01 April, 2024

UMI 2 Clarity Plus S2 version 优美 1:1 Isolation Transformer

Click pics to enlarge. Top, Mila's complicated yet interesting rig. Stacked Stirling 3/5A (15 ohm version).

Letter from Hong Kong (24-12): ELO on UMI 2 (latest Clarity Plus S2 version), Part I
Home (Salon) Visit: A Quaint Hair Salon

Update 4/5/24: More essential details and info on the 5V DC power inlet.

Editor: I  have written several articles on the slightly older UMI 2 (for a start, see here and here) but it's great to have now the initial evaluation of the latest v2 by ELO! See sections below for the subtle functional, cosmetics and sonic differences between my v2 and his latest v2).

ELO's review of UMI 1

The long awaited UMI v2 (UMI 2) has finally arrived thanks to icefox for organising the group buy! As I mentioned previously, 4 for me and my friends.

Round 1, Chez Mila's
We had arranged pickup at his freind Mila's shop on Tai Ping Road in Sheung Wan, a quaint street with a unique vibe rarely found elsewhere in HK. I used to visit the area for taking street photos or just hanging around. His shop has a back alley which is arguably the cleanest in HK, just perfect for food and wine gathering with friends!

Me and Jo arrived at the shop around 7 pm to pickup our orders, one each for me and Jo, another for Kwong and the last one for another Hifi friend "Seven" who is now using Infinity Renaissance 90 and Lab12 preamp, and I can't wait to hear his system with UMI 2 in the mix.

Mila's place is actually a hair salon with a small but dedicated space that houses a very unique system. When I first look at his setup, I know he is a seasoned veteran as his equipment are definitely far from main stream, kinda like mine even if our systems are very different in direction of preference. After a short conversation with him, I immediately realised that he is more of a music lover  than an "Effects Chaser", and we do share the same belief on how a good piece of music should sound like. Afterall, it's music that we are chasing, not effects!

Before I describe the sound from his setup, let me make a run down of his interesting setup! I categorize him as like me, an " Itchy Ass" kinda guy, meaning we don't want to be tied up by the mainstream stuff and instead like to find our own way. Thinking of my system, I suddenly realised that it comprises products made in Denmark, Sweden, Switzerland, UK, Japan, Mainland China, France, Germany and Canada!  In it I used 6 earth boxes to kill background noise in order to achieve a low noise floor. Diversity and open-mindedness and know-how is what a music/hifi lover should have in mind all the time.

R, Cyrus One atop EAR Phono Amp (chrome)

Setup Mila uses Bluetooth to stream Tidal music. He is also a user of  H10U (variously branded as Kyoeon 友昂, You Sheng Heng 友聲恆 or Wenliang), the el-cheapo little BT device which Kwong introduced to me and which I had written about in an early post [Editor: Before the H10U, ELO used the H-9A and reported on it.  I then got the H-9A courtesy of ELO, written up here; still has it in SZ. It should be noted that in ELO's reports, he preferred both the H9A and H10U to the popular and well-reviewed iFi Zen Blue - this is illustration of this Blog's independence from commercial influence!]. I believe it has become a popular cheap yet effective musical device! He then uses multiple  Reisong signal transformers and Douk E6 as preamp (his unit does not have any tube ringing as reported by DJ!) Then through a generic red/black wire to a MCM Reverse/Inverse RIAA device that converts the analog output of BT into an RIAA signal, which is then sent to his newly acquired "EAR 88P" (Chinese clone)! Then the "EAR" converts the RIAA signal back into analog signal and send the signal to the early version of Cyrus One Integrated Amp driving two pairs of Stirling 3/5A, stacked!! What an interesting setup and I noticed he must have followed this Blog. M told me originally the Reverse RIAA unit was acquired to run in the EAR phono, but it turned out the system sound had improved to a point that it has now become a pivotal piece in his setup. What a beautiful accident! Sound from streaming Tidal has surpassed his Turntable and he told me he mainly streams music through Tidal now.

Unboxing the UMI2 was such a pleasure. It came in a box only slightly larger than the unit, with a snug and tight fit. The unit itself is sturdy, with near-perfect metal works, like my UMI 1, not surprisingly.

Before UMI 2 We had an initial listening session with Mila's standard setup before moving on to implant the UMI2 and my Studer cable into the system. Overall sound was musical, and was already quite good. His liking is towards a meatier midrange and I can understand since stacked (15 ohm) 3/5As were used!! The stacked Stirling's seemed to add some heft in the lower octaves [Editor: interesting as a single pair of the Stirling 15 ohm tends to be lean in the bass; perhaps this is the result of stacked pair!]. The overall sound was very enjoyable and analog, without too many Hifi artefacts. His setup, with a listening distance of only 6 or 7 feet, tends to be more upfront and in your face compared to mine (which is like seated at the 8th row while his is 3rd row). 

One thing  that I really want to comment on: the whole system does not make me feel the shortfall of using a mass market Bluetooth receiver in streaming music. Back some time ago, for a while I had used BT to stream music; even now, I still use the BT that is built in to my Aiyima A08 Pro to stream TV and Youtube videos. They sound really good but ultimately fall behind the my proper setup using WEA. With the addition of UMI 1, I began to feel the gap widening between the two. Having said that, I'm still enjoying streaming Youtube music videos thru Bluetooth . 

+ UMI 2 Then we inserted the UMI 2 between the EAR and Cyrus. Upon turning up the volume, the sound had taken a change for the better. The bass dug deeper and with better definition, and imaging had tidied up without taking away the musicality. Musicians seemed to have drunk some Red Bull's, suddenly more alert and played at their highest level. Shades and Colours were fantastic, the flow smoother, more toned up and conditioned in body, all to my liking. Also, reverbs and decays were portrayed nicely in the background. Very enjoyable indeed given the listening in limited space (around 100 sq. ft I would guess).

Mila told me that his experience this night was very different from what he had heard from the loaner UMI 2 that DJ had earlier left to his HiFi buddies in HK to audition. M would have joined the group buy based on what he had heard on this night, which in his opinion was significantly better than his previous encounter. This begs the question: Perhaps this batch of transformer is better in quality? I'd think, like many smaller brands, the designer feverishly chases after improvements, so any upgrades will be implemented into the next batch without changing the version number. Therefore, it is no surprise that the most current batch's sound is superior to the previous batches! [Editor: Because of this I spoke to Engineer Li of UMI and clarified the differences; see below]

Detour: "Studer" Cable Then we added the "Studer" cable into the mix, we experienced a slight softening and increased smoothness in the music, For me the "Studer" may be a perfect match to take away some kick and coolness from my Aiyima A8 Pro and UMI 1, but on his setup, which is quite rich in body, the sound, though still very nice, turned in a slightly different direction! I tend to think that "Studer" cables is more suitable for cooler systems.

I think Mila's system definitely benefits by inserting the UMI 2 into the lineup. I think it integrates musicality and hifi values seamlessly! I'd also recommend trying out an earth box, as the background can become darker and more valuable music information can be retrieved! 

Next time, I will bring my Wattson WEA and my Entreq Earth box over to try - should be quite interesting! BTW, some days later I went again with my family for a stroll around the Tai Ping St and Hollywood Rd area and there's a shop selling a vast array of precious stones and crystals across the street from Mila's salon. I bought another pack of tourmaline and a piece of black tourmaline for Jo for his DIY earth box project.

Round 2, Chez Moi
Recently, for no particular reason, the sound suddenly suffered a setback, becoming less engaging and the soundstage seemed to have shrunken slightly. Except for switching cables for comparisons I had not altered anything. DJ reminded me that he had similar experience before and that it will go away eventually. I had my fingers crossed but, sure enough, days later the previous musical sound returned in full and now I'm back in Enjoy mode, yeah!

My latest setup with Crystals everywhere; for decoration purpose only, LOL. Also another newly acquired Entreq Minimus Ground box in the mix~

I have now replaced the UMI 1 with the UMI 2 in my system and will let it run-in for a week or so before I would switch it back to my UMI 1. DJ had said that the sound traits should be more similar than dissimilar, which is also my initial feeling, though I think the v2 has a slight edge. I am curious about the actual differences when UMI 2 is fully burnt in. It is already amazing!

Editor's Note on Latest UMI 2, Clarity Plus S2 version
Things moved fast! Before ELO penned this article (I thank him for his efficiency - must have been motivated! :-) as he has always been by UMI), very soon after the event chez Mila's, from icefox via Wechat (as E) I had already received pics of the latest v2 and texts on the proceedings. I was a bit taken aback as, aside from the purported sonic differences, there are certainly ergonomic differences between this latest v2 and my slightly older v2. So, I decided to clarify the differences and just now had a long wechat with UMI engineer, the perfectionist Mr. Li. Here are the essences on common as well as new features.

Note the Latest Version says Clarity Plus S2
The back of the Latest Version is also different! Phase Switch still there, but GONE is the 300/600 ohm switch (only 600 Ohm now). Now, for both channels there are XLR/RCA switches, which
have more functions than meet the eyes (see text).

v2 Latest Version (ELO's) vs older v2 (Editor's):
  • Latest Version is Clarity Plus S2 This is silkscreened on the casing (see above pic; the previous v2 does not have this). ALL of ELO's comments above are based on this latest version! Mine is the older version without such words.
  • Trannies (core materials etc) are the same.
  • Circuit Board is the same, but re-purposed for the different Ergonomics [Editor: Wiring is certainly different and simplified].
  • No more 300/600 ohm Choice. Only 1:1 600 ohm now. [Editor: IMHO, this is a good move as I had found the 300 ohm to be not much of a higher gain and pretty superfluous. The simpler the better].
  • Phase Switch remains the same. [Editor: I have not written much on this feature before, so at the behest of Engineer Li some pointers here. On higher-end vintage equipment (Preamps, Phonoamps and DACs) there are often a Phase Switch to cater to those who care (even obsess) over phase. To put it simply, many older recordings, be it classical or jazz or whatever, were recorded phase-inverted. My experience is that in a good system it makes a difference to have the choice, but if one listens to a mix of the modern and vintage (as I), switching back and forth is barely practical even if the switch is at one's finger tip. On the other hand, if one deals with a Preamp that is itself Phase-Inverted, like the Goliath Douk E6 (referenced above), or most CJs, it pays to have a means to invert phase (instead of switching speaker cable polarities, which is my preferred way). With this statement, if you infer that the Editor thinks Phase-Correctness is more important in a Preamp than in a Recording, you are damn right. I'd not belabor the point here. Suffice to say, this is a useful feature].
  • Ground (New Feature) This is fascinating. According to Engineer Li, with the removal of the 300/600 ohm switch a new function is added. This is because the Center Tap (300 ohm) is now permanently grounded, circuit board repurposed to the dual channel XLR/RCA Switches, etc. It's kind of confusing on the back panel, but follow me: 1) No matter where the Switch Position, both XLR and RCA will work properly; 2) XLR, with its carefully grounded planes and differentiation of ground and -ve return, of course should be switched to XLR (unless your system is uniquely queer, and I hope not); 3) RCA is grounded when switched to RCA position, but floated when switched to XLR position! This is of great use to the minority of people who experience hum with trannies [Editor: sorry to say, imho these people have usually committed basic errors in setup; analog SUT users should be familiar with this].
  • DC 5V Input This remains the Same as in previous v2. USE According to Engineer Li, the 5V is used to operate the Switches, and not in the circuit path. The 5V has to be plugged in for: 1) both XLR Input and Output needs the 5V connected; 2) Phase Reversal needs the 5V. In RCA only mode Mr Li said, and as I've experienced before, even when the 5V is not needed, the 5V still changes the sound. Even a casual generic cellphone 5V source will make the sound just a trifle warmer. But my system does not need extra warmth, so I'm not necessarily keen, YMMV. Engineer Li stresses that a proper LPS 5V supply (they have developed one which we hope to test one of these days) makes a significant difference. Let's say this remains on our agenda. Since the feature is here, we should try it out! 5V Source For reasons unknown, rarely a certain 5V cellphone charger may not work. If that is the case, just switch to another one.
  • XLR/RCA Conversion Same This can be easily accomplished, but 5V is usually needed. IMHO, it's more than worth its price even if used just as a two-way XLR/RCA Converter. Very versatile tool.
ELO again: Geez, there are so many combinations to try: 1) ground or float; 2) invert phase; 3) 5V input. This is gonna take some time and I hope I will not have listening fatigue.

I have created a test list, already added up to more than 80 tracks that have unique hifi attributes! Of course, I have to find them enjoyable musically as well!

Some photos taken recently👆

Ursula's Paddington, Sydney

Spaghetti with grilled "Pipa" Shrimp, slighlty grilled meat which taste so sweet and with a bouncy texture. The sauce is to die for!

Osso Bucco. No need to decribe the bone marrow is as good and lush as what you can imagine. Served on the side is super green and fresh cucumber with enchovies on toast which is equally as delicious~

Grass Fed Beef Steak on Chinese Chili Sauce (LaoGanMa) Excellemnt beef grilled to perfection and the chilli sauce did goes well with the steak!

Side dish with peach, ricotta cheese and Iberican ham

Scallop on a bed of Spinach. Such huge, fresh, sweet and tender Scallop!

Went to a nice French/Australian Cuisine with an Asian twist name Ursula's Paddington in Sydney. Highly recommended!


  1. I have been using the UMI 1:1 V1 (the one with XLR and RCA connectors) between DAC and preamp for several weeks now with great success. Images are more solid and real sounding. I am even using ELO's solution of twin Sommer (Studer) cables. Now, if that source for US based users to order the Clarity Plus S2 would materialize I would order that as well.

    1. The realness is to a point scary indeed. So glad you enjoyed the UMI/Studer setup!! With UMI2 replacing my 1, I will wait for my ultimate preamp to hook up to my UMI 1........

    2. I have the UMI attached to the Douk U4 DAC. This little DAC has displaced my two other DACs -- one Border Patrol and the other Denafrips. It is quite amazing as is but with the RCA Command 5670 tube, a McRU LPS, and the CAD USB Control plugged into the USB B slot it brings it to another level. Now some (most) would question the sanity of adding $1000 to a $50 DAC but I had these items in my possession already. My next step is to follow the crazy update to the U4 by Yazaki-san from SPEC audio: https://jeffsplace.positive-feedback.com/todays-fresh-catch-iphone-adventure-with-the-improved-u4-by-yazaki-san/

      When connected to the UMI the soundscape is quite beautiful -- detailed. layered, and with great tone.

    3. Great to hear about the U4. Is yours the TDA1543 version or BB 2704?

    4. TDA1543 version

    5. Glad you enjoy the UMI! this is also what I have experienced. If you remove it from the mix, the soundstage will collapse and flattened. The most impressive thing to me is the true sin-curve portrayal of the reverb of natural instruments that seems to go and on forever!

      This is really interesting as You and Dr J are having high accolades on Douk products. Makes me want to get one for whatever purpose LOL. BTW, which Denafrip model are you using now?
      The problem with me is that my Wattson Audio WEA is so good both as a combo of digital transport and DAC that I am very tossed in breaking it apart into using separate transport and DAC. Perhaps, I could sell my Analog and acquired their Emerson Digital as transport with a Douk U4 modded, highly tempted but will it be better?!
      SPEC amp is always on my radar since I have been using their RSP-301 for speakers and their HK-3 wood insulator with satisfactory results!

    6. Understand the dilemma . I was very happy with my Silent Angel Munich M1T streamer/Forester power supply connected to either the Border Patrol SEi or Denafrips Pontus II 12TH-1 DACs. The Douk U4 was bought on a whim after reading the Yazaki-san articles. I thought how good can a Bluetooth DAC sound (using Qobuz)? My better half and i were shocked at how the sound improved when I put the stock U4 in the system. With each tweak (tube, power supply, etc.) it just got incrementally better.

      I admit I am on a bit of a low cost / high sound quest lately. It started when I experimented with the Volex J power cables that are recommended by the people at Lejonklou. This inexpensive power cable, some will call a throw away cable, actually made a positive impact when used with the Silent Angel power supply, the DACs, and preamp. They replaced $2400 worth of Puritan Audio Labs Ultimate power cables.

      Actually the quest probably started when I bought a Topping PRE90 when I reconfigured my system. I needed a balanced preamp to drive 50 feet of XLR cables to mono-blocks (Van Alstine M225). This "temporary fix" turned permanent since I could not find a balanced preamp that sounded better under $5000. Sounds strange but to my ears that is the case. My speakers, Fleetwood Deville, are quite revealing so changing a component is easy to determine/hear.

      Just yesterday I received the Douk T8 Pro preamp/equalizer to see how this would work. Still evaluating/breaking in but it is very pleasant to listen to. Sparkos is located about 20 minutes from me and I am having conversations with Andrew on replacing the JRC op amps.

      Such a long winded response but I am encouraged by the soundscape being created with well designed/engineered, short signal path components that buck the trend that bigger and more expensive components are needed for an improved system. Trust me, I have been there and have struggled with the cost/performance ratio.

    7. Wow, thanks for sharing. Your last paragraph really strikes a chord with me. Yes, given the current sorrowful state of climate, these energy efficient and decent products are the way to go. I DETEST much of the current fi. In America, "big" size sells for odd reasons. Do report back on the T8 Pro, very curious about your views - I have more to come for this product.

    8. Really appreciate your detailed sharing of your valuable personal experience on your hifi journey. Your post did bring out many interesting topics.
      1) How many hifi hobbyist purchase equipment by their eyes but not by the ears? I feel lucky that I can get out of the infernal and buy what I hear that sounds good! Plus all of us here at this blog are cheapskate in our pockets but with deep knowledge in other pocket inside our brains. I just spend what is worth to buy and try to digest all info available to me and best if can hear it for ourselves before buying anything!
      2) Chi Fi is here now and will be a major player in high end market, like it or not.
      If one is smart enough, one can easily build up a very decent system at less than 1/4 of the cost on what they could have done 10, 20 years ago!! I'm glad you had figured out a way, your own way to achieve that, or heading into that direction. There are also many who still fancy buying Daytina watches. And don't get me wrong, I'm a huge fan of IWC and JLC etc but right now, I don't want to spend that much as I usually tell time from my phone, lol
      3) Streaming music with BT. I have posted many times already and believe that bluetooth is quite good and musical! While it would take one to spend way way more in wifi/ethernet streaming to better it! But ultimately , I think streaming through ethernet is still better imo at least at this moment but it won't be cheap. I believe BT can achieve 70% performance at less than 1/5 or even 1/10 of the cost!!

      Do report on the update of your experience on U4!! Would love to hear!!!

    9. Dr J -- My initial impressions of the T8 Pro are that it is much more rounded in sound than the Topping Pre90. I have located some clear top RCA 6CG7 tubes, figured out the Sparkos op amp replacements, and would probably use a LHY LPS. Do any of your improvements make a dramatic improvement in the overall sound quality?

      E Lo -- I will circle back in a month or so on the U4 -- hopefully the upgraded version should be in operation.

    10. I use my SMPS to power it but I think the tube change makes a BIG difference.

    11. Also, would you email me? cheaptube@hotmail.com Thx

    12. I sent an email as requested a few days ago...

    13. I sent you an email! Perhaps it went into your SPAM folder????

  2. Wasn’t expecting an updated version so quick! I’ve used a Sbooster LPS on my non Clarity Plus v2 unit. The overall presentation is crisper, cleaner vocal lines, tighter drums, etc. The old iPhone 5V charger seems to mellow things a little. Interested to hear your opinions.

    1. Didn't expect an upmarket LPS would make such a huge difference! Rumors says UMI may issue a self developed LPS with their own transformers' needless to say, I'm drooling already!!!

  3. If using two XLR IC, one long (7M) and one short (1M) to connect the transformer between preamp and power amp, should the transformer closer to the preamp or the power amp?

    1. I'd use the long one between the transformer and the amp. The UMI works well in your system?

    2. I haven't receive the UMI yet, but I am using a Reisong between the CD player and Preamp few days ago, sound so far so good. Just to make sure, you prefer the long wire between UMI and power amp and short wire between preamp and UMI?

    3. Yes, as you said "the long wire between UMI and power amp and short wire between preamp and UMI?" But I remind you again that the best place for transformer is between DAC and Preamp (unless your preamp has digital inputs)