Anyone listen to Zu Audio's Definition Mk3?

Meant Takatsuki notTakasuki.

Phil,
It`s both refreshing and informative reading you contributions to this long but interesting thread. i found your exchanges with glory quite telling, you were coherent,reasoned and mature. You did`nt denirgrate his system as he did yours(he came off as loutish and childish). You gave your honest impression of the ASR Emitter without insulting him or questioning his judgement(it`s always to each their own). I`m glad that`s over.

Your preference for SET amplifiers mirrors my experiences and conclusions. There is no absolute best amplifier, all topologies and genres have some degree of trade offs(no exceptions). What the good SET amps do better(IMO)natural presentation(not canned), tone,harmonics/overtones and simply more convincing realism is most compelling and persuasive for me. SET amplifiers won`t please everyone. Others will be happier with solid state,OTL,class D or what ever.There`re numerous paths to excellent sound.SET just does it better for me.

Regarding balanced AC transformes,I use the BPT-BP 3.5 Signature Plus(over the last 3 years)and I`d give it the highest recommendation. My entire system is plugged into it without any downside, it will only improved your already excellent system.Phil are you familiar with the Takasuki 300b tubes? I replaced my Shuguang BT tubes(very good) with the japanese 300b, it`s a 'stunning' upgrade from an already high level tube.
Best Regards,

Phil, Luxman PD 444 not likely to be on my shopping list, but I'd like your thoughts on the high end tt market. Different designers seem to stress preeminence of one or two engineering principles over all others. So with SME and TW Acustic we have overengineered construction and overspecified motors; with Walker and Bergmann we have airbearing, vacuum hold down and linear tracking tonearms; with Brinkmann, Grand Prix Monaco and Inspire Monarch we have direct drive (latter based on Technics SL1200); with reconditioned Lenco L75 and Garrard 301/401, and Trans Fi we have idler drive (and linear tracking with Trans Fi).
My question is that as a direct drive advocate yourself, together with an ever increasing band of followers, do you feel that direct drive (or idler drive) if implemented correctly will always trump belt drive, or as belt drive advocates argue that it is a synergy of everything being well engineered, speed stability being important but not totally decisive over the whole package (materials, isolation, motor quality)?
Btw, I'll try to get back to Zu considerations on future posts, Marc.

>>I gather you've moved away from belt drive<<

This made me chuckle. Circa 1976 I owned at once a Linn Sondek, Luxman PD444 and a Transcriptor Glass Skeleton. I've been using the Luxman PD441 and 444 turntables for 36 years. In the meantime, Linn, Pink Triangle, VPI, Mission and several other belt drive turntables have come and gone. Along the way I found the Luxman direct drives could be significantly improved by replacing the stock spring/elastromer feet with brass cones on Aurios media bearings. At the time, the Luxman PD444 was the best sounding direct drive turntable of its era, better still than the Technics SP10 and SP25, and it has remained the table to beat in my systems. I have two PD444s with the footing upgrades. So me using direct drive is not a recent thing nor a "move away from belt drive." I used both drive technologies together in my systems over the years, but about ten years ago sold my last belt-drive turntable. I haven't heard anything belt-driven to persuade me to return, save possibly the top version of the VPI Classic.

If Luxman hadn't made the PD44X turntables, I'd probably have been using belt drive all these years. The design choices made for these tables were exceptional and in some respects resemble choice Harry Weisfeld arrived at for his Classic series about 35 years after the Luxmans were engineered. The Luxman PD444 weighs about 65 lbs because its plinth sandwiches a chipboard (better than MDF for resonance control) core between a heavy iron plate and an aluminum top sheet. The drive motor, custom built by Tokyo Electric, includes magnetic repulsion for a "load-free spindle" (really, load reduced bearing), phase-lock loop and a perimeter-mass platter to smooth out any residual "hunting." At a time when an armless Linn Sondek cost $350 in the US, the Luxman PD444 was $895.

The closest equivalent today is the Brinkmann Oasis, and if I were to replace my Luxmans today, that's what I'd buy.

Now, each drive technology sounds different. I did briefly own a Thorens TD124 in 1975. Less was investigated back then about plinthing idler drive turntables in domestic hifi, and idlers had fast lost respect for their problems. But remembering the energetic drive of that Thorens, a couple of years ago I bought a nearly NOS Garrard 401, had a birch-stack plinth made for it and topped it with a Thomas Schick tonearm to use with Ortofon SPU cartridges. That has proved a sufficiently entertaining alternative to the Luxmans that I am pretty sure I'll upgrade it with a slate, slate/wood or solid wood (blocks laminated) plinth. The Luxmans have the more precise, objective sound. The Garrard/Schick/SPU produces a big, robust, bursty sound less extractive of detail than the Luxman, but more imbued with sheer emotion.

I used the direct drive Luxman for 25 years before moving my systems to SET amps about ten years ago, and then to Zu + SET in 2005. So the "shift" between drive systems had different origins. Modern SET + Zu overcame a multi-decades dissatisfaction with hifi for me. The ability to at once be relieved of the incoherence, phase anomalies and dynamic choking of crossover-based speakers and enjoy the absence of crossover grunge in push-pull tube amps, get the tonal completeness and integrity of SET and wideband drivers, with modern sonic accuracy ended the futility intrinsic to high end audio as a pursuit, for me. It was a far bigger development than choosing turntable drive systems. Since placing Zu + Audion SET in my systems, a wider range of music has been made listenable and enjoyable. My patience for truly advancing upgrades is Zen-like. And I am entirely opportunity-focused about improvements rather than chasing irritations around the edges because the central topological problems in speakers and amps weren't solvable.

It's not that I am upgrading via DACs as much as I am going to expand by adding another source, and if I can get an upgrade to optical, terrific. We're clearly, in the waning years of Redbook CD, getting more options for good sound from that format than in all the years of the format's existence up to, say, 2009. So this is worth paying attention to.

When you're evaluating turntables/tonearms/cartridges, beware the many contemporary devices that succeed in making vinyl sound more like CD. Prioritize simplicity and quality of execution. And remember, you have to live with the device day-to-day, which can be different from 2 hours in a store.

Phil

Phil, balanced power really has opened up my system, and in my area we have internet booster stations, industrial power plants etc. which really introduce vast amounts of current/voltage variability and grunge into the local electricity supply. Treating the problem at source with balanced power has been a real eye (ear?) opener, so I am curious to investigate pro studio gear as well, esp. if I stick with the Hovland Radia ss 125w/ch plus rear channel amp. I think that even change to SETs will benefit esp. with any hint of transformer hum etc.
Your upgrading is going down the path of DACs whereas I want to look at a final turntable upgrade, and I am really curious to go down the idler/direct drive route, of which I have chosen a few value for money choices: Trans Fi Salvation idler with linear tracking Terminator T3Pro tonearm ($5000), Inspire Monarch which uses the Technics SL-1200 motor/drive ($7000), and Brinkmann Bardo direct drive ($8000). I gather you've moved away from belt drive. Have you found this as much a paradigm shift as moving over to SET power amps?

I do use an Audion Premier preamp on one of my systems. It is an earlier generation, with full remote control (volume plus switching). The sound of Audion preamps is in the same class as their power amps. The Klimo is in one system as a consequence of once having had Audiopax 88 power amplifiers, for which Audion's preamps did not have enough gain to drive (the Audiopax having only 18 db of gain and unusually low input sensitivity, requiring a preamp of 20 - 25 db gain), and the Klimo brings similar qualities so there was no need to replace it when I replaced the Audiopax with Audion's Black Shadow.

My Black Shadow monoblocks don't consume enough power to be dynamically constrained by light power conditioning. When I had higher-power amplifiers in the past, I did run them straight from the wall but in this case there's no dynamic difference. It's a peculiarity of my present location that mild power conditioning lowers the noise floor a bit whithout dynamic penalty. In another power neighborhood my configuration might be different. I'll likely add balanced power for the power amps and when I do, I am sure I won't be using power conditioning with it.

But I'll make an earlier point again: Balance is my measure, and that includes balance between my interests. My systems are in a good state of equilibrium today. My next push is to prepare for adding hard disk playback by settling on DAC choices that also benefit optical disc playback.

Phil

Obrown,

I am certainly no expert like Phil, but I have 2 pairs of Omen Defs (one with upgrade HO drivers, caps and internal wiring, and one stock pair). I have them in an upstairs loft, 35' x 15' x 8' (the second pair used for surround sound right now). I have taken the non-upgraded pair down into our family room and hooked them up to a 65 watt Yamaha receiver. That room is about 25' x 20' x 9' and opens into a very large kitchen area. The Omens sound very, very good even in the family room with the Yamaha receiver. I find the Zu speakers to be very good in almost any setup (especially the Omen Defs, which are very friendly to solid state equipment) -- I don't think you will have a problem with just plopping them down and getting good sound (much better than a 1992 pair of Infinity speakers -- I used to own the RS3B's).

That being said, I have found that with a little work and persistence, the Omen Defs can sound fabulous. It takes some time fiddling with the gap space under the speaker to the amount of distance between the speakers and toe-in to get the best results, but mine have never sounded bad in any room, in any set-up. I have found they tend to sound better to me with a wider distance between the speakers and more toe-in, compared to other speakers I have owned.

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?

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?

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

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?

David, will do.

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

Hi Phil, once make Def4 purchase I will be auditioning the Audion Silver Knight, Black Shadow, Golden Dream at the UK Audion dealer. This will be fed by the Audion Premier (the only other valve pre likely to be heard other than my Hovland) and Silvercore/Music First TVC preamps, all of these with my complete Hovland HP200 pre/Radia power combination.
I've been so happy with my Hovlands (really upset when they went bust a few years ago), that the Audion gear needs to be a real step up in quality for me to consider parting.
I get the impression from your previous posts that you're a fan of the Hovland sound, and prefer it to the ASI Emitter/Tenor items mentioned.
What would you describe are the major contrasts in sound characteristics between your favoured Audions, my Hovlands, and my likely third and final alternative, the Dave Berning ZOTL pre/30w power?
Finally talking about not being to fully use second half of available volume settings on my pre, and use of attenuators, do you have any opinions on stand alone buffers that vary impedance/gain which source components are connected to, with the buffer then feeding the pre amp, esp Burson Audio AB 160 and Eastern Electric Minimax BBA?
Marc

Andrew,
There have been some major changes in my system. The biggest change has been the Definition IV's over the previous 2's and 213Cobra has eloquently described the differences so I won't elaborate on that further. Regarding SET's vs. Luxman and the TEO cables, I would be more than happy to discuss this with you or anyone else that wants to chat but I don't want to derail the Zu thread. Feel free to email me at dschwegman@gmail.com or call me (404)788-7708. I'm always happy to give my impressions and eager to hear your thoughts.
Lastly, I couldn't agree more with you that a musically satisfying system can be achieved through different approaches. I have been fortunate enough to find happiness through vastly different routes.
David

Good debate/discussion that was handled in a relatively adult manner.

Schw06, I understand that your system has gone through a major overall. Any comments on the relative contributions of your new gear (AMR dac, Luxman amp, Dimitri conditioner) to what you are enjoying now? Any comments on the transition from a SET to the Luxman? What did you think of the TEO cabling in comparison to the Zu?

In my recent experiences with cables and conditioning, you can radically alter the tone and musicality of a system that way. Tubes are often the easy road to achieve this but often seem to lack the vibratory, ambient energy and dynamics of live music even with high efficiency speakers. Just my two cents....

It's hard to argue against any Audion amp to be used with Zu. The Silver Night 300B monoblock power amps are available either as PSET or P-P. 18/18w is fine with Def4. The issue is the bottom end. Look, I have the Golden Dream PSET 300B Audion top-line monoblocks. They are a big step up from Silver Night, with more controlled bass and still, the 845 Black Shadow surpass the Golden Dream on deep bass performance -- and that's after a recap mod to further improve Golden Dream bottom end discipline over stock.

Take your pick based on what's important to you: The 300B PSET amps will have greater ultimate resolution and tone density. The 845 SET amps will have greater drive, more defined and punchy deep bass, and mids/highs will be still meaty, toneful and strong. If you were asking about Superfly, limted to a bottom response of about 30 Hz, I'd say go for the 300B over 845 option. But for Defs, the 845 bottom will underpin a more complete dynamic realism and give you nearly all the midrange magic of 300B SET, with more shove in tonal events and indisputably better dynamic life. If you like maximum presentation of delicate information and don't mind some ripeness in your bass, then by all means choose the 300B PSET. A compromise would be to get more like the 845 bottom end in the 300B push-pull version of Silver Night, but that's at some expense to the holism of SET.

I sometimes use my outstanding Golden Dream pair on my Defs, but by and large, they do tone-drenched duty on my Druids and the 845s put in ceaseless duty pouring watts into Definitions. But if you can, listen to Silver Night 300B vs. Black Shadow, and tell me what you embrace?

I've heard unmistakable advantages to TVCs in place of active preamps on a variety of power amplifiers. On paper, the advantages should be uniform, but in practice they are not. All I can tell you is that I've tried a few high-grade TVCs into Audion power amps. Not even one of those combinations tied with or bested the sound I got from the same Audion amps fed by my extant tube preamps. The combination of TVC + Audion power amp certainly did not sound in any way poor, but compared to other TVC + amp combinations where the resulting sound was a clear improvement, the Audion + TVC combinations failed to satisfy, even sometimes setting sound quality backwards a bit compared to pairing with a fine active tube pre. It's possible that if you rewire the inputs on the Audion power amps to bypass the input potentiometers that the TVC might become preferrable, but then the volume control range and precision may not be adequate, given the high input sensitivity.

You should try it yourself and see which combination you prefer -- no harm will come from disagreeing with me. But if you are asking for my recommendation, my answer is to find best satisfaction, on balance, via Black Shadow over Silver Night, and active tube pre over TVC with Audion power amps, *on Zu Definitions.* If you decide the 300B amp better matches the attributes you value most but you find bass performance the only area of doubt, you can either have a technician perform a recap of the power supplies to improve bass, sacrifice some single-ended tonality in favor of push-pull control, or live with some bass bloat and do your best to tune it out of the Def4 sub via the subs' performance tuning controls. Regardless, these are differences of degree. Any of the Audion amps will be exceptional, and whether to TVC or not to TVC is up to you.

Phil

213Cobra, I've been talking to the Audion distributor in the UK, and he feels the Silver Knight should also be in contention with the Black Shadow. There is an anniversary edition that takes it up to 18w/ch, surely enough for the 103dB eff Def4s.
He's also a definite advocate of using a TVC preamp with the Audion, recommending the Silvercore from Germany.
So is your preference for the Black Shadow (over the Silver Knight/Golden Dream) with the Def4s and decision away from TVC just personal choice, or from a technical standpoint as well?

Nice ending Gary. It was an interesting debate to follow!

I will close this out with I need to get the 4. Something to look forward to.

Good chatting with you 213. At least we agree on the Zu Def2/3/4 as an incredible speaker design and the whole Zu Company being 1st class gents. Would love to hear your setup someday.

I've held out of the fray--but what I can say is my MK4s actually sound palatable with a $600 Onkyo digital integrated. The same combo drove me from the room with Def2s. The reason is the tweeter is more extended, but relaxed--and the mids are cleared up quite a bit by having the new bass driver implementation.

I have a Rives L1 treated room.

KeithR

Glory,
Being the owner of the Def 4's you heard and being the former owner of the actual Def 2's you currently own, I will totally agree with you that the sound coming from them at the party was awful. They were essentially plopped down in the room with 0 hours on the speakers and all of the cabling in the system, an amp with an output transformer dying(I didn't know it at the time), and a turntable with a ground loop hum. We could have inserted the best source ever made and it would have sounded terrible. However, now that placement issues, burn in and complimentary component matching has taken place, I can honestly say the Def 4's are so far superior to the 2's in every way that 213Cobra has described that you won't recognize them as the same speaker in my room if you heard them again. I have owned the 2's, owned the 2's with the nano upgrade (which is a nice step forward in terms of transparency, micro and macrodynamics) and now the 4's and it's not even close. I would take the 4's with home depot lamp cord and radio shack interconnects over the 2's with unobtainium cabling.
I am sorry that you had to hear the 4's under the conditions you did because the sound was truly awful that day but I can say without question the 4 is vastly superior to the 2 once setup properly and burned in (assuming complimentary components).

Glory,

I first heard Tenor amps, pre-Zu and then when I first got Def1.5s, early in the last decade, both their 15w and 75w amps. I have a friend who cycles through high-end gear at whirlybird frequency, including the existing Tenor stereo amp. I haven't heard the $90k monoblocks on Definitions. He brings some of his gear to me because he hears attributes on crossoverless Definitions that he doesn't hear through his Magicos, which is how I heard the current stereo amp. Look, Tenor makes drop-dead gorgeous gear that sounds lovely in isolation.

Now, keep in mind, I have been an OTL advocate in the past. One of the longest continuous amplifier stints in my systems over the past 40 years was held by Futterman OTL monoblocks, hand-built by Julius, which I bought from him directly back in the late 70s. I used those amps for 12 years. So, believe me, when I've listend to Tenor and Atmasphere amps in my Zu-based systems, I *wanted* to like them, and they are certainly quite good in an isolated sense. Both are particularly notable for being "fast" amps that happen to use tubes.

But I have something that changes the context from evaluating Tenor and Atmasphere in isolation, and that is my Audion amplifiers. How expensive does an amp have to be to seem credible to your threshold for "expensive gear?" My Audion Black Shadows are $12,995 per pair and they are the not only the best 845 amps I've heard at *any* price by anyone, they are among the five best amps I've heard, period. But then I have something else: my Audion Golden Dream 300B PSET monoblocks. These amps cost almost $20,000/pr in the configuration I have and can be ordered in configurations up to $36,000/pr. Very few people have them and few here in the US have heard them. But these are the best overall amplifiers I've listened to regardless of price; and yes, used with a speaker with which their power is adequate, I prefer the Audions to Tenor and easily over Atmasphere. They are tonally more complete and musically convincing with Zu Definitions and more so now with Def4. I hear five and six figures amplification more than you probably suspect, and very little of it impresses me. The extreme cost high end in audio generally heads down a resolution vector detached from tonal authenticity, that is unrelated to the way we actually hear music if heard live. This is the central disease of hifi over the last 30 years. Audion's upper tier amplifiers are sonically swift, transparent, dimensionally convincing, dynamic and, best of all, tonally complete.

I don't doubt that you "hear huge sound differences" as you change out gear. Of course you do. The question is entirely whether those huge sound differences are enhancing of or deleterious to convincing musicality in playback. For me, and anyone taking my advice, you are takiing a path that meanders from musical realism *compared to some other options you could take* and which I have taken. But you're convinced of the musical authenticity of the gear you've assembled, so be happy. What does it matter what I think? Regardless, we are talking differences of degree at high cost compared to the gear decision most people have to make.

Generally I've seen very little correlation between most expensive and best, in hifi, so cost doesn't impress me. But best is certainly seldom cheap. We all just decide how much is appropriate. It's not a competition, Glory. Anyone who is attracted to what you describe in cost and sonic consequence, is free to follow. It affects me not at all. I've made no power amplification changes since 2005 in both my systems and I'm only now about to make one preamp change. I bet a lot of people here would like to find that stability in their hifi.

Phil

Marc,

In most rooms, when you get new Def4s, you should start by running the sub Volume control at max (10) and as the driver breaks in, you'll likely back off from that over time. If 10 is too much just dial in what's right. Then starting at about 48Hz for the hinge frequency on the low-pass filter, experiment. You'll find the right handoff in the 38Hz - 50Hz range, and again break-in of the sub driver may nudge a change.

As with Volume, start with the PEQ Gain all the way up and adjust subsequently. For the PEQ Frequency, Zu's suggestion was to start at 31 and work around that centerpoint for the right balance. I agree with that so far, at least nothing about my room or system argues for finding balance around the extremes. Start with 0 Phase shift. You should twirl this to hear its effect and return to 0, listen, and tune from there if you hear advantage. I'd move from 0 conservatively. Doing initial setup through this order of priority, one at a time, will give you a feel for the acoustic interactivity of the controls.

An analyzer can't hurt -- even some of the iPhone analyzer apps can be very helpful if you are not confident of your ability to get it right by ear alone.

My general preference is to put nothing between the pre and power amplification. I have a *very* high bar for processors of any type to get over to justify making an exception. I haven't heard the QOL nor the X-DREI, though know about both. From people who have heard the QOL whom I know, reaction was that it seems successful in restoring tonal completeness to solid state amps, and that it is much less contributive to a high quality tubes sytem. That suggests that something like the ASR, which has come up in this thread, might benefit from QOL, since that amp sounds tonally incomplete to me irrespective of its resolution. That's not-uncommon problem in solid state still, even as silicon amplification has conclusively evolved past its once-common characteristic harshness. In any case, over decades of involvement in this pursuit, one thing is consistent -- processors generally don't last long in systems, so I'm open to hearing and being persuaded, but I am intrinsically skeptical about lasting value. I expect to hear a QOL for the first time in a few weeks.

As for X-DREI, it's intriguing but if you look at their own data, you can see that the processor alters every category of waveform fed into it. So is it a fidelity device or just euphonic? I don't know until I hear it but it has to be transformative to win consideration from me. In both cases you can buy/try/return so if you're game, go for it.

Last, regarding these two devices and anything else like them: Both companies deliberately obscure explanation of how they work. Both do it under pretext of protecting their IP. Well, in the tech game, your basic obligation is to innovate for value and then run faster than everyone who might chase you. As long as both companies refuse to explain what their devices do to the signal and how they do it, demand will be truncated and their impact on the market will be limited. It's their choice. At least with the Stein Harmonizer H2, the developer says flatly that his device relaxes the acoustic "stiffness" of air. He doesn't explain how, but he's not putting his device in my signal path either. If you're passing my system's signal, tell me exactly what you're doing with/to it.

Phil

213,

I heard the Def4 set up by Zu at a Zu party in Atlanta with all Zu wire and what I would call OK gear. Not very good results. Even installed my Lampizator Dac into the system and it didn't even begin to help the sound coming out of the 4. My 2,which was the Def4 pervious owner, far outran the sound coming from his system. The 4 will not out do a 2 with Ford Focus gear and I heard that to be true. My friend was there and when we got back to FL and heard my 2 he was in stitches with laughter as the 2 was so much better.

I find it very hard to believe you heard Atma/ Tenor amps on your Def and that they moved you away.......what Tenor amp did you hear?

You are a good salesman but you are not going to convince those of us that hear huge sound differences when upgrading to, yes more expensive gear.

You can try and explain this away but what we heard will not be forgotten.

Phil, if I knew when to quit, I would have put my wallet away when I paid c$15000 for my first high end system in 1996, and not gone on to spend another c$85000 with never ending upgrades (Zu Def4s pending)! Ha ha!
You're right re prev post, I just wanted to know if control settings were intuitive to get right one at a time esp if they interacted with other settings.
I do know another (non Zu) listener who has an outboard active amp for his bass module with v.similar controls who uses dsp shaping (behringer?) to get correct levels for his room, and wondered if this at all is a route to go down with the Def4s.
Have pretty much settled on the Gloss Black finish, may go from never ending sub bass adjusting to never ending spkr polishing!
I really value your no-nonsense attitude to combining engineering principles and listening experience in your final opinions-can you peruse a couple of items that fit between pre and pow amp and tell me what you think?
First is BSGT QOL, second is NEUTRALAUDIO X-DREI. Both have threads on A'gon in Amps forum.
Marc

Spirit,

I answered this question in a previous post. The five sub controls are interactive primarily insofar as the outcomes of anyone one control's settings acoustically may (likely will) influence your preferences on some of the others. If you change the hinge frequency, you may want or need some adjustment to the PEQ or the level, or both, for example. The phase setting may be more benign to other preferences but even that can influence level, PEQ and hinge preferences. What I wrote in my prior answer was that I do not see the five tuning options as being unnecessary complicated nor preventative of finding appropriate bass performance reasonably quickly. The new control options are not so simple as having only one level knob, but are far less tweak-inducing than a full spectrum parametric EQ and X-over combination. I think Def4 is pretty easy to dial in, and the controls are sufficiently intuitive to be usable by both experienced and novice owners. The primary enabling or inhibiting factor is the user's awareness of what to listen for, or whether they have either an intuitive or finely-honed sense of what sounds "right." Unless, that is, you're measuring, have the gear, and understand what's actionable in the resulting analysis. Not to mention, how obsessive are you -- do you know when to quit?

Phil

213Cobra, and other users of the Def4s, can you fill me in a little on the 5 way sub bass adjustments on the back of the speakers. This obviously differs re the solitary volume control on the back of the Def2s.
What I would like to know is if each control is independent of the next, or whether adjusting one parameter affects the previous/next setting. If each setting affects previous/next settings, then there is a whole lot of never ending tweaking to be done. Or is each dial adjusted and set with an apparent correct setting for the spkr/room interaction for that dial, and no influence on others?

Glory,

>>Musical to you may not be musical to me but there is no way with the system you have built around the Def4 you can get better results than I have with my Def2.<<

You're welcome to that opinion. If you have a Def2 system, it's going to be pretty good even with the gear you've chosen. I'll only say I'd rather have listened to my own Def2 system, and more so still with the further upgrade to Def4.

>>Moral of the story is one must build, from the wall out, with SOTA gear to hear the Def speakers at their best. Having so so gear on a Def4 will not make it sound better than a Def2 with Nano drivers that has from the wall out HE gear.<<

I suppose that's the "moral" to *your* story. Who agrees on what's state-of-the-art? And what's the correlation to cost? And then what's the correlation to convincing musial realism in domestic reproduction? For as long as I've been involved in this interest, I've found the three quite weakly correlated, no less so today. I'll say that over 90% of all sound represented as "high-end" to me has instead impressed me as musically and aurally dysfunctional. Have you heard Def4? I'm guessing not. There are *many* combinations of gear absolutists won't consider "SoTA" that with Def4 will produce greater musical realism than Def2 -- even with HO or nano drivers -- such are the advances in total system performance. This is the paradoz of Def4: it is more revealing, more transparent, more dynamic and yet even mediocre CDs and LPs sound better in every respect than on Def2. You only hear in contrast how much Def2 you hear with that speaker in a system, compared to the marked and further neutrality of Def4. I think you will grasp this when you eventually upgrade. Until then, you're selling conjecture.

Also, a prior post hasn't made it to daylight. I mention in it that it's been years since I've used an NAD M55. In any case I make all my serious judgments from analog.

Anyway, we disagree. I have my path; you have yours.

Phil

Sorry 213 but each amp I moved from had a reason other than dissatisfaction. The OTL amps were head and shoulders above the noisy/colored sound of the SET amps I had. Heat from the Tenor amps drove them out of my FL. Home.

Musical to you may not be musical to me but there is no way with the system you have built around the Def4 you can get better results than I have with my Def2. It takes T&E and $$$ and lots of wisdom to build a musical connecting system. I wish it were that easy to P&P Zu speakers in a Ford Focus system and get HE results.

Moral of the story is one must build, from the wall out, with SOTA gear to hear the Def speakers at their best. Having so so gear on a Def4 will not make it sound better than a Def2 with Nano drivers that has from the wall out HE gear.

Enjoy your system as I do mine.

Over and out.

Agear,

A system is always holistic, else it's not a system. I don't think anyone -- and certainly I don't -- changes or adds compenents without adjusting the context.

When I listened to ASR in my system, I used all-copper cables first; reverted to silver-content for reference, but I had no expectation that silver would be the right context for an ASR amp. I listened with eight different phono cartridges on three turntables with five tonearms. And I listened to a variety of digital sources. But none of that mitigated the basic character of the ASR, which was undesirable to me.

The interactions that affect perception of ss gear aren't any more numerous nor fewer than those that affect perception of tube gear. Glory chose an amplification migration that I'd find unsuitable or more to the point, drifting *away* from convincing music presentation. I'll also note that every step along the way Glory contended in these forums that each amp was his destination, only to become further dissatisfied. If that happens with the ASR, what then? The trial and restlessness is often the indicator that the path is wrong. But if Glory is happy with his ASR, his cable choices and his Zu based system overall, I have no quarrel with that. It's his to enjoy on terms he sets for himself.

Phil

Phil, Glory's sonic evolution was predicated on his system in its entirety. If our analysis is not holistic in that sense, we miss the boat. The ASR is ruthless, so silver wire, source, and other variables potentially color one's perception of it more so than tube gear. Plain and simple.

agear,

Migrating from Audionote to Atmasphere to Tenor to ASR isn't a direction I'd take, and I've heard all of it. So I don't know how anyone would judge that or any other system as " the most musically convincing system to date." Well anyway not for me.

I did listen to ASR in my system. Even had a chance to buy it at half price. It didn't earn a spot, simple as that. If someone asks my advice ASR isn't going to be on a short list from me, but if someone else likes it, it's their call. I'm unswayed.

Phil

Spirit, Clayton Shaw is clever and his spatial systems are worth considering particularly if your speakers use a digital xover. The Black Hole concept is not new. Nelson Pass and others have attempted similar manipulations in the past (http://www.stereophile.com/content/phantom-acoustics-shadow-active-low-frequency-acoustic-control-page-2)

Cobra, it looks like you have done your homework to a degree. I am not surprised that you have silver wire in your rig. Most SET owners seem to navigate towards silver. Like Glory, I wonder about your source. Did you demo the ASR or was it in someone else's system?

I know Glory has evolved from Audio Note SETs to Atma-sphere OTLs to Tenor OTLs and now to the ASR Emitter I exclusive. He has the most musically convincing system to date. Go figure....

Spirit,

You're right, the Black Hole is effective if the problem you have is the one it solves. Since you already own one, you conclude it's still valuable to your system when you move to Def4. And at $1250 it is an affordable antidote to a vexing sound problem in some rooms.

Gloss finishes on Zu speakers come at a premium, so the maximum performance per dollar point is obtained with one of the stock matte finishes. If you have a rambunctious family, the matte finishes will be more maintainable. If your environment is serene, the gloss finishes seriously raise the perceived value of the speakers. You might look into ebay and Audiogon history for some data mining to see if there are patterns in value retention different for matte or gloss. I don't know. I have a 60" final gen Pioneer Elite Kuro between my Defs in gloss and distractions during movie watching aren't a problem for us. I can't say with a larger image cast by a projector. But it you are wary of visual distractions from gloss reflections, consider getting your hardware anodized black. Silver FRD rings and the big supertweeter lens are more noticeable than reflections, in HT. IMO, among the mattes, Cosmic Carbon looks more suited to the value of the speaker than absolute flat black, in a domestic setting. But if HT is your prime concern, matte black with black metal hardware, will vanish visually in the dark.

Phil

One final thought for 231,

The NAD M55 Master Series source is not going to get the job done with the Def2/3/4 speakers for max output of their potential. I am sure you have good sound but a 4 cylinder car will not perform like a 8/12 cylinder HP sports car. Ford Focus at best.

If your goal is OK good sound then you have that but the Def speakers will respond much better with a higher front end source. The Def speakers are not a miracle working speaker. No wonder your believe what you do about wire. You will not hear a wire change if the source is not up to snuff.

213Cobra, I am v.sure that the Def4s with more even room loading will mean less reliance on the Black Hole, but it has been SO beneficial to revealing the Def2s performance envelope that the move to Def 4s is less of an overall necessity, but a v. nice choice to have. I would really recommend it to all Def2 owners because of the bass management issues I'm sure we all have in all types of rooms. And all for just $1250 more.
My main dilemma (are you reading, dear girlfriend!) is whether to go for Cosmic Carbon (light speckled grey which varies appearance in different ambient light situations), True Matte Black, which like it says on the tin, is totally light absorbent, or Gloss Black, which is so drop dead gorgeous, but I'm really unsure how watching a film from a PJ onto an 88" wide screen directly btwn the spkrs will distract with reflections.

231 writes,

It's more important to preserved Zu's B3 all the way to the amp than it is to futz with alternate cables, for getting the most out of Def4.

Did that and you are wrong! Your writings will appeal to the budget minded Zu owners but for those who are wanting the best sound out of our Zu speakers we will trash your thoughts.

Your ideas on gear and P&P reminds me of a person owning a high $$$ sports car that can not take his car on the race track but has been limited to driving on city roads in a 45 MPH zone. Your noisy 845/211/300b will do 0/60 in 10 seconds and take turns like my old '65 Mustang. Have at it if you will but I want my Def2 on the race track and not just do city driving.

Gear/room means everything from the wall to the room where your  speakers are placed. Your speakers are only telling you how you have done on building the rest of your system.

Truth is not found in  huge amounts of written words on paper with ideas that are one's opinions. Truth is in the hearing and your take on wire is not what I heard to be true by a long shot in my system.

Have fun with your city driving LoL.

Agear,

You wrote "Zus are not impervious to associated gear." That's certainly correct and if anything I wrote was inferred by others to mean otherwise, I certainly didn't intend it. I've lost count of all the cables types I've heard on my Zu systems over the past seven years I've owned Zu speakers, let alone all the cables I've ever heard. But I'll mention a few that bracket the discussion: JPS Aluminata, Audience, 47 Labs OTA, Kimber, Audioquest Everest, Zu Variel, Ibis, Event, Mission. For the moment, let's stick to speaker cables.

I'll also add that I have heard an ASR amp on Definition 2, and while I understand why that brand's amplification is well regarded, it's not an amp I consider musically convincing. It has a lower noise floor than top tier 845 SET amps, though my Audion amps aren't noisier enough that their noise floor is obscuring to the point of allowing the ASR to reveal anything I can't hear via the tube amps for that reason. The ASR is a "better microscope" than the 845, but not a better microscope than my Audion Golden Dream PSET with its high silver content, including in the OTs. Certainly it's possible that a given listener prefers something akin to the ASR amplification over what I listen to, and certainly the complementary or compensatory properties I would want from cable would be affected by the amp I listen to. When I want to hear cable contributions, I aurally dissect using the Golden Dream amps first.

In the compass points of cable in the examples I've mentioned above, there are several design approaches. JPS prioritizes noise elimination and shielding through brute force material density and mass. Audience emphasizes time domain. 47 Labs emphasizes coherence and speed. Kimber emphasizes RF rejection and magnetic behaviors. Audioquest strives for transparency. Zu seeks coherence and balance. Auditorium targets convincing tonality.

Some of these cable choices are mass-intensive. Others eschew mass every way they can. There's a long-running debate about the sonic benefits of very low mass connectors vs. metal-intensive termination. So in brief terms, JPS Aluminata is quiet and good at preserving and presenting dimension, but I don't have significant cable-induced noise, so everything is pretty quiet anyway. I did not find any collapse of dimensioning going from JPS to Zu Ibis, but I did find the JPS to be less dynamic, certainly smooth but not as fast as Ibis. More to the point, it wasn't as coherent and resolving as the 47 Labs OTA, which counterintuitively uses single-strand conductors. But I can understand how the JPS can be heard as fleshing out a leaner audio device chain. Of the cables I mentioned, the various Audioquests had no advantage over anything else, so set all AQ aside for this discussion. Auditorium 23 cables are the most reliably musical regardless of source material of this group. Kimber never makes a misstep but it doesn't equal the best of the group in tone, transparency, resolution or dimensioning. It's a safe choice. Audience is incisive and precise. Zu delivers total balance with the silver content cables matching anyone's resolution. In some significant properties of sheer musicality, I liked Auditorium and 47 Labs best, and both emphasize low mass, particularly at termination. I would take either over JPS. I came back to Zu Ibis (and I can equally endorse Event, which is actually more forgiving than Ibis) for its well-rounded ability to be exceptional on speed, bursty dynamics, tonal coherence and event coherence.

I've tried many more cables than this, including Cardas and Nordost, and I haven't even gotten into ICs and power cords. But there's another dimension to the discussion. How much money should be allocated to cables in a system, or how much is needed for the system to be musically convincing?

All of the speaker cables I mention above were quite good on Definitions, in varying ways. None made the system unpleasant to listen to. But with a cable as good as Ibis or Event, I can drive larger positive deltas in musical performance by upgrading elsewhere with the thousands of dollars not spent on cable if Zu, Auditorium and 47 Labs are chosen instead of JPS Aluminata or the upper line AQs, for example. And if you prefer the more moderate cost lines, then standing pat on cables to put money into other areas or just buy more music, or pursue another interest in life can be the better choice. I can spend $6000 on speaker cables, but I won't if the results aren't compelling. I haven't heard compelling from JPS, as an example. I've heard "good" that didn't win against alternatives. But someone else like Glory who may hear differently or whom has different criteria for being convinced of a system's musical thruthfulness might prioritize his resources differently.

But I repeat that with Def4 restoring the Speakon connector for B3 geometry pass-through to the amp, the benefits of leveraging that via a Zu cable are significant and not exactly matched by other good cables that can't continue B3 to the amp output terminals.

Phil

Phil, what other wire have you demoed in your system? In audio, hearing is believing. I know Glory has performed extensive experiments with wire, conditioning, amplification, and sources in addition to hearing other Zu based systems, and his experience has been consistent: the Zus are not impervious to associated gear. System resolution may also play a role in discerning wire changes. There is a significant differrence between a set of 845 monos and an ASR in terms of noise floor. The ASR is a better microscope.

Your comments about rooms are spot on IMO. Overdamped and synthetic sounding is the norm. Older homes with vaulted, parabolic ceilings and certain concert halls do a better job propagating ambient energy.

Some interesting assertions here:

>>SET amps are good for what they do but there are other amps that from top to bottom will out run them. <<

Bring me one.

There are a LOT of SET amp choices but they aren't all equally good. You don't have to go all the way to an Audio Note Ongaku. Until you specifically hear an Audion silver content Black Shadow (845 SET) or Golden Dream (300B PSET) monoblock pair on Defintion 4, you won't know whether anything allegedly SOTA can meet or exceed it. People who have heard this next to ARC REF seris, Dartzheel, Nagra, etc. who prefer the Audion aren't compromising for SET. So, sure, at any given point of time maybe there's something new that beats a stellar SET amp on a Zu crossoverless speaker. Could be. But no push-pull tube amp at any price has shown me ability to hide its crossover grunge. No SS amp at any price has shown the holistic tone of highly developed SET. But I'm open to the discovery.

>>I have found a huge upgrade in Footers by Equarack/Stillpoint Ultra under the Def2 that transforms the sound of the speaker.<<

Definitely easy to accept. Foundations are inflential on resonance management. The effects are specifically unpredictable dependent on other system, room and resting surface factors but it's certainly worth investigation to determine the right upgrade for your environment.

>>...but if you have the Def2 with the new Nano drivers and SOTA gear you just might have better tunes than the Def4 owners with lesser gear.<<

Look, I'm the last person to push people into premature upgrades or to encourage upgrades beyond an individual's ability to spend. Def2 by any measure remains an excellent speaker and plenty of people with more expensive but less capable speakers today would be thrilled with it, along with people who can suddenly buy Definition architecture on the used market at an accessible price.

But until you hear how large the improvements are in Def4 over Def2, the sentiment that Def2 with state-of-the-art gear and a nano-drivers upgrade will be "better" than Def4 with lesser gear, is uninformed conjecture. At some level of comparison, sure. But consider that I and others have noted that CDs are more listenable and enjoyable on Def4 than on Def2, despite Def4 being more revealing in every way, and you can see that the listenability quotient applies as well to modest amps, modest sources, modest cables, modest analog. The smooth extension and spatial openness of the supertweeter plus the surprisingly upgraded bass definition, discipline, room loading and clarity have profound effects on your perception of imaging, midrange performance and tonal engagement.

Somewhere in the mix of SOTA gear on Def2s vs more modest gear in Def4 the proposition might become tenable, and certainly in past Zu speakers I'd have agreed. The equalization in performance between fab gear in Def2 v. acceptable gear in Def4 isn't the slam-dunk given you'd imagine, IMO, which I illustrated to myself a couple of weeks ago. My Quad II push-pull amps designed in 1951 sound on my Def4s superior to my 4X the cost 845 silver content SET amps driving Def2s, but the same 845 SET amps on Def4s blow away all comers thus far and the Quads, good as they are, can't compete.

If you have Def2s and need to stick with them for the forseeable future, be confident you still have a genre-defining speaker that can satisfy you for years to come, especially with Zu's willingness to sell you nano drivers to install in them. Just don't listen to a Def4 until you're prepared to buy them. Or send your Def2s back to become Def3s, to get yourself halfwat way there.

Phil

No doubt the Spatial Black Hole has its benefits, and I know it can mitigate acoustic anomalies in very troublesome rooms, which it sounds like you, Spirit, have had to cope with. That was a good suggestion Sean offered.

But before the wider audience begins to think this sort of thing is necessary -- yet another box -- two things are worth keeping in mind. First, in decades of listening to both live and recorded music, I've yet to hear any of it in an acoustically perfect room. And when I've heard a "perfect room" like an anechoic chamber, treated-to-the-hilt listening room, or an engineered recording studio, it didn't sound much like music the way it's actually experienced, though the sound might have been beguiling for reasons other than realism. On the other hand I've heard two rooms that were perfectly convincing for listening to music, and neither were free of anomalies, including audible nodes and standing waves.

The two best "rooms" I've ever heard were 1/ Symphony Hall in Boston. I had a share of season tickets for 10 years when I lived there. It ain't perfect, but it's exceedingly natural, involving and satisfying to hear music performed there. The second "musically perfect" room I've heard was a family room on the first floor of a large Victorian house on the shores of Spy Pond in Arlington, Massachusetts. It wasn't a house I lived in. It happened to be dimensioned to nearly the same proportions as Symphony Hall. Otherwise it was just an untreated family room with normal furnishings, and a combination of large glass windows on two walls, a large fireplace on one long wall, and a shortwall of in-build bookshelves and cabinetry. The thing about that room was "any* combination of gear sounded not merely good but sensational in it. A receiver with a pair of $400 speakers sounded like $30,000 worth of gear, regardless of audible nodes. A friend owned the house and we made a project out of trying to make the room sound bad by installing the most objectionable hifi gear would could find. No avail. Throw it your worst -- that room made everything sound golden.

If you have a dedicated listening room and you want to hone it, have at it. Yup, the room is the big number in the equation of hi-fi. The Black Hole is a one-trick pony tackling a sliver of the problem. But then go out to listen to live music, and think about what you hear, how hearing it in compromised space isn't eliminating your enjoyment, and then go back and question whether your hifi optimization might be creating a more synthetic sound than you intended. Maybe, maybe not.

Agreed, it's absolutely true that sorting out the lowest octave's affects in your room has disproportionate benefits, and the Black Hole may be just the ticket if you have space for it or otherwise are willing to live with its presence. But if you don't have space or aren't willing to accommodate it for whatever reason, and you upgrade to Def4, you will find that the newer speaker excites the room much less, more evenly loads the room with its bass output, and generally reduces unfavorable room/speaker interaction. My moderate bass piling at high SPLs with Def2 is tamed and virtually eliminated with Def4.

The sub-bass user controls are not so simple as Def2's single level control but not so bewilderingly interactive as to cause endless twiddling. The tunability is logical and manageable, IMO. The sub driver is pretty stiff when new, so Sean gave me notice it will take some time to play in. Whereas Def2's level control offered equal gain boost and cut, with most people on setup starting with the sub level control at its midpoint -- 12 o'clock -- and then backing off a bit to perhaps 11 o'clock or boosting a bit to perhaps 1 o'clock, the expectation with Def4 is that cut is the more likely scenario, so in most rooms taking in brand new Def4s, you'll start out with the level control at 9 or 10 and back it off as the driver plays in and becomes more efficient. So I'm still at that beginning stage for level and it's spot-on. The low pass filter hinge frequency is set at 45Hz, the PEQ at 31Hz, and phase is set at 0 shift. I have no complaints but I expect to tweak these settings as the 12" driver plays in and limbers up.

Despite Def4's truly full range, I have the fewest resonance anomalies of any speaker I've heard in the room, and that includes well above the bass range too. So whatever problems you might have now with Def2 are going to be mitigated by Def4, *possibly* to the point of irrelevance.

Last, I dug further in the cabinet differences between Def2 and Def4. The front baffle is immensely stronger on Def4 than Def2, both because the further-apart spacing of the FRDs leaves more material in place at the juncture of three drivers, and (more important) the large compression tweeter and its lens form a stressed, compressing, rigid member that seriously boosts the rigidity of the front baffle at what would normally be its weakest area in an FRD-T-FRD arrangement. This is a major factor in further reducing front baffle talk from the levels reached in Def2 compared to Def1.5. Then, what you can't see is that to further drain the FRD's frame-radiated energy away from the baffle into the interior of the superstructure, each FRD's isolation chamber has an interior front-to-rear taper formed by interior side plates that are cleated into the front/side panels' mitre join, and angled inward by 15 degrees, then fastened into the rear panel. This nearly eliminates side panel talk highly evident in Def1.5 and much attenuated in Def2, plus drains the FRD energy into the rest of the cabinet where it is then steeply damped by the rigid aluminum plinth that bears the rest of the mass of the speaker.

Phil

It's more important to preserved Zu's B3 all the way to the amp than it is to futz with alternate cables, for getting the most out of Def4. This is the thing that All Def2 owners as well as Zu owners who have owned only their speakers during the "B3 Speakon interruption" -- you don't know what was left untapped when B3 was taken away. Even on the less resolving Druid, this is apparent if you have an early pair incorporating the Speakon interface, and upgraded over time to v4 status. You can clearly hear gains from exotic and even inappropriately expensive speaker cables, but when I then run B3 all the way from driver back to the amp outputs, rightness sets in.

So anyone enamored of cable differences and wanting to spend money on that path, knock yourself out. Cables do sound different, though landing on "better" is a crapshoot. Most are not improvements, occasionally one may be. The best non-Zu speaker cable I've heard so far is the Auditorium 23.

In ICs, if you're getting a flat 2D sound because you've substituted Verial for Teo, something else is likely wrong or there's something about the parametric qualities of the other cable that your listening mind interprets as dimensional. If the latter is the case, fine -- no one can argue with that. But it's far from generalizable that Zu Mission or Event ICs or speaker cables (or the older Verial/Ibis) are not capable of conveying the depth dimension information.

Still, cables are the least urgent thing to get right of all the variables you can pay attention to, but any given individual might prioritize a cable change benefit they hear, ahead of something else that to others makes a larger difference. This pursuit offers more ways to spend your money than most people have money, so if cables are your drug, go with it.

However, one of the best benefits of Zu speakers in all their architectural variants is their ability to be adapted widely and to yield excellent and convincing music fidelity with much less than state-of-the-art gear, and with fairly casual set-up. In fact this is elemental to the Zu brand. They want you to obsess less. They want to deliver exceptional value so you can spend less money on gear and more on music. They want you to be able to leverage ultra-fi gear but not mandate it you must spring for it. Just as Omen Def or Superfly can clearly leverage the benefits of associated amps, preamps and sources far above their price, Def4 can deliver its prodigious sonic presence when lashed to modest associated gear and still sound beautiful. My *advice* for how someone allocates their resources across gear categories will vary according to a buyer's goals, and it usually won't be to mate Defs with a cheap amp, but there are exceptions.

Additionally, while Zu does nothing to prevent the typical audiophile obsessions, they don't encourage them either. Like me, if they ran the world, their speakers wouldn't be hidden in dedicated listening rooms and man-caves -- they'd be out in the living areas of the houses of their owners, to be heard and seen in everyday living. So while a portion of the market buys Zu and installs their speakers and cables in systems located in dedicated audiophile rooms, Sean designs for the buyer who will install them in a living room where there's just one logical place for speakers, from a utility perspective for the way the room is used, and that setup is going to sound good too. Level 'em; get the toe-in right; you're good. In the true-fidelity speakers market, Zu is the "PnP" -- in speaker terms the Plop and Play" -- solution that also happens to reward obsessives and tweakers who are inclined to nth degree optimization.

Phil

213 writes

Cables are the least urgent thing to get right.

As much as I love to read his thoughts I do believe the wires made by Zu is not going to bring out the very best in the Def2 or 3/4. I have the Verial IC and installing it in place of my Teo is a flat 2D sound that must be removed after a short listening session. Same for the Event SC. I do believe for the $$$ it is killer wire and think if you have it you have not been taken by the $$$ wire game. I do believe that you are missing a lot if you stick with said wire.

JPS Aluminata also will unleash the glory of the Def speakers.

213Cobra, will definitely try those attenuators. Now can I offer a little advice to you: please try the SpatialComputer Black Hole anti-standing wave device. All I'll say it has totally transformed the way my Def2s sound, by removing bass humps in the room (I have a node of 27.1Hz in my room), so much so that I often pop around to the back of the 2s to see if the bass is still pumping out (of course, it is). Sorting out the lowest octave has allowed bass definition (eg kick drum/plucked bass strings), midrange intelligibility and treble extension to improve, causing a real increase in transparency and soundstage. My guess is I'm experiencing a lot of what the improved bass in the Def4s is going to give me.
When I get the 4s, I'm going to investigate the possibility of more units to help at least a further 3dB (unless bass loading of the 4s really presents no issue).
My listening space is 22' wide x 27' deep x 13' high, to one half of the 22' width, a v.live industrial loft type space.
Re the Def4s, how are you getting on with the 5 way user controls on the back of the speakers? I know someone with open baffle spkrs whose active bass module has similar adjustments and he has relied on Behringer dsp shaping to maximise sound. Are Def4 owners likely to need dsp for the bass adjustments? My question is that do you settle on one setting at a time (from default), each setting independent of the next? If each setting DOES affect the next, surely there will be just too many combinations to try.

I've been a Zu owner for the past 6 years going from Presence to Def2 with the new Nano drivers.

With all due respect for Zu as a speaker builder I have found AC/IC/SC from other brands have brought my speakers to their max.

SET amps are good for what they do but there are other amps that from top to bottom will out run them.

Having SOTA gear from power/source/amp/wire to speaker will unleash the Def speakers to their full potential. I see some Zu owners just plop down their speaker on the stock points. I have found a huge upgrade in Footers by Equarack/Stillpoint Ultra under the Def2 that transforms the sound of the speaker.

You can kick my butt, but the 845 amp with some OK wire and OK power on the Def4 will not keep up with Def2 with the new drivers and SOTA gear.

There is no other speaker in my sights than the Def4 for the future but if you have the Def2 with the new Nano drivers and SOTA gear you just might have better tunes than the Def4 owners with lesser gear.

It's always helpful to have more of your volume control's range be useful and accessible than less, if all other things are equal. But would you be happy with a preamp you like less just to get more useful range from your preamp's volume control? Unless the useful rotational range is very small, probably the answer is no. You have two feasible choices if you like your power amp:

1/ Get a lower-gain preamp if you can find one you like as much;

2/ or more feasibly, get a pair of Rothwell RCA inline attenuators (review: http://www.enjoythemusic.com/magazine/equipment/0803/rothwell.htm) These can be placed in-line between your preamp and power amp, to scrub off 10db of gain before the audio signal hits the power amp inputs. If you look around, you can also find similar attenuators at 12db and 15db reduction. Simple, effective, cheap and you get more useable twist in your volume control. Don't obsess about having another resistor in your signal chain.

You could also get a TVC from Music First (expensive) or DIYhifisupply.com (affordable), for attenuation without gain.

I do hear the Berning as tonally leaner (a little too lean) than the Audion Black Shadow 845 SET. Audion electronics are uniquely fast among tube gear but fully fleshed tonally, so I don't agree that the Berning has more apparent speed than the Audion. The Berning sounds "faster" than the majority of SET amps outside of Audion particularly, and some Sophia. I have to extrapolate that Melody qualifies too. Others might. Audion's 2a3 and 300B amps are also impressive like the two top line amps that have silver content, for their quickness, so it's not just a top-line exlusive for them.

You can tune the Audion 845 SET nicely to preferences for warmth and tone or objectivity, via the 845 tube selection. The 845A, B, C, T, KR Audio, and NOS RCA/United/GE tubes lend the amp different voicings. With the Berning, your locked.

As for the Def4 cab structure vs. Def2: I haven't yet seen a drawing of the interior of 4, to see the actual strucure improvements beyond the obvious, but the obvious things are very significant. First, the speaker no longer has 4 ten inch holes cut out of its rear panel, where Def2 had 4 sub drivers. That by itself strengthens the tower box. Internal damping has been upgraded and I believe there is more corner and junction bracing. But the other obvious change is the speaker tower's foundation. The stronger box no longer compromised by cut-outs in the back panel is now firmly bolted to a 1-1/2" thick machined aluminum plinth that is vented for sound to escape and serves as mounting for the 12" downfiring sub. It's a robust, very stiff physical foundation for the more rigid box to rest upon.

I surmise the front panel is now marginally stiffer in addition to being damped by the considerable mass mounted to it. The baffle should be a little stronger in the upper half of the cabinet because the size of the Radian supertweeter forces the FRDs to be mounted further apart than on prior Definitions, reducing how much structural mass is lost in a concentrated area on Def 1 & 2 where the FRDs slightly overlap the supertweeter cut. But the big progress on reducing cabinet talk was between Def 1.5 >> Def2, with the upgrade to 15 ply voidless birch from MDF. That difference for intrusive cabinet resonances was dramatic.

Phil

Wow, after reading this entire thread I am ridiculously tempted to get the MKIVs.

I currently have the MKIIs + Tom Evans Linear A + PS Audio Perfectwave DAC (all my music is digital flac). Very happy with the combo but would love to hear the MKIVs. Probably will have to wait until they hit the used market before I can afford them though.

To all those who got their pair, enjoy!

213Cobra, you come to the rescue of us poor, non-technical souls out here! I do love the sound of my Def2s thru the Hovland combination, and if this is continued into the Def4s I won't be in a hurry to switch amps. Handy really, since giving my cash to Zu won't allow me to for the time being anyway!
So I gather from your answer, if I'm not mistaken, is that I don't have to chase possibility of using full range of preamp's volume control to acquire more dynamic control over sound if I'm happy with sound with preamp never beyond half way up as it is anyway.
Reading between the lines, the Berning amp combination, to your ears, is leaner tonally and faster dynamically than the Audion 845 SET, and the latter is where your musical happiness lies. That is warmth and tonality win over detail and speed, given the choice between highlights in these amps' signature attributes.
Luckily in the UK I'll be able to get a home demo of Audion Black Shadow and matching pre, and Berning pre/pow combination to make a clearer decision (if ever get to that stage).
Just getting back to the Def4s, since this thread is about them, can you go into any discussion re their stiffer structure: I gather quite a bit more metalwork has been applied esp. in the plinth for the sub bass and also the front panel for the FRD's/supertweeter which has increased weight 50% and contributes a lot to controlling cabinet resonances.

The Berning 30/30w ZOTL amp has a push-pull output topology, using two of the 33JV6 tubes per channel. They are not, as I understand the circuit, wired PSET. It nevertheless is a clear and highly resolving amp.

Regarding the question of TVC: I headed down the TVC route in lieu of an active preamp about five years ago after I sold my crossover-based speakers and migrated both my systems to Zu. At the time I got the Django TVC assembled by DIYhifisupply, in the S&B TX-102 transformers option, with all internal wiring in silver/teflon. Shortly after that, the US importer shom I've known for over 30 years, was in California and stopped by with his first Music First sample and we compared them. Music First, the integrated products arm of S&B, calimed then that their own version of the TX-102 was in some unexplained way premium to the version they were then selling to other TVC makers, and as I understand it today, a Music First product is the only way a hifi consumer can buy a TX-102 based TVC new.

Regardless, the S&B xformers were and are among the best, and TX-102s including in Bent Audio, DIYhififsupply and other vendors' products were unconditionally excellent. The Music First TVC (what is now their "Classic") was very marginally, just perceptibly more resolving than the Django. It was a very small difference. And some of it could have been due to the Django's steel chassis against the Music First's aluminum. Switchgear, internal wiring and workmanship were fully competitive between the two, despite the considerable price difference (UK-made Music First more expensive).

At the time I had a variety of amplifiers and four active preamps on hand for comparison, three tube-based, and one the Audiopax solid state preamp on loan.

I liked the TVC, and still have the Django as my spare preamp. But it did not win out over my Audion Premier, nor my Klimo Merlino Gold, nor a Melody P1688 I was evaluating at the time. It did win out over my nearly 40 years old Stax SRA-3s tube preamp/headphone amp. I'll say more specifically that the TVCs -- neither of them -- were preferred to the active preamps with my Audion amps, which was interesting because of all the amps I had on hand at the time, the Audions had the highest input sensitivity, so even the +6db gain available wasn't needed.

The TVC did yield several sonic advantages driving Audiopax 88 tube monoblocks, and a pair of Quad IIs. Unfortunately, the input sensitivity on the Audiopax was very low, so the TVC couldn't drive them to full power with normal sources. At the time, to live with the TVC and the Audiopaxes for an extended period and drive them to full dynamic range with a TVC, I had a set of interstage xformers made from S&B TX103 step-ups, so that I could add another 6db of gain. Of course I had to be precise about impedance matching, but it worked with the Audiopaxes. On the Quad II, which have input sensitivity of 1.4v, I did very much like the refined presentation of the Django and Music First, and it has seemed to work well when anyone has brought a solid state amp to listen to.

So, on TVCs, I say your sound quality experiences will vary by power amplifiers. Into Audion Black Shadows and Audion Golden Dreams, the TVC sound is inferior to my tube-circuit active preamps, though I wish it were otherwise because the isolation and lack of an additional power supply definitely makes it easier to chase more noise out of an SET-based system.

Now, Spiritofmusic, on to your volume control range question. I get asked about this alot, so it bears explanation.

Your usable volume control range is not very much affected by the output power of your amplifier. Yes, with two power amps of same input sensitivity, the more powerful amp will deliver somewhat more power at a given volume control level. What you really need to pay attention to is the gain relationship between the preamp and power amp, and/or the input sensitivity of the power amp relative to the preamp's gain and therefore output.

For example: My Audion tube amps have input sensitivity of 0.7v, meaning a signal of 7/10ths of a volt will drive them to full power. Compare this to American amps that generally have an input sensitivity in the 1.5v - 2.0v range. You can see that, depending on the contour of a preamp's volume control and your sources, that generally if I use a power amp with 2.0v input sensitivity, I would get much more usable rotational range on my preamp's volume control. In fact I hint at this scenario in the discussion above. With a disc player having the standard 2v output, connected to a 0db gain TVC where all you can do is attenuate, I could not drive the Audiopax 88 amps to full power even with the TVC volume control turned all the way up, because the Audiopax's input sensitivity was greater than 2v. In a market where most power amps have 24 - 32 db of gain, the Audiopax 88 has only 18 db gain. On the other hand, the TVC set for 0db gain could easily drive the 0.7v input sensitivity Audion amps to full power with the attenuated output of a 2v out disc player.

So what to do when you use an active preamp? This is where input level control on power amps are helpful, because most gear has too much total gain in the chain. Right now, two of my three active preamps are fairly high gain -- the Klimo is 20db and the Melody 101 has 23 and 15 db options. But they each sound great with the Audions. The advantage is, my preamps are quieter than are my SET power amps (common for SET). So I can prioritize the gain in my quiet preamps over the gain in my noisier power amps by running the input level controls turned very low, effectively raising the input sensitivity by "throwing away gain" at the input level pot. This way, I get more usable rotation in my preamp volume control, and lower the system noise floor by reducing SET noise. It's not an amp power issue. I could put in an pair of 1200w McIntosh monoblocks with ~2v input sensitivity and have more volume control range than I'd have if my Audion amps didn't have input level controls, though there could be bigger consequences if the volume control were set too high. The point is, regardless of the power amp, you can choose a preamp/power amp combination that molds the gain relationship between pre/pwr to your operating advantage.

If the gain relationship or output/input sensitivity are not mated well, you won't get more useful rotational range from your volume control with a lower powered amp, but you might push the amp into clipping sooner. Make sense to you?

So if you want more usable range out of your preamp volume control with a given power amp, you either have to choose a preamp option with less gain or need a way to throw away excess gain via input level controls or find lower-output sources to eliminate the problem. A TVC gives you a 0db gain option or at most +6db optional, to reduce system gain, so if it in fact sounds as good or better than a higher gain active preamp, you will get what you're seeking irrespective of the power amp's output.

Phil