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Well, unless you mean "Tripath" in the generic sense (eg all tissues are Kleenex, all petroleum jelly is Vaseline) the Panny receivers don't use Tripaths at all. They are digital but based on a Texas Instruments module.
It's hard to know which route to go. Every brand/type has its fans. Here's a short list in the order of AC Popularity:
1. Panasonic- The '45 is widely considered the better of the two models, with the '25 being the step-down model. The '45 has a better power supply. The "Party Mode" allows passive biamping with just one unit. The Panny's maintain a totally digital path right to the speakers. Considered very accurate & precise, although a few have called it "cold" sounding.
2. JVC- This one's a newcomer, and debatebly has a Tripath module or something very much like it. This one has something akin to "Party Mode", too, and allows biamping. Decent connectivity if you get the newer model, but the older one lacks component input. JVCs receivers have been described here as "warmer" and more "tubelike", perhaps at the expense of absolute accuracy. Much beloved by Tripath fans.
3. Sony- The Sony's have gotten really mixed reviews here. Some of the cheaper "Dream Systems" have been widely praised by AC'ers, but the concencus doesn't appear too favorable for the ES-2000 and up. Still, the new S-Master Pro module is supposed to maintain a digital signal all the way to output, albeit resampled to 1 bit. I must note at least one ACer has stated the Sony gave him some of the best sound he's ever heard.
4. Harmon Kardon- For whatever reason, no one here seems very enthused with their models. The sound is reportedly not very good, and they're fairly expensive to boot. Caveat emptor...
5. Kenwood- I rank this last only because no one here has yet had the opportunity to hear one. Dmason, our resident Digital Amp Guru, has one on order & hopefully will clue us in as soon as he gets it burned in (although that could take some time- Digital Amps are notorious for requiring very lengthy burning in).
That's it in a nutshell, my rundown of digital receivers. I probably forgot one, but if so someone will chime in.