Anyone listen to Zu Audio's Definition Mk3?

Marc,

You'll need to spend some time on that range of auditions. I missed mention in your earlier posts that your Hovland power amp is the SS Radia and not the EL34 push-pull amp. If you haven't spent serious time with a high-grade SET amp, it would be enough of an adjustment to evaluate one agasint a push-pull tube amps, but in this case you're making the comparison of SET v. a very good SS amp. So give yourself some time to assimilate the differences you'll be hearing, and process what's meaningful to you.

Some things are a one-way street. Since experimenting with SET and SEP amps some years back and settling on a very high grade instance of SET amplification, I am unlikely to ever own a push-pull tube amp again -- especially one of high power output as long as I'm using efficient Zu speakers. Once you've given up the tell-tale crossover grunge in a push-pull amps -- which isn't obvious or so bothersome until you jettison it in SET -- you tend not to want to go back to it but instead pursue better SET. One of the few push-pull tube amps still satisfying for me to listen to is the Quad II monoblock pair, in either restored vintage form or the current Asian reissue, and ther reason is the circuit is about the simplest available in that topology today. You don't mind what it doesn't have, and you appreciate what it does correctly. What you will get from SET at the level of implementation in Audion Golden Dream, Black Shadow and even Silver Night is speed and tonal completeness that you usually have to trade one to get the other at Audion's transparency.

The vast majority of solid state amps are push-pull, but some are Class A, and there are a few single-ended transistor amps, as Nelson Pass is issuing, that present some interesting competitive developments. Lavardin's work in curtailing "memory distortion" in silicon devices yields an unusually musical solid state amp. McIntosh autoformer-output and quad-differential solid state amps are good options for some systems. But none of these options so far, for me, matches the tonal completeness and holistic presentation integrity of very well designed and implemented SET. I'm certainly open to any of them satisfying me in the future.

This is a long way of saying that while the Hovland Radia is a great amp, it might have worked for me back when I was still using low efficiency 2-way or 3-way crossover speakers, but I am down a path I can't return from in terms of being satisfied by that sound again, given what I listen to now. Whether you agree or not will be learned in your auditions. I'll only add that whatever you hear in the Audion amps, can be improved through tube ugrades, but the fundamental amp characteristics are going to be fully present, stock. That said, I'll say the Tenor and Hovland sounds are closer and to me more "correct," than ASR.

The Berning ZOTL is a very clean tube amp, and as I mentioned in an earlier post, it handles event changes with speed and alactrity. It's a good amp. The ZH-230 is a push-pull design, so it has better bass discipline than most SET amps and sounds open and linear, like a wideband push-pull amps should. Good as it is, it sounds tonally incomplete to me -- favoring ultra-definition over holistic presentation. The Audion amps -- especially the silver-content ones -- have the speed but aren't underfed instrumental tone and "correct" human voice. On the other hand, the Berning will sound more like what you've been listening to in your audio past, but with more beauty. The Hovland Radia will have the events, "the consonants and the vowels", in music present but compared to the Audions will sound emotionally bleached. The intellect in music will be illuminated but heart will be more remote. Of all those amps, the only ones that get electric guitar tones truly, authentically right, are the Audions, and Zu speakers are ultra-competent at revealing this. And then once you grok that, you begin hearing the same authenticity in other strings, and in brass, and in voices. Tonally complete is how I think of it.

Buffers are antithetical to system simplicity, so I'm not interested. Get the impedance chain right in the gear you put together. If you buy Audion amps, you will have input level controls, and gain matching will be easy. You have no drive issues if you keep your excellent Hovland pre, or move to Audion. And with those amps, even the TVC will be fine, if that becomes your winning preference.

This is how I see your choices. Others may disagree.

Phil

213,

Are you running your gear straight into the wall with no conditioner?

Also what to you set your components on?

One last question. How do explain the Zu crossover-less design?

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

A bottom line question -

After reading many statements about Zu, Tekton, and other cross overless speaker brands and unsuccessfully bidding on a pair of Essences can I simply put a system together without worrying about all of the detailed issues being discussed?

Can I place Omen Defs in a medium sized (open) family room with a modest 85 watt receiver (or find a used integrated amp like Melody which the Zu people mentioned would work) and a Marantz cd player together and not have to worry about what I am missing? Would I get better sound than from a 1992 pair of Emit Infinitys?

Phil, I really value your thoughts/opinions on all these topics, I think I'm getting a handle on all the decisive factors in going to the next level. The UK Audion dealer demos the Audion SETs thru the Audion Premier valve line stage pre amp, are you familiar with this unit? I see that you personally run your Black Shadow 845s thru a Klimo pre amp, any reasons why no Audion pre? If I go down the SET route, I may keep the Hovland HP200 pre to run things thru, and relegate the Hovland Radia to AV rear channel duties (a bit of a shame since I really love it's sound), unless the Audion Premier or Silvercore/Music First TVCs do it for me. The UK dealer really rates the Silvercore: it's a fantastically put together piece of kit, maybe it could swing you back to the TVC fold if you heard it?
I'm a little suprised to see that even though you run a balanced power transformer in your system, which I do and heartily recommend, you still apply conditioning to the power amp. For years I ran everything thru a Burmester 948 conditioner ($6000+), and despite all the transparency improvements wrought over untreated mains, there was definitely a squeezing of dynamics. Switching to a cheap ($600) 4kV industrial balanced power transformer, all the transparency was maintained with a fantastic increase in dynamic grip; I'll NEVER go back to any conditioning again, and am v. interested in looking at a pro transformer Westwick, 85kg! of copper 8kV isolation. So, you still feel even with balanced isolation to mains you still need conditioning to the power amp?