I posted recently that I recently became the new owner of an old Hafler 220 amplifier - see my original post here:
http://forums.audioholics.com/forums/showthread.php?t=33396
Today I got to spend some time comparing my Denon to the Hafler. I used Patricia Barber's Modern Cool, track 11 (Postmodern Blues) since I'm familiar with it, and it seems to be a common album used for critical listening. I listened to the song several times on the Denon, on the Hafler, and at the end I paired them up and bi-amped my speakers (they were already biwired, for no good reason, so I had the cables).
I initially expected the Hafler to sound better than the Denon. It has a bit more power, and uses MOSFETs, which I kept reading good things about. But surprisingly, the two sounded really close, and I slightly preferred the Denon. I felt the Denon had a bit more presence compared to the Hafler, like it actually had more power behind it and wasn't trying so hard. It also sounded slightly more natural to me, although after listening to it for 7 years I may have simply gotten used to it. The largest differences came out around 3:30 into the song, where the bass player spends some alone time. With the Denon, the sound of the strings hitting the instrument while they played their intended notes felt like a natural part of the sound, while with the Hafler they sounded more like the sounds were from two different instruments. It wasn't bad, just not as good.
I figured I'd try to bi-amp the two together, even though they weren't a match. I let the Hafler run the highs and the Denon ran the lows. This gave the best sound of all. Even though I was listening to the same song for the 7th time in a row, I noticed things I hadn't heard before. I thought there was some sort of interference at that same section with the bass player, but I quickly realized that I was hearing the sound of his fingers sliding up and down the string, like you often hear on acoustical guitar. Although it wasn't louder (I have a sound-level meter), it felt louder.... like the “more presence” impression I mentioned with the Denon earlier, but more so.
In the end, the Hafler is going to continue to run my kitchen speakers (Boston Acoustics CR7's), from the “multi-room” output of the Denon. For some reason the Hafler makes these sound better than the Denon. [Side note – for whoever at Denon thought a variable-volume output setting for the second zone was a good addition, thank you.] Also, when I shut down the Hafler, after a few seconds I get an unholy squeal out of my Klipsch speakers, but I don't really hear much from the kitchen.
Someday, a nice 7-channel amp that I can use to bi-amp my mains and power the remaining speakers sounds like a good idea, if I ever find the $1,700.
