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
Phil, I'm curious as to how you're finding your 6s?  I have watched the web but apologies if you've posted impressions elsewhere and I missed it in the searches.

Jay
Phil, the longer the better, I have precisely $Nada in the savings account for Defs V. 
Getting the Druid 6 FRD into the Def form factor will require a new cabinet interior design, and even the mounting holes for the drivers have to be somewhat different spacing than in Def4. For doing all that it only makes sense to also apply the materials and construction methods from the Druid 6 cabinet, to next Definition. Then there are the decisions regarding the sub and electronics. Patience is your friend, and there's a good chance you'll need less of it than you might fear.

Phil


Talked to Zu the other day and inquired about Druid VI drivers possibly being and upgrade in the ZU Defs. Was told the driver assembly for Druid VI is very different and couldn't possibly be implemented in Def 4s. 
Also in the last year have made significant improvements to my AC with an Equitech wall unit and must say this changed the Def4 presentation significantly for the better. I knew the noise must be pretty bad because over time I avoided listening before 8PM. It's like it moved a lot out of the way and the speakers became a bit more charming. Actually more than a bit. Some instruments on familiar recordings make me grin a little. 
Well Phil, as you know I've made great strides w my Defs IV, fascinated to extrapolate where the Druids V to VI impvts you'll be commenting on might extend to future Defs V.
Eagerly awaiting Phil's review of the Druids VI. What he doesn't know about Zu sound, esp comparisons, is not worth knowing.
Phil, bated breath and all that.
Hi Phil, count me as a second person v interested in your thoughts on Druid VI.
I'm now a decade long customer of Zu, firstly the Def 2 in 2008, followed by the Def 4 in 2012, and Duelunds/Lundahls upgrade in 2016.
Now I've upgraded my room and power grid, and have taken my Defs as far as they can reasonably go.
For the first time in a decade I have slight doubts on sticking w Zu.
However a trusted friend who's heard my Zus, and Zus in a number of rooms, having been impressed (tone density and verve) and reticent (slight roughness and lack of transparency) in equal measure on them, has heard the Zus at Phil's (and wrote the MonoAndStereo piece), and was mightily impressed, so much so he feels previous misgivings have been swept away.
I expect to have Druid 6 comments posted later this month. There's a back story regarding why I chose to put RIAA in the digital domain for one tonearm in both of my systems, which I suppose I'll include since people seem interested. Both systems have two tonearms on the Luxman PD444 turntables, so each one also has an arm/cartridge connected to conventional analog RIAA/phono pre duties.

But, the A>D>A arrangement on the Ortofon SPU in the Druid 6 system, and on the Allnic Puritas in the Definition 4 system flummoxes everyone because it still sounds analog to them. Not that I don't take plenty of flak from people before they hear it.

Phil
Hoping @213cobra weighs in with his thoughts on Druid VI.  His system with Druid VI is featured in monoandstereo.com. 

Phil, you have an awesome system.  I don't know why but it kind of tickles me that you are converting your turntable signal to digital.  I wonder how many audiophiles fainted when they saw that.  ;-)
Dentdog thanks for the explanation.
Spirit, your "after midnight" sound (quality) 24/7 sums up the effect of balanced AC power just perfectly and couldn't be illustrated better 😊.
Charles 
Charles, I've had six dedicated lines since inception. The EquiTech panel now services each of these. So  the BPT unit is plugged into a balanced power source and runs the front end, so yes, in line.  The amps and subwoofer amps across the room are plugged into wall outlets serviced by the EquiTech only.
The Equitech unit is powered by 220V which I understand means balanced power into the wall unit as well. Very happy with the change.

Dentdog, I can categorically acknowledge your sentiments. I'm truly getting that "after midnight" sound 24/7.
And with the move to a more acoustically even and sympathetic space, the Def4s have never sounded better.
Dentdog, 
Do the BPT and Equitech units power different components of your system separately or are they actually in line with one another (two balanced AC power units)? I am a strong advocate of balanced AC power for audio components.
Charles
Marc, saw your new room in the interview on WBF. When I saw your photo sitting on the couch, said to myself now that’s a guy that’s having some fun.
I can really appreciate your taming of the AC noise, as I have sort of followed your lead. As the AC gets cleaner 
with ZU Def IVs it's like progressively watching a TV turn into a hologram. Those who don't see this approach can't fathom the realism that can be achieved . I recently installed an Equitech wall unit to augment my BPT 3.5 sig plus and things are starting to get spooky with the lights out. Happy listening. 

Has anyone received their Druid 6s yet?  Mine were supposed to have shipped any day now, but I didn't yet get a shipping notice.  I've seen zero comments anywhere of late, which has me curious as to whether any have shipped?  Has anyone else on this thread put an order in for them?
mrpaul, have replaced my stock spikes w Symposium Acoustics Rollerblocks Jnrs, sitting on their Svelte Shelfs.
After 5+ years with my Def IVs it’s time to look at alternatives to the stock footers that came with the speaker. I am looking for input as to replacement footers or stands you are using and the benefits that you realized from making the change. One of the options I am considering is the Isoacoustic Gaia I. Thanks in advance.
Regarding the "newest 100w dissipation Shuguang 845C metal plate." mentioned by Phil.

Anyone know where to buy it?  I can't find it for sale at the usual places.
Looks like Zu is going to keep the Druid V in production and the NEW Druid VI will be an upgrade... interesting. Can't wait to read what  Srajan has to say about the new stuff :)
saw a show report picture from HiFiStatementNet Magazine and it looks just like a normal Druid V... 
6Moons has a (not very good) pic of the Druid VI as part of its Munich Show report. It looks like Druid V.
I have not seen any pics of the Zu at the Munich Show but was the new Druid and Presence there?
Any new Presence would be a re-appearance of the original in a different form factor. If Sean makes it, it won't replace anything in the current line. It would sit between Druid and Definition. Presence as defined by the original, is a single FRD speaker with supertweeter + an active bass module ala Definition. So, more expensive than Druid; less than Definition.

Soul and Soul Supreme sit below Druid in the line.

Phil
What was the Presence speaker? What speaker would this new Presence replace? Soul? Soul Suprime?
Zu has to pace its new model rollouts, given the capital requirements of a self-financed company. What you're seeing in the reported content changes to Druid 6, the rumors about Experience and Presence is convergence of the past Zu sound families into a more coherent house sound, a general push to wring noise out of the cabinets, and a more rationalized speaker line with a logical price/features ladder.

For most of Zu's history to-date, there was a distinct voicing and presentation difference between the dual FRD speakers and the various single FRD models. This two-branches-of-a-Zu-sound was starkly apparent as soon as the original Definition joined Druid in the line. Druid was immediate, focused, bursty but vintage-warm. It sounded like you had an old-school triode amp on it regardless of what you connected to it. Definition by contrast had from its first version a cooler, faster, more diffused and impressively big stage at some expense to the solo performer focus and vocal magic of Druid.

Definition 2 moved some Druid traits into Definition, largely due to its overbuilt ply cabinet, compared to the livelier MDF-based Def1.5. Druid IV/09 revision cleaned up Druid bass considerably and began to address what many people heard as a rolled-off top end.

Definition IV and Druid V were the inflection points in the conversion of sonic traits. Druid V got a much quieter cabinet, the progressively more neutral Zu FRD, the Radian compression tweeter and a more perfect expression of he Griewe acoustic impedance cabinet. The result was the first Druid that had enough soundstage width for full orchestra and movie soundtracks, the snap and sparkle of Definition and sharply-improved dynamic and texture unity from its deepest bass through the midrange and treble.

Def4 kept and improved all its prior advantages in tonal neutrality, scale, snap and bass mining, but it gained focus and near-er field listening potential, got nearly the full dose of Druid's loved tone density and also gained improved unity between its deep bass output and the rest of the speaker.

Notwithstanding how fast the line below Druid catches up, Druid 6 will be a more neutral, blacker, snappier refinement over Druid 5. Presence will, based on the prior model, give you the option of Druid sonics with active bass extension, in a more room-friendly form factor than the 2000s version. Definition will continue its role as the constantly progressing true high-end speaker for under $20K, and Experience, when we get it, will be something on the order of the $30,000 speaker (pair) that shames what the rest of the industry offers at twice the price.

A voice-unified Zu line will end or at least curtail the selling-friction buyer debates about whether to get, for example, Omen Def with upgrades or Druid. Druid + subs or Defs. Because you won't have to choose whether you want Druid's compromises or Defs'. You will be able to pick your price, confident that you aren't having to sacrifice orchestral scale to get singer-with-guitar intimacy, or vice-versa.

A lot of this is being accomplished through materials research, trial-and-error and collaboration. The speaker architectures are not radically changing but materials combinations, improvements in manufacturing at Zu, along with their advancements in finishings constantly put new value in the line. What's coming has already been shown by what's been delivered since roughly 2009.

Phil
Hello all,

I was told from Sean about a month ago that the Zu guys were also going to bring back a new version of the Presence model and very possibly a new version of the definitions,and of course the new Druid 6.

He wouldn't commit much about the Experiences other to say that they are coming soon.

Very cool things going on at the Zu factory.

Kenny.

Looking for to seeing the new Zu product and Druid. Is it possible to have more "transparency" and "tone" in the same speaker?
http://6moons.com/audioreviews2/zu3/1.html
I own a pair of Zu Omen Def mk II's with the Radian upgrade and I will be receiving my Decware SE34I.5 SET amp this Wednesday!  Very excited - it's been a 3 month wait. I'll report on it if anyone is interested, but from what I've read I don't think I'll be disappointed. I currently run the Zu's with a cheap but decent sounding Musical Paradise SET amp with only six watts via Golden Line KT88's. Sounds darn good in my opinion. The great thing about the Decware amps is the lifetime warranty, point to point wiring and the fact that all your money goes to the components and not the box they come in. That's not to say it's ugly, but it's simple. Also you buy direct and don't have to pay a middle man, that and a 30 day money back guarantee. Check out their website, they are a passionate bunch. 
Phil, 6 Moons reporting tentative info the new Druid VI to be launched next month at Munich
Trickle-down tech from the yet to be announced flagship Experiences 
Russian Birch ply/composite resin molded monocoque cabinet, more stiffness and less weight
Nano Tech impregnated full range driver and Radian Supertweeters, again to max stiffness at lower weight
I believe the new Experiences will sport twin side-firing 12" subs, Boxer arrangement, one tuned for impact, one for tone/depth 
These 12"s will have eff close to the 101dB of the FRDs, enabling outboard First Watt SIT amplification, hence more continuity w FRDs if pwrd by tubes 

Any thoughts on all this? Does anyone know when Sean might be ready to launch the Experiences?
He's been working on them a VERY long time 
I have had the Melody M845 in my own systems for extended audition, with the specific mission to get it as close to the Audion Black Shadow as possible, through tube rolling.

These amps are made to a very high standard of build quality. The stock-tubed M845 is not nearly as fast, dynamic and transparent as Audion, but they are half the price, hence their attraction. The stock tubes afflict the amp with an old school, rolled-off, lazy sound, leaving the sonic gulf between M845 and Black Shadows enormous and out of scale to the price difference. Fortunately, you can close the gap considerably by ditching the stock tubes in favor of vastly-better replacements.

Working back from the power tube, the ubiquitous and prosaic Shuguang 845A stock tube has good dynamic shove, but it has a dry, chalky character with a stunted top end. If you needed to stay cheap, getting cryogenically-treated 845A improves things but you can do much better. The cryogenically-treated newest Psvane 845 (it's a "B-type" diskless-top carbon plate) extends the treble, opens up the sound and gives bass more discipline and depth. For an even more transients speed and transparency in the vein of Audion, us the newest 100w dissipation Shuguang 845C metal plate. The older 70w dissipation 845C works. Ideally power tube bias as stock is a little hot for that tube, so yu will get some faint cherrying of the plate. It's stable though and won't go runaway, and in my experience the tube life isn't severely affected. But if you want the 845C sound without either a re-bias nor nagging concern about dissipation, the newer 100w dissipation 845C is a drop-in.

Next, the amp uses a 2a3 triode as the driver. The stock tube throttles the amp's sonic potential. By far the best way to put some added punch and clarity in the mix once the 845 is sorted, is to toss the stock 2a3, replacing it with a KR 2a3.

Last, the input tube is a 6sn7. The stock $5 tube is notoriously bad sounding. You find these in a wide range of preamps and amp inputs today because they are cheap and reliable. Put it in your backup tubes drawer and replace with either a NOS RCA red base 5692. Alternatives in new production are the Shuguang Treasure CV-181 (which isn' really a cv181 at all but that's another story) or the Full Music/Northern Electric/ Sophia 6sn7. With the Psvane cryo 845, the RCA is a great match. With the somewhat colder sounding 845C, the Treasure CV181 contributes a little offsetting soul. Use a clean, objective power cord like a Zu Event II and you're golden.

The Black Shadows are still well worth their premium but tubed properly, the M845 is convincing at its price and you can settle in for extended satisfaction for a more approachable fee.

Phil
Charles, Phil,

I do believe the recommendations from the two of you have considerable merit. Recently was able to hear SET amplification  for the first time at a fellow music lover's home and came away impressed. Along with the suggestions you provide, the Melody M845 has also been recommended and I would like to get some feedback from someone familiar with these.
And Phil, yes assuredly I increase the volume to hear detail better. The SET attraction of nuance and tone is something that has me intrigued.
Appreciate the suggestions.




Dentdog,

Your room isn't very different dimensionally from the room my Definitions system is used in. That room's dimensions are 21' x 14' x 8-1/2', and it's in an open plan house, so there are substantial non-bounded openings on two sides. I listen 10-1/2' from the speakers.

It's difficult to know for certain what is aggressive to you vs. me. However, I've never hit any practical limit with my 24w Audion Black Shadow monoblocks (845 power tube). Same with my 24w Audion Golden Dream 300B PSET amps. If they were double that output, it would only yield a 3db difference. My room clips before the amp is the major problem.

You will always hear the limits of an expensive amp in some way. It might be dynamics. It might be sudden onset of harsh, odd harmonics clipping. It might be in terms of the definition and tone you sacrificed in exchange for more power. You also should consider whether you in the past have used volume to try to find more detail in your system. Many people do this without realizing and then find that they listen at lower SPLs after one or more upgrades. Hard to say. But if you truly fear that Black Shadows won't be enough, then you probably will need to make the jump to push-pull in the 80-120w range. An Audio Research REF75, for instance, using the KT150 tube, Quad Two-Eighty monoblocks, many other choices and all different presentation than Audion.

Line Magnetic amps are well built and sonically robust. They don't have the same speed and transparency as Audion's SET and P-P circuits but certainly very credible if you like their more old-school tube sound. That line is not my sonic recommendation, but there's nothing wrong with considering them from a quality of execution standpoint.

Keep in mind that Definitions have a powered sub-bass section where the sub amp's input is derived from the main amp output signal. One effect is this relieves the main power amp from having to drive large amplitude deep bass. The speaker's parametric settings will determine how work is divided between amps there, but nominally your tube amp will be doing very little muscling below about 35-40 Hz.

Phil
Dentdog,
I'm sure Phil would enthusiastically recommend his Audion amplifiers and why not? They have obviously served him extremely well for many years.  I don't know what your budget is but I believe that the Line Magnetic 219ia  (845 SET) or their 508ia  (805 SET) would be wonderful with the your Zu speakers. 
Charles 

Sorry for the delay Phil, room is 17' wide, 21' long and just short of 9' ceiling. Listening position around 11' from speakers. My system is listed in the Virtual Systems. 
Here's the thing: I have this thing about clipping, and from posters on here the SET amps are exceptional when they are pushed judiciously. Sometimes I push everything pretty good and would hate to hear the limits of an expensive amp. 
I will be picking up SET or PSET sometime soon, just trying to make the right choice. 
Dentdog,

What are the dimensions of your listening space, and how far from the speakers is your listening position?

Phil
I've had Black Shadows in a large room (25' x 24') and had no issues at ear bleeding levels. Sophia Electric may have an older pair of 206-based 845 amps if you want a cheaper option, or Melody if you want an integrated one.

For SS, Sean has been using the Pass XA series as of late. I had great success with DarTZeel and Valvet.



Phil (213Cobra) swears by Audion 300b PSET or 845 SET. Personally, I am happy with my 300b SET. Conversely, I found 45 SET or 2a3 SET amplifiers to be inadequate.

When in doubt, I call Zu directly; they are always helpful. Currently, Sean Casey travels and most often shows First Watt SIT-1 Monoblocks.
If the  speaker's 101 db sensitivity is anywhere near  accurate the 845 SET sure seems as though it would be sufficient.  Here’s one to consider,  Line Magnetic 508ia which is a 805 tube SET with 48 watts perchannel. 
Charles 
Looking to make a major purchase, an amp for my Def 4s. The Black Shadows seem to carry the day for a few users here but I question the power available. When I run the volume up, and I occasionally do, will I ever run into a situation where I have to tap it back a notch due to clipping? In other words, can I really rock out?
My whole time in audio the issue of headroom has led me to amps with an overabundance of power. Dare I flirt with power that leaves me disappointed when taking the expense of these amps into considreration?
FWIW-
I connected Atma-Sphere MA1 v3.3 and MP-3 to a pair of Zu Union’s and was favorably impressed.
I also had them connected to a pair of Vandersteen 2W subs using the M5-HP crossovers.
The Unions were upgraded with ClarityCaps last year, too.
B
My latest ZU Druid stage-2 upgrade kit has been shipped, i'm relly looking forward, it took a wile to same money on it, but i did it finally. 

It consists of the new Radian 850 tweeters, new tweeter lens, internal foam acoustics kit. It took nearly 8 weeks to custom made the kit. Thanks to Gerrit from ZU.

 
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