Interesting comments. I'm thinking about purchasing a pair of Union 6 Supremes for my current and future system. Right now I'm using a Cayin A-50T integrated amp that I've had for 11 years. I realize it's not at the upper-tier of "audiophile" but it's served me very well. I have a Decware 25th Anniversary 2.3W SET amp on order that won't arrive for a long while. I rarely swap gear - I don't enjoy swapping gear - so I want my new system to be a keeper. My listening room is 15x11. All this time I've been using little Totem bookshelf speakers that are impressive for their size but have barely there bass. The Zu U6S would be a major step up. Would you say I need an EQ? One thing that concerns me is that these speakers get 400 hours o factory burn-in before they even ship, and here posters are talking about how they need far more to sound like they should. Isn't that a design problem? 400 hours of play is a hell of a lot of play. Am I looking at the wrong speaker? Will the U6S sound terrible using my Cayin in 16W triode mode? Maybe the DW6? Any advice is appreciated.
Zu Audio Union 6 Supreme
I thought I would post my experiences listening to a new pair of Zu Union 6 Supreme in my home system. I wouldn’t call this a review. As of today, I’ve had these speakers in my home for a little over two weeks and they are still changing.
I have a “main” system consisting of a Kuzma Stabi R table, Pass labs phono and pre feeding a Vandersteen HPA-5/Vandersteen Quatro Wood speakers. My ears are used to the amazing imaging, full range, mid-hall perspective that this system delivers. The living room space is open but untreated and acoustically challenging. This is the system I have documented on Audiogon.
In a second basement system, where acoustics are much better for a more first row presentation, I have been enjoying a system consisting of a Lyra Etna SL on a Kuzma Stabi arm feeding a Sutherland mini loci pre or a Bel Canto E1X streamer/DAC as front end. These signals go to a Decware Torii MK IV and a pair of Lii Audio Fast 15 mounted into nice wooden cabinets with a front port. This presentation works best when augmented by a pair of subwoofers as the Lii drivers don’t output much below 50hz. What I love about this combo was the amazing clarity of the Decware-> Lii crossoverless combo. It is holographic an immersive and fun. All the clichés about hearing new things in the recording and meaningful music information apply here. The high frequency extension isn’t there but not missing enough to sound dull, complex music can get a little congested but not distractingly so. The drivers in this speaker cabinet can have a boxy sound in the upper bas region that was improved with additional speaker The main issue is the need for subs which eliminates the ability to go direct from phonostage to the Decware as my current subs require a home theater processing (that the Bel Canto can do). The sound of the phono digitized through the Bel Canto isn’t as nice as the clarity of the direct all analog connection.
Fast forward to Apona last year where I got a chance to hang out in the Zu Audio/Kimber cable room. Here, a cable switching system had ben set up with duplicate Pass XA25 amps and Zu DWX to demonstrate differences between different “kable” looms. I had a chance to talk with Sean Casey of Zu and was able to get a morning demo of the pair of Union 6 speakers without all the cable switching shenanigans. This demo peaked my interest in the Zu approach of high efficiency, crossoverless design. I liked the clarity, big soundstage, excellent bass integration and energy of the system. I got the feeling they would work well as a full range speaker in my current second system with the wide variety of music I like to play (similar to what Sean likes to listen to as well).
Although Sean warned that the Union 6 Supreme version of the Union 6 (Jupiter caps on the tweeter high pass and their Event internal cabling) requires a longer break in and can be ruthlessly revealing of upstream amplifier quality (I believe he described them as a “mother bitch”), I ordered a pair this October (2024). I received the pair in mid November and they are beautiful speakers. Zu had excellent communication of the process and ships these speakers in individual boxes.
I subbed out the Lii Audio custom speakers and did some basic speaker placement maneuvers to get the frequency balance and imaging optimized. The speakers are about 8 feet apart and I am sitting about 8 feet in front. They are 32 inches from the side wall and 48 inches from the front wall. The speakers are only slightly toed in. I have been playing them frequently and they are coming along nicely. Here is what I have noticed so far. They image spectacularly, they have excellent bass response without the need for sub augmentation in my system. They have a slight warmth to them that brings out color and tone of the music. Maybe the result of putting everything through a 10 inch driver? On digital recordings, I employ the subs below 80 Hz and roll off the bass to the mains below 80Hz. I prefer the all analog Lyra/Kuzma/Sutherland path for its clarity and coherence which has no subs or mains crossover. My impressions are that these speakers mate well with the Decware ~26watts of Class A push-pull and zero negative feedback. Decware amps are not warm or "tubey" sounding.
On both digital or analog paths, I am hopeful that the Union 6 Supremes will mellow out with further break in. They can sound quite forward on certain recordings which would be more pleasant if they didn’t also have a harsh edge to them. From what I've read from other Zu model reviews, this quality can be tamed with time, so I am hopeful. This forwardness necessitated a swap out of PSVANE PH EL-34s in the Decware to Tube Audio Doctor KT-66s. These KT-66 are too mellow for my tastes with the Lii Audio speakers but make 90% of the recordings sound great with the Zu Union 6 supremes. My next move may be to swap out my Etna SL with a Koetsu Rosewood Signature Platinum I have in the main system. I'll give them more weeks of play regardless.
To summarize. I made a move to Zu Audio and am excited about what I hear in a second tube based system. They have some breaking in to do but I’ll continue to post on this thread about how they are morphing. Hoping to hear from others with experience with Zu, tube amplifiers and high efficiency speakers as well.
- ...
- 39 posts total
Thanks for keeping this thread alive! I also have an update. My last post indicated that I was really satisfied with the U6S being driven by the Decware Torii. That is still true. Since I last posted, I wanted to see how the system sounded with the integration of subwoofers. The two subs I had on hand were Vandersteen V2W. These are home theater specific subs with no real control for crossover level. So in order to integrate them, I added an external crossover, a sublime acoustics K235. I really liked what these subs added and eventually decided that a better match would be a pair of Zu subs. This would allow me to eliminate the crossover. I talked with Sean at Zu and we decided for my needs a pair of the Method Subs would do the trick. They are currently being made in matching Mercury Silver. In the meantime, I have sold the Vandersteen subs and the external crossover (which I recommend whole-heartedly). The next surprise was the opportunity to buy a Decware SE84UFO with level 2 upgrades and a Sophia Aqua III rectifier. I listened to the SE84UFO-Zu combo for a month and did a little signal tube rolling to get things cooking. I agree with @zbiener, the bass with the SE84 is super fast but not as extended compared to the Torii. When I put the Torii back in, I was able to hear more information in the low frequencies but lost a little of the SE84's single ended smoothness. I think these speakers like more power despite their 99db efficiency. It should be interesting to see which amp I prefer with the addition of the Method Subs. I will report back for sure. |
There is something about these high efficiency drivers that do require lots of playing time to sound more natural. I don't think this is a design flaw. This is what it takes to achieve the amazing transparency that comes with time. You can hear it right away, it just gets more natural and relaxed over the first year of play. I bet the Zu would sound really nice with your Cayin A50T. Another speaker line that many Decware owners pair with their amps are from Omega. Lots to choose from in their line too. |
I've never heard a Cayin amp, so I don't have any direct advice. In my experience, if it veers towards a harsh top end, then I would stay away. But tube amps are not often like that. As you can tell from my comments above, I think that if you are looking for a meaty sound, then DW6 is likely to fit better. U6S are more refined. And as Zu plainly states, they are more finicky about equipment pairings. If you don't enjoy trying out equipment, I'm not sure I would go that route. One of the reasons I chose to go that way is purely educational: I like evaluating different set-ups, and I wanted to learn what a "finicky" speaker might mean, and what "vivid" presentation (as Zu claims) amounts to. What I learned that is, for me, "vivid" translates into a really detailed but someone pronounced top-end, and "finicky" means that you have to have an equally opinionated amplifier to get a more balanced sound. My ears. YMMV. I will say, however, that I moved to the U6S from DW2 because I thought the top-end was lacking in the DW2. I would have liked something between U6S and DW2. Perhaps I should have tried the regular U6, or the new DW6. But I did have a short conversation with Sean from Zu in which he said that the U6S are actually more forgiving that the regular U6... so who knows. None of these words mean much until you actually listen. I did also try U6S with the Linear Tube Audio ZOTL40 Reference+ amp, which I will report on later when I have time to write more carefully. |
Thanks for these responses, they help me better understand the speaker. I’m going with the U6S. The DW6 looks appealing, but I want to go in the direction of top/mid articulation over something that emphasizes bass. Nor do I want a "polite" speaker, and I’ve heard Omegas described that way. For over a decade I’ve been getting mostly satisfying sound for me, but when I bought these bookshelf Totems I was living with roommates and listening mostly in my bedroom. They were perfect for that. Now I own my apartment, and the listening room is a small-ish/medium rectangle and that might actually help the U6S’ bass. The positioning in my room should be pretty straightforward, but I have a bit of space to angle/move them. I usually sit off center by 2-3 feet on a couch, but sometimes I’ll pull up a chair, centered. Anyway, this will be a major step up in sound, and I’m looking forward to hearing it. One thing in the back of my mind is that I might want another phono preamp that allows me to adjust gain settings. If the U6S is a little forward sounding, and I’m using the Cayin in 16W triode, I could lower the gain, and adjust again when the Decware arrives. Did I mention I don’t like swapping gear? I say that because if I find myself obsessing over gear, I remind myself that some of my best listening experiences involved "bad" equipment. A cheap little boombox in my childhood bedroom gave me so much joy. People pay fortunes to achieve that feeling. I really like the Cayin A50T, BTW. Even after the Decware arrives, I’ll keep it. Using the Cayin in triode mode made me want to explore the low-watt SET / high efficiency speaker sound. |
- 39 posts total