These are very easy to drive and the Hafler does a reasonable job. I use a Red Wine Audio modded Squeezebox 2 as a source and a Sunfire Reference preamp as a control unit. For almost zero investment, it ain't bad. I have heard worse for a lot more money. I am basically a tube man so the limitations especially in the midrange are apparent. My experience with alot of these large power amps is that they sound better when played louder than I normally listen. Tube in contrast seem to retain there dynamics at a lower volume level..Does anyone else feel the same?

Well Elizabeth, I consider my purchase of the DH500 as one of my two worst decisions in my 35 years of audio (the other being the Adcom GFA-1 that couldn't drive anything but a 8 ohm speaker and would overheat and constantly shut down driving my DQ10s :( ). The 500 was a step down sonically from the 200. Perhaps they cut corners when it came to the power supply and upgrading that might improve the sound of the DH500. I kinda doubt it though.

"Tube in contrast seem to retain there dynamics at a lower volume level..Does anyone else feel the same?"

I do, and the lower I go, the more "single ended" seems to be the best. There are exceptions of course. I was surprised at how good my ss Pass XA.5's sound a low volumes. I read Nelsons description of the circuit and guess what? He biases these to run "single ended" at very low volumes. Even at louder volumes, you have times where the music decays into silence.