Zu Druid & Definition Roundup


In separate threads about the Zu Druid V and Zu Definition 3 & 4 in this forum, several questions have been directed to me about the comparative merits of these models, supertweeter capacitors, and a variety of other variables. Rather than bury comments in those threads, I thought it better to start a new thread and focus any follow-up comments or questions in one place.

Over the past few weeks, I helped a new Definition 3 owner install and setup his speakers, after earlier having setup his loaner Def3s that had an earlier iteration of the supertweeter network. Additionally, I made a capacitor change on the high pass filter to the supertweeter on my own Definition 4 and Druid V speakers. For further perspective on this, I have lived with my Definition 4 speakers for the past 13 months, and my Druid Vs for the past three months. Prior to that, I have migrated through the Definition 1.5 > 2 > 4 upgrade path, and Druid “3.5” > 4 > 4-08 > 5 upgrade path in two discrete systems since 2005. Any search on Zu topics or my handle here will serve up plenty of commentary on Zu speakers, cables, suitable amplification and other related matters, so I am not going to attempt to repeat all of that here. But I am going to roll up a collection of observations in response to prior questions, that might help Zu owners understand the relative value of current options in the upper half of Zu’s range, as well as people who have never owned Zu but who are considering their speakers, to better grasp what they might gain.

Druid 3, 4, 5

My first Druids were a used purchase from a prior owner here in Los Angeles. It turns out they were one of the first 10 pairs of Druids made. They had been sent back to Zu in late 2004 to be upgraded to then-current configuration plus had full internal Ibis cabling. The first 10 Druids made had the Speakon connector for full B3 geometry from amp to drivers when using Zu cables (I did), along with parallel Cardas posts for connecting any other cable. When I bought this first pair of Druids, they were shipped to me from Zu, in what Sean called a configuration he approximated as “version 3.5.” That speaker hooked me on the holistic Zu sound, but it had a euphonic warmth and soft top end that was forgiving and not fully revealing. Nevertheless, that v3.5 Druid was addictive for its unity of behaviors, and much like the original Quad electrostatic its ample advantages made it easy to overlook its limitations. The v4 upgrade opened up the top end marginally and was welcome, but the Spring 2008 v4-08 upgrade to Druid was a big leap toward bringing Druid closer to the liveliness and open top end of Definition. Then Druid was taken out of the Zu line. I let the Essence aberration pass by. Sean got back on track sonically with Superfly but I preferred the Druid form factor so stuck with the dead-ended Druid 4-08 for my secondary system, all the time lobbying Zu – along with other Druid owners – to restore Druid in more modern form in their line.

We got exactly that in Druid V late last year. For 4-1/2 years, while Essence came and went, Superfly got the HO FRD and then Nano, Druid was static and falling behind. Version 4-08 still had some tone-density and focus that was sacrificed in Superfly in favor of that speaker’s livelier, burstier dynamics and somewhat more expansive scalar projection. Superfly also had a slightly more extended top end than Druid 4-08 so to most people it simply sounded more like a modern speaker should, than Druid 4-08. It also had a more complete Griewe implementation, for faster and more textured bass than Druid. Druid V addressed all that, and more. The more advanced multi-composite cabinet with integral full Griewe and the mechanical grounding of the thick aluminum plinth would have comprehensively improved Druid even if the old Druid drivers had been installed. But the advance of the Nano FRD and the Radian 850 in supertweeter use gave us a Druid form factor speaker that has the linearity and finesse of Definition, with the traditional focus, unity and tone density of Druid even more present and obvious than in any prior version. Druid V *is* the modern equivalent to the original Quad ESL, without the extreme beaming, the bass limitation, dynamic restriction and fragility. It just happens to deliver Quad-like unity and speed from dynamic drivers with much higher efficiency *and* power handling. Druid V is finally an uncompromised and uncompromising speaker that despite its price can be justifiably driven by the very highest quality amplification at many times the cost of the speaker, yet can put modest amps in their best light. Why would anyone drive Druid V with amplification that costs lots more than a pair of the speakers? Because the total design can leverage stellar amplification, and no other speaker today can duplicate the full combination of attributes that Druid V delivers. You can get even greater focus and unity, ironically, in Zu’s line from the ~$60,000 Dominance, with its radiused front baffle and three FRDs, but not with Druid’s lightness of mass, presence and drivability. No Magico at any price can deliver Druid’s pure unity of behaviors regardless of what you try to drive them with, and no Magico is as musically satisfying with such a wide range of amplifiers. Druid V laughs at the cacophonous disunity of a Wilson speaker. Druid V ridicules the dynamic choke points imposed on Focal speakers at the crossover points. In the same way that no one appreciative of the unity of the Quad ESL heard any musical value from the Infinity IRS or a Duntech Sovereign back in the day, a Druid V owner today can pretty much ignore the rest of the alleged “high-end” speaker market inflicting damage upon our hearing, with the exception of other Zu speakers.

Because of the newest Nano FRD’s ability to reproduce more musical scale than prior Druids, for the first time in version V, Druid is a credible HT2.0 speaker in addition to being a great 2ch music speaker. Also for the first time, Druid is now quite good for listening to a full orchestra, whereas earlier Druids fell short on scale for orchestral purposes. Druid V is the first “no-apologies” Druid. That’s not to say that Definition doesn’t have advantages for more money – it certainly does. But Druid V is now a true all-music, all-purpose speaker with no real musical limitations in practical domestic use, and if a lower linear limit of about 35Hz isn’t deep enough for you, there’s always Zu’s new subwoofers. It’s also extremely amplifier-friendly. And the Griewe implementation does a fabulous job of extracting solid, tuneful bass from low-damping-factor/rising-deep-bass-THD SET amplifiers. Druid V gets qualitatively better bass from 2a3, 45 and 300B SET amps than any unassisted (no powered sub) speaker I can think of.

Definition 1.5, 2, 3, 4

The 2004/5 era Definition 1.5 was a revelation in its day, for its combination of speed, transparency, resolution, scale, bombast and finesse while having very good unity behaviors and terrific amplifier friendliness. It was sharply different from the same-era Druid because of its extended top end, almost tilted a little bright, and for its impressive sub-bass foundation. It was a relatively big, bursty, lively speaker even driven by modest power. It also had two clear deficiencies: first the sub-bass array amp had no level control (later and quickly rectified for everyone after I pointed out the glaring omission upon receiving my speakers), and second, that v1.X Definition’s MDF cabinet “talked” at high SPLs, marring the clean and incisive sound with an overriding glare. In Definition 2, cabinet talk was dramatically reduced by introduction of the birch-ply cabinet structure, stronger baffle, more robust plinth and associated damping techniques. The voicing of the speaker also tilted somewhat darker but the net result was a Definition absent ringing and glare, cleaner at moderate SPLs and far less fatiguing at high playing volumes – even fair to say altogether unfatiguing. While Definition 4 introduced many simultaneous improvements, Definition 3 shows clearly how much cabinet talk was left in Def2’s “silent” cabinet. Def3 starts with a Def2 cabinet and gets additional bracing and damping during the upgrade and it is plainly apparent when you first fire up Def3s after being familiar with Def2, that sound emerges from cleaner, quieter noise plane in the newer speaker. Def3, while retaining Def2’s 4x10” sub-bass line array on a rear baffle, gains seriously-improved deep bass by virtue of replacement of the Def2 plate amp and level control with Def4’s D amp with parametric controls. The Dominance trickle-down Nano FRD gives Def3 a close facsimile of Def4 performance from lowest response up to 10kHz or so, but Def3 uses the older-generation Zu supertweeter, which cannot begin to match the beauty, finesse and spray of the Radian 850 supertweeter used in the upper range Zu speakers. Def3 sub-bass performance is not equal to Def4’s but it is surprisingly competitive. In the Zu FRD range of roughly 38Hz – 12kHz, Def3 is very close to Def4, separated by clear differences in cabinet construction and internal configuration that give Def4 advantage as should be the case. As you get above roughly 8kHz, where the Radian 850 in Def4 begins to slope in, the upper range of the FRD in Def4 through the Radian’s exclusive extension on the top are in absolutely every way contributive to an elevated sense of musical fidelity and realism.

Definition 3 would be a market-wrangling speaker not surpassed at 3 or 4X its price if Definition 4 did not exist. But it does. As good as the new sub-bass amp and parametric controls are for the older 4x10” line array on the back baffle of Def3, the 4x10” rear-firing cones can’t load the room as evenly and deliver the incisive unity of Def4’s downfiring 12” driver. As closely as Def3’s Nano FRDs match the same in Def4, the completely re-architected cabinet of Def4 allows the drivers to perform with greater neutrality and freedom from distracting resonance. And the Radian 850 sprays the loveliest and yet most objective harmonic content of any tweeter I can think of today. The combined effect of Def4’s improvements over the Def2/3 design make it a compelling upgrade worth every penny to anyone who can afford its price compared to Def3, and yet the bargain roots of rendering Def3s from donor Def2s yields a speaker that is astonishingly great for its sub-$10K price and is necessarily limited in the number that will be produced. Notwithstanding that Omen Def is probably the peak value point in a two-FRD Zu speaker, for true high-end applications, Def3 is the high-discretionary-income value point and Def4 above it is the luxury alternative that nevertheless has no non-essential waste in its composition or price.

Definition 3 or Druid V?

I get this question privately from time to time: “For less than $2K difference, Druid V or Def3?”

These two speakers suit different priorities. Ask yourself the following:

1/ What is your application? That is, do you use your speakers strictly for 2-ch music or is your system doing dual duty for 2ch music and HT2.0?
2/ How important is the bass region between 16Hz - 35Hz to you?
3/ What are you using for amplification?
4/ What is the size of the space you have to acoustically load, and how far you sit from your speakers.
5/ What are your music listening habits, and what are the 3 - 5 sonic attributes you most value to feel satisfied?

There’s not a straightforward answer to this question, without knowing the above, but it’s easy enough for anyone reading this to self-sort. Druid V will give you focus, tone density, top end finesse and beauty that Def3 can’t quite match; Def3 will give you spatial & dynamic scale, deep bass foundation, resolution and horizontal dispersion that Druid V can’t equal. Overlapping both are the speed, agility, transparency and shove of the Zu Nano FRD. So, having the honest self-awareness to know what satisfies you most if your finances force a choice, will yield a crisp answer. If you can’t live with the trade-off, that’s your signal to save, and save, for Definition 4s.

Supertweeter Network Capacitors

Recently, there has been a lot of new interest in capacitor upgrades for the supertweeter high pass filter in Zu speakers, particularly the Druid and Definition. I have not been able to listen to all the available and oft-discussed options. My Def2s and Druid Mk 4-08s had Mundorf Silver-in-Oil caps. I had my Definition 4s built with V-Cap CuTF as an upgrade over the Mundorf. My Druid Vs were built with Mundorf Silver-in-Oil. In January, at Sean Casey’s recommendation, I had Clarity caps installed in both Def4s and Druid Vs. My Duelund capacitors are back-ordered (well, Zu urgently needed my pair for a more demanding customer), so I await them. I have heard Duelunds in non-Zu speakers. There are a few things I can say about capacitors at this stage, with more comments to follow as I put more contenders head-to-head.

1/ Every capacitor brand, formulation and composition brings specific attributes and a sonic signature. None are perfect. Not even Duelunds. You tend to think that what is best in current experience is as good as it gets until you hear something better. I can understand why someone feels ecstatic allegiance to Duelund caps, while at the same time appreciating why someone else prefers V-Cap TFTF or CuTF or some other alternative to them. For example, Sean Casey takes the position that Clarity caps bring 85% of Duelund’s sound quality to Definition 4 and Druid 5, for less than 1/3rd the retail cost. Elsewhere on this forum, another poster relates a conversation wherein Sean said something similar about the Audyn True Copper caps (90% for 10%). I haven’t heard the Audyn capacitors so have no comment right now. I will say that if Clarity is close to Duelund results, then both are a clear improvement over Mundorf Silver-in-Oil. The Clarity cap is both revealing and exceedingly smooth. But the case for Clarity (and by extension Duelund if Sean’s assessment holds) isn’t a slam-dunk compared to V-Cap CuTF or TFTF. There’s such a thing as too-smooth. This is reminiscent of the same disagreement I have with advocates of “slow” voiced SET amplifiers compared to the quick and transparent Audion SET amps that are so unlike most other SET brands. Some listeners are strongly attracted to a too-smooth representation. A lot of instruments have some harshness and rough texture in their output. The Clarity sands a touch of this off, just like (but less than) the round-sound old-school SET amp voicings some listeners favor. The V-Cap has more snap & tooth in its sound, but it is also less forgiving. I’m still in trial with a decision about whether to stick with Clarity or return to V-Cap CuTF or TFTF – as well as Duelund – pending. No, don’t bother assuring me that I’m going to love Duelund caps. Just consider me open to being convinced, but also not assuming a priori I will be.

2/ All of these exotic film caps take time to settle in. Clarity sounds great fresh but then they put you through a few weeks of meandering performance. They seem to be sensitive to temperature during the infant hours of use. We’ve had an unusually cold December and January here in Los Angeles, and I don’t use much furnace heat (you northerners and east coasters should see what people in SoCal consider a “furnace…”). A day of 64 degrees in my house sets breaking-in Clarity caps back a couple of steps. A warm day with internal temps in the high 70s pushes them forward. Then they go through a period of sounding beautiful on simple music, but shut down with congestion and blur on complex music. And then they start being reborn again to reassert their original convincing impression, and more. You have to be patient with any change.

3/ The Radian 850 in supertweeter application in Druid V and above in Zu’s line is intrinsically smooth, articulate, detailed and lovely. Frankly every cap sounds great into it, with the worst and the best still within the realm of excellent. You’ll hear differences and likely develop clear preferences, but even the basic Mundorf Silver-in-Oil sounds fully credible and completely acceptable in the absence of hearing something better. But the advantage of upgrading the Clarity (or Audyn True Copper, I imagine) is unmistakably beneficial to Def3’s supertweeter, and any earlier Definition or other Zu speaker using it, is fairly dramatic insofar as you are paying attention to top end harmonic character and are influenced by it. Clarity really tames much of the comparative roughness in the pre-Radian Zu supertweeter, compared to all the stock cap choices put in those speakers. What I’m saying is, pick your cap for Def4 and Druid5, knock yourself out. Some will sound definitely better but all will sound very fine. But if you have a Zu speaker using the older supertweeter and have an appetite to give them a worthwhile refinement, get a Clarity cap network upgrade. The cost is very reasonable and the benefit is disproportionately large at the price.

4/ There may be a cheap sleeper in capacitors. I was discussing film cap upgrades with Bob Hovland a couple of weeks ago. He mentioned that his more recent research indicated that the material consistency of the dielectric in film capacitors (even thickness & density, absence of pinholes) is more influential to sound quality than specific materials themselves. He wasn’t suggesting that all more exotic capacitors might not deliver someone’s preferred sound, but he does believe an excellent sounding cap can be made from prosaic materials. SuperCaps has a relatively new family of “Robert Hovland Edition” film caps that are highly affordable. They are handmade in the US, comprised of non-exotic materials, highly inspected during build and sealed tightly. I got some samples from Bob to try in my tube-output DACs and the results exceeded my expectations by a wide margin. They are more than good enough to settle on, and are staying in the DAC (mhdt Havana Balanced). He is next very eager for me to try a pair of 1uF/1000v versions in my Zu high-pass networks. I don’t know what to expect relative to Mundorf, Clarity, Audyn, Duelund but it’s a trial too interesting to not undertake. I’ll post back results, perhaps after I can put Duelunds in the mix, too.

Enough for now. I’m happy to add comments if questions are posted. I am sure I will remember something I intended to write here, but forgot.

Phil
213cobra
Good points all around. I tried my best to clarify my opinions and the context from which they were formed. Rarely, are we so lucky as to have all combinations of gear available at the same time and in the same room. Equally rarely I would say are we so disciplined that we can control for all variables and properly assign those things we hear to universally accepted (and understood) language. If you pause to seriously consider, it's a wonder that "truth" can emerge out of the random trials and tribulations of geographically separated audiophiles at all. Yet, I believe it does...eventually.

If a listener's perception of power is disproportionately influenced by perception of bass weight, however, I'd also have to point out that if in the Sophia the stock 845A tube was replaced by the 845B, that alone might completely change the perception because the B tube substantially alters that amp's apparent bass traits, favorably for someone predisposed to valuing bass weight.

I don't overvalue bass weight, though I have (probably incorrectly) used it, along with bass texture at higher SPL's, as a proxy for the phrase "powerful sounding". Fair point on the 845B tube. I explored this option with Richard from Sophia on the phone; his response was to say don't change tubes. This amp is only tuned for the tubes that came with it. This, along with the inability to adjust bias without opening the chassis, ultimately drove me to return them.

I don't have any argument with Germanboxer's preference for Coincident and Atmasphere. He has been listening to *three* amps that the majority of audio buyers would envy if they heard them. If 8w Frankensteins deployed as a stereo pair meet or exceed his expectations for convincing musicality, which includes dynamic credibility, then that's all that matters because those are sonically excellent amplifiers for Defs.

"Dynamic credibility" is a good choice of phrase in this instance since I tend to evaluate amps much more on the whole before choosing how to communicate and assign attributes. If it's dynamically convincing, I spend far less time trying to parse how much more or less it is to another piece of equipment. I'm not a reviewer, but I don't mind attempting to add substance to this forum where I feel can.

If however he ever has a chance to hear a big-glass amp that delivers similar resolution with more shove, my guess is the point will be made. It costs much more, however, to get Frank-level resolution from an 845 circuit and that's the downside.

I would love to hear a big-glass amp that delivers similar resolution. If that is a pair of Audion Black Shadows, will the current stock Black Shadows meet this standard or are silver wound secondary's and signal path required? Are there other 845 or 211 amps that deliver resolution, tone and shove?

Oh, and one correction...I incorrectly stated that the Sophia amp I demo'd was a 205 driven 845 amp; it was actually the 206 Princess driven 845 amp...looked identical to the one on the 'Gon right now.

Jordan
I have heard the Sophia 845 amps multiple times over the last decade of their development. The first-gen chassis version was available in two configurations: the less expensive one using a 6sn7 as the driver tube, and the premium version using the 205D and later 206 power triode in the same role. The new version is built in a much larger, more robust all-aluminum chassis using the 206 driver.

The 6sn7 driver Sophia 845 was neither impressive nor seriously deficient. The list price was $6,000/pr. They were pleasant enough but the 6sn7 is barely up to the task that was assigned to it. The amps had triode glow and beauty, but lacked all the dynamic shove an 845 is known for. At the time, with far fewer 845 amps choices on the market, at their price they were fine for people who liked them.

The then-$10,000/pair 206-driver version of the Sophia 845 was much better; a truly convincing amplifier musically. I said for several years that if you wanted an 845 amp and couldn't afford the Audion Black Shadow, a used pair of Sophia 206-driver 845s were the next best thing. Once the new chassis amps were introduced, trade-ins of earlier Sophias made them regularly available for $3500 - $4500/pr. Those amps are highly responsive to tube upgrades, and are energetic and musical. They don't have all the finesse, expansive spatial dimensioning and the same agility as the more expensive Audions but they strike you as a very nicely balanced design. They are not more dynamic than they are articulate. They don't have stronger bass than they do top end. They are not more resolving than they are dynamic. Midrange is unmistakably by way of SET. These amps can sound dull or bright or correct, depending on the tubes mix. They do a good job on Definitions; they do a great job on leveraging the burstiness of Soul Superfly while leavening some of that speakers aggression.

The new generation Sophia 845, now $20,000/pair, disappoints me. The designer favors a needlessly complex circuit. To his credit, he has given the new amp a large power supply. But the amp sounds like a promising design pushed a few steps too far. It's essentially a scale-up of the older 206-driver version and the fine balance of factors present in the older amp has been lost, in my view.

I heard these amps twice, both in another person's room on Zu and in my own home. The new amp is a high resolution 845 but it is relentlessly aggressive. It's tonally and dynamically forward to a fault. There is more aggression than finesse, which causes the amp's very fine ability to present nuance to be masked by its steroid overkill. I imagine that some of Sophia's customers who listen through less efficient, crossover-intensive speakers may like this. The aggression of the new Sophia 845 punches through the fog of passive crossovers and multiple drivers' disunity behaviors. But what it punches through with is musclebound & overstated. Through wideband, crossoverless and ultra-responsive Zu, the new Sophia enlarges (and enrages) every note it hurls. Even chamber music played quietly comes to sound a little angry. Through the new Sophia, every musician is in a bad mood. OK, authentic for Glenn Gould even if overdone here, but the Sophia makes even Arthur Rubinstein sound snarly! The amp's emotional tilt is dark. The tonal tilt is bright and in your face. Bass is very strong -- more impact & slam than from the Audion Black Shadow.

In the same period that Sophia's 206 driver 845 amp has increased from $10,000/pr to $20,000/pr, the Audion Black Shadow has increased from $11,000/pr to $13,500/pr. The Audion has only gotten better in all the ways it was already good, preserving its balance along the way. It's a simpler circuit and it has proven anvil reliable. It outclasses the new Sophia in every manner except for sheer bass slam where the Audion is not slouching. So whereas the Sophia 845 was once the more plentiful (in the US) and affordable alternative, it is now more disturbing to hear, less nuanced and less balanced for more money. Some people will like the Sophia's aggression but it has lost its place on my recommended list. The Melody M845, *retubed from the stock glass,* is now the next best 845 to Audion, in current production at a lower price.

Phil
The evolution of the Sophia 845 is regrettably another example of added complexity in a circuit resulting in poorer performance. Why can't designers resist this path and recognize that simpler is better.Simple well executed circuits result in better music reproduction, tone, dynamic nuance, inner details and naturalness. They will ultimately provide deeper emotional involvement convey more realistic presentation.

It seems from Phil's experiences the Sophia 845 is more hifi but has lost some musical soul and communication. Perhaps it's more impressive from an engineering stand point but fails where it matters most.Are simple circuits harder to implement successfully?
Regards,
Phil, I see that both Sean and Christian of Zu have their Audion Black Shadow SETs for sale via Ebay, Zu moving over to SIT power amps. What are your thoughts on this, it seems strange timing that BOTH of them would be passing along their Audions?
>>...I explored this option with Richard from Sophia on the phone; his response was to say don't change tubes. This amp is only tuned for the tubes that came with it. This, along with the inability to adjust bias without opening the chassis, ultimately drove me to return them....<<

Richard always says that. It's nonsense. The 845A and 845B have the same bias requirement. In fact, after guiding a local friend into old chassis Sophia 845s we staged a listening comparison between the A, B & C tubes. The B was best and that's what he ran with. Some time later he had a power supply capacitor give up and the amps were taken to Bob Hovland for inspection and repair. I made a point of asking Bob to check the bias and other operating parameters in the amp with the A & B tube and change any that needed to be optimized for the B. Everything was the same for both tubes, and what he found was that the factory bias was not spot on for either A or B. What Richard means when he says the amp is only tuned for the tubes shipped in it is that he *voiced* the amp to his preferences and he wants you to buy any new tubes from him.

Further, most 845 SET amps do not have "fixed bias" (ironically meaning adjustable bias), so that's no reason to turn down an SET 845. They are set up for the RCA spec and will work with any tube that conforms. Otherwise a tech simply has to make a resistor change.

>>If that is a pair of Audion Black Shadows, will the current stock Black Shadows meet this standard or are silver wound secondary's and signal path required? Are there other 845 or 211 amps that deliver resolution, tone and shove?<<

The current production Audion Black Shadows meet the standards of sound I describe. Mine have copper xformers, but all silver signal path wiring. Until recently, that's the only way Black Shadow was made. Now Audion allows you to order it in "Levels" just like the Golden Dream, wherein one of the variables is how much silver do you want to pay for in the xformers -- including power. My Golden Dreams have silver secondary windings and I have no doubt that silver in the xformers of Black Shadows will yield the same advantages. But it's not necessary to have silver there to get an outstanding amp. But if you do, yours will be better than mine, no doubt!

Having just spent a few weeks with the Melody M845, I think they have real potential, particularly if biased for a metal plate 854C or a KR 845 (along with filament feed changes if needed). I also think there is a lot of leverage in that amp in going with a very high quality 2a3 driver tube, like a KR or EML. It has shove, very good tone and while it falls somewhat short of Audion's resolution & speed, it's quite credible, for less cash. The M845 isn't as finely balanced in traits as the Audion, but it's less than half the price. It comes closest to equaling the Audion on shove (owing to its large power supply), is a step behind on tone, a couple steps further back on sheer resolution (but still very good), and falls somewhat further behind on speed and transparency, where I think ultra premium tubes can narrow that gap.

The push-pull 845 Nagra amps have lots of energy and very high resolution, with their depression on the polar curve being in tone. Then there are a proliferating plethora of 845s coming out of China for as little as $1500 up through the Shuguang premium amps and I haven't kept track of all of them.

Phil