Glory,
I live in an area with fairly dirty power. I've investigated a lot of power conditioning and of course, all choices sound different and none so far have been completely positive in their effects. But I haven't by any means auditioned a comprehensive list of candidate conditioners. Currently my sources and preamplification are fed by balanced power/isolation transformers, and my power amps get lightly filtered inductorless AC conditioning. Sometimes I plug the power amps directly into the wall just to remind myself of the difference. I am considering BPT or Furman full balanced power isolation for both whole systems, including amperage capacity for power amps, this year.
My gear in both systems rests on custom made solid maple tables, each identical at 6' long, 23" deep, with total height of 17-3/4". The top surface of these tables is an expanse of lamintated 1-1/2" thick solid maple boards, for 3" total tabletop thickness. The second shelf under neath is solid 1-1/2" thick solid maple boards. The legs are 2-1/2" x 2-1/2" solid maple. The bottom of each leg has a 2" diameter x 2" tall height-adjustable brass cone. The cone points rest on Herbie's Cone Decoupling Gliders (brass receptor/stiff elastomer/teflo). My turntables sit on the top 3" layer, on Aurios Media Bearings. My phono & line preamps, and SUTs also sit on this layer, on Herbie's Grungbuster Dots. My optical disc players sit on the lower 1-1/2" thick shelf on Aurios Media Bearings. I live in a slab house, so this being California, the turntables are great for listening to the planet if I remove the Aurios. Better for music with the Aurios in place. But also, being a slab house, footing is very firm for everything.
Zu crossoverless design: The simple answer is there's no splitter between the power amp outputs and the main driver(s). The more complete answer: There are variances in internal wiring from model to model in Zu's line, but the essentials are all shared. Every Zu speaker is architected around their 10" FRD (Full Range Driver), which some sticklers will insist should be referred to as a "wideband driver" or "widebander." In each Zu speaker, the widebander is handles the frequency range of about 38Hz - 12kHz. In the simple 2-driver speakers, the power amp will "see" the widebander's voice coil directly. In Definition, Omen Def, Dominance, there's a little more going on schematically. But nevertheless, unlike a conventional multi-driver louspeaker incorporating a passive crossover, the amplifier signal is NOT passed through a passive crossover that splits signal before the widebander gets signal. So the power-eating inefficiencies and phase non-linearities, not to mention the tonal colorations and distortions of conventional passive crossovers are not introduced. Instead, a supertweeter is included for top end sparkle and harmonic completeness, and it is rolled in by a gentle passive high-pass filter roughly inverse to the natural acoustic roll-off of the top end response of the widebander. No circuitry enforces the roll-off of the widebander. In Definition and Dominance, which include extended bass performance through built-in powered sub-woofers, input to the sub-amp comes from a fixed low-pass filter that in Def 1 & 2 approxomated its roll-in to complement the natural acoustic roll-off of the widebander's low end response, with an amp level control added. In Def4 and Dominance, this low pass filter is now active and adjustable within specific ranges, for more precise matching of bass performance to a wider range of rooms and placement conditions. The key point is that the main driver -- the FRD or the widebander -- that outputs 90% of the music content that defines your listening experience, is receiving an unfiltered signal that's undisturbed by an intervening crossover. High and low pass filters for frequency extension simply complement the natural roll-offs of the widebander's response.
Phil
