Here are my experiences regarding pairing Harbeth with Accuphase:
- A few years ago I bought a pair of Harbeth 30.2 and I got to hear them in the seller's system comprising an Accuphase DP560 player, Accuphase E270 amplifier, Auditorium cables and a Supra power strip. I was surprised by the refinement of the Harbeth tweeter and the fact that the cymbals were more forward in the mix than I expected (but far from harsh!). The bass of the Accuphase amp was less weighty and muscular compared to my Audio Analog Maestro Anniversary (I had the amp with me and directly compared them), but the sound with the Accuphase amp was more colorful. The seller's system produced one of the best renditions of a string quartet I've ever heard, truly spectacular! He said Accuphase is a very good match to Harbeth.
- Almost 2 years ago I replaced my Audio Analogue with an Accuphase E470. Again, less muscular in the bass, a bit less liquid and slightly narrower soundstage (the AA was a true dual mono design), but much more colorful, better texture, darkish sound overall but with very beautiful, silky and more extended highs (the contrast between the highs and the lower frequencies canvas was better emphasized. as if a degree of midrange bleachness had been removed). It is warmer, more natural sounding, a champion of acoustic instruments timbre rendition. What I also find very special about my current amp is the way it creates a very silent 3D landscape into which you can clearly "see" all the decays and reverberations, I think it's a combination of good detail retrieval with a very low noise floor. I wouldn't call the E470 very neutral, it's a bit dark, sweet and warm but without treble rolloff. Unfortunately the comparison was made on my other speakers, some Martin Logans and Spendors as I had already sold the Harbeths.
- When deciding for an Accuphase I had the chance to directly compare an E370 and the A class E600 on my Spendor SP 2/3R2 and a pair of Sonus Faber Olympica Nova II. The E 600 had better control and separation overall and especially in the bass, which also went deeper iirc, everything seemed better organized, it was clear that it was the technically more accomplished design. Still, I enjoyed the E370 more: the highs were more sparkling, it was more lively and fun, I daresay more musical to my ears.
- I've twice listened to my E470 driving a pair of Harbeth M40.2 Anniversary in a big (5/8 meters?) room that was also very heavily treated with absorption material all over, to the point that the bass was seriously diminished. This is why my impressions regarding the bass should be taken with a grain of salt. Long story short: with my usual cables (only copper, only gold plating, with great midrange texture and color but soft bass) the sound was great except for a rather limp bass. The owner's Parasound A21 power amplifier had definitely stronger, punchier bass but couldn't compare higher up. However, with more synergic cables the Accuphase bass went from "inadequate" to "better than acceptable, quite good already". The rest of the frequency spectrum was exceptional, perhaps with just a bit too forward treble (reminded my of my first experience with this combination, described above - I'd also put it on the weak bass in the room, though, that couldn't balance the treble out) but very smooth with tons of detail / texture and more than made up for the not quite stellar bass. Now, usually the guy who buys Harbeths doesn't do it out of love for punchy bass as much as for their very special midrange and overall balanced and well integrated sound and here the Accuphase serves very very well. So I'd recommend the pairing with the caveat that synergistic cables are a must in order to obtain proper bass. A Synergistic Research Atmosphere level 2 power cable comes to mind.
- Here's an interesting experience I don't quite know what to make up of. I usually don't like skipping the preamp. Both at home and at a dealer I've heard an Accuphase amp used as a power amplifier directly driven by an Accuphase CD player with variable output. In both cases the moderate amount of extra crispness was accompanied by a loss of organic richness and at least in one case by less silk and extension in the highs, so I much preferred the sound with the preamp in the signal path. However, the guy with the M40.2's had an Okto Research Dac with variable output that he used to directly drive the A21 amp. In the Okto / Accuphase pairing, skipping the Accuphase pre resulted in much improved macrodynamics, detail, precision; the time was short so I couldn't A-B the sound too much, perhaps there were some drawbacks that were not immediately apparent but it definitely was an option worth exploring.
Whew! More words than I had originally intended. Hope it helps!