My experience with the Classe' 70's ( in specific ) are that they are bright and lean sounding. With that in mind, i think that the Tara's would be a relatively good match. If you want something that sounds very fast and clear, try some Nordost. It does not have the mid-bass warmth that the Tara offers. It would therefore lack "prat" in some systems, but it is extremely quick without being "edgy" or "sibilant" sounding.
As to using one channel of each amp without bridging, that is a "bunk" suggestion. Even if it came from the speaker manufacturer himself. Maybe if you had a little "weasel" of an amp with no power supply, but you don't. This was a common trick with the old Quad 405's. It became so common, that Quad even started making the amps with only one channel in the same chassis, but kept the power supply section that was designed for both channels in them. This was their idea of a "monoblock" and it did work much better.
Since the Classe' amps have got good sized supplies in them, i would not worry about that. This is evidenced by their sizable increase in power output as impedance is lowered and their reserve i.e. dynamic headroom rating. Besides that, you are only using them for the mids and treble, where power and current are not as big of a factor. That is, in comparison to if you were trying to power large woofers with a powerful motor structure.
As to Jeff's comments about bridging the amp ( tying the two channels into one bigger channel), voltage is increased and the current remains the same that you would have for one channel. Not only do some amps sound worse when bridged ( primarily due to the use of unmatched driver and output devices from channel to channel ), the bass can get soggier if running full range. If the amplifer actually improves in performance and sonics when bridged, that tells me that the amp was not designed properly to begin with. My guess is that the rail voltages that feed the output devices are too low and the circuit is more comfortable with the higher voltages that bridging produces. Like anything else, output semiconductors and circuits have "sweet spots" where they run best at. Part of building and designing an amp from scratch should take that variable into consideration.
While horizontal bi-amping does have its benefits ( especially if running full range ), i would suggest going vertical in your case. This will isolate the stereo signals and confine each channel to one amp each. This should minimize crosstalk and possibly improve your stereo imaging. If you were running the amps full range i.e. driving the woofers with one channel and mids / highs with the other, i would suggest horizontal.
Keep in mind that there are a LOT of different opinions and variables that apply to every situation. The best way to find out is to experiment for yourself and see what you like best. That way you'll know, see and hear the differences first hand and can chime in with your "experience" and "opinion" as the opportunities arise. Sean
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