UMI 优美 Audio Amplifier Transformer 1:1 Isolation Filter

Letter from Hong Kong (23-9): ELO on UMI  优美 1:1 Transformer

Last Major Update Oct 22: More details on evolution and the different versions; Previous Major Update Oct 20, 2023: Editor's Comments added.

It has been a while since I have posted anything, unlike  Doctorjohn who went on a spurt! Bravo.

For the last few months, I have been busy in relocating to another flat. As I had lived in the previous flat for more than 8 years (13 years in the same complex), I had to give away a lot of stuff to friends, colleagues, Salvation Army and local FB giveaway group, and I also sold some  items through Carousell. Talking about disposal of hundreds of pounds of stuff and most of them hardly used and some even unused! I ended up renting a storage unit for surplus stuff!

Before moving, I hadn't had much time to focus on fine tuning the setup, just playing as BGM. It was not until the end of the first week of October that I had finally felt settled down as the new flat has begun to look like a decent place to live!

I then pulled out all the gear and started re-assembling the system. Since the Elekit TU-875 stock transformer had blown out, I have asked Ray to build a new power supply for me. 7V/3A and it is almost finished - can't wait! 

Meanwhile, I have finally got a chance to open up the UMI Signal Transformer (ST) that DJ bought for me. This unit will replace the ST that Ray had built for me. There are 4 colours to choose from and I chose silver which is very classic and eye catching. Build quality is extremely good, a CNC machined heavy metal box.

So the latest setup will be Wattson Emerson Analog >> UMI ST >> Aiyima A08pro >> Dynaudio Crafft/ Audio Physic Subwoofer

For accessories, I have used Entreq Micro kit on the network switch, Active grounding  box by Labahua Audio on Aiyima,  DIY tourmaline ground boxes for speakers as well the wonderous little pair of SPEC RSP-301 (see my last post) wooden boxes behind my speakers. IsoAcoustic board (pro model used for guitar amp) to support my amp and UMI ST, SPEC H-K3 wood pucks under my WEA, Linn Skeet under my Dynaudio Crafft, Revox/Sommer as RCA interconnects, Viard HD12 speaker wires and LAN cable. Luna Gris power cable to power the subwoofer. Labahua noise filter was also plugged onto the power bar/conditioner which I have been using the reliable and effective LongYu 

At first there was no sound coming out at all! Tried many different ways, and then brought the WEA to Square Wave and Ken reminded me that WEA must be hooked up to output of the Wifi Router! Silly me , now everything works seamlessly, WEA is so robust! Only myself is getting old .....

Without the Elekit TU-875 preamp, the setup sounds not bad at all. There is surely a difference but I didn't pay that much attention to my new environment, with  a slightly smaller living room and new setup. Therefore, it's really hard to pinpoint any difference. My living room's setting is unbalanced with balcony glass door (with thick drapes luckily) and open on the other side, so there's still some issues in center focusing.

UMI 优美 1:1 Transformer However, the more I listen to the new setup and with the UMI well run-in, the more I'm astonished about the sound to a point it's jawdropping! Every song that I played seemed to have taken on a new presentation -  way improved from before. What really had changed is perhaps the significantly lowering of the noise background; it's so much quieter that a boatload of micro details in the background were being picked up and that makes every recording more interesting and colorful! Soundstage seems to widen, but not deeper (partly due to my environment?). You can pick up the pppp effortlessly while dynamic has improved as well. Bass kick is still there and every instrument has more shimmer and air surrounding it. Imaging has improved as well as instrument separation. I can hear the harmony vocal more clearly without sounding detached. Microdynamics is also very good which is vital to make the sound more exciting. Music seems to take on a more solid and slower pace (in perception since the amount of info has increased) Even when playing loud, I don't feel any congestion, part of it due to the use of UMI but part of it due to the room I suspect.

Of course there is a drawback: the sound may sound a bit cool, but definitely not cold nor lifeless. I am very sure that insertion of the Elekit may fix this and be the missing piece in giving a bit more body and roundness to the overall sound without sacrificing too much speed and dynamics.

I have been actively looking for a deal on SPEC Class D integrated amplifier to replace the Aiyima/Elekit combo, but with the current performance, do I really need the "upgrade" ? My mind is struggling. I will update you on the performance with the Elekit hooked up to the setup. Having said that, as of now, I am still deeply impressed by the performance and sound quality of the little Aiyima A08 Pro!

https://m.tb.cn/h.5SXf9su?tk=zfPQWYBSWYJ

Editor's Note: Since I bought the UMI for ELO, of course I took the opportunity to listen to it before sending it to him. First, a few words about this 1:1 transformer. I attach the Taobao page and link. This is a Permalloy unit that has been raved reviewed in the Chinese press since its inception. Note they also made 1:2 and 1:3 versions for use with lower output devices like phones. I advice you NOT to buy those (due to impedance matching anomalies) and stick to the 1:1.

This seller could be more detailed in his ad. It seems the product has evolved a lot. Currently, they are selling a "Mk I" (with both RCA and XLR). Note that they have also made a more expensive "Mk II" that adds 2 features: a) Impedance Switch (the normal 600 ohm and 300 ohm; since both Mk I and II transformers are designed for balanced operation, a center tap is de rigeur and this can be easily accomplished). The 300 ohm tap can be viewed as an attenuated level control (ideal for many of China's overly hot recordings); b) Phase Switch, which can be useful for many who attend to this detail. Many older recordings are phase inverted, and some preamps too are (like most CJs and Douk E6).

The one reviewed here dates from more than a year ago and is RCA-only, a version NOT available now, and should be viewed as perhaps "Pre-Mk I". The current Mk I is likely similar, adds XLRs and is more expensive by a third. It would be an educated guess to infer that the RCA-only version does not have a center tap, whereas the Mk I adds it at an appropriate cost. It's arguable that the simpler and cheaper RCA-only version is easier to implement well. But, as I have mentioned, this 1:1 version has undergone evolution. I do know from research that they have changed the hook-up wires (not the transformer winding) several times.

Where should this thing be used? Well, basically it's an impedance matching device and those who use long interconnects (like I) shall reap bigger benefits. I think the greatest effect shall be between source and preamp. But, effect can also be heard between preamp and amplifier. Think about this, many HIGH-end products employ Input and/or Output Transformers (a great example would be the EAR 912).

Well, for sonic findings I must say I completely concur with ELO. I also found it astonishingly detailed and the stabilizing effect highly beneficial to the system. I also found it was a tad cool in my system. Mind you, I also had the much cheaper Reisong 1:1 counterpart, which I have mentioned now and then but never really formally reviewed. That's for a reason. In my system, I ended up using TWO, one between DAC and Preamp and another between Preamp and Amp. The Reisong saved me a lot of money and has a much smaller footprint. BUT, it's a fact that the UMI has superior bandwidth. Whereas, the Reisong is a little warmer and more musical, though some will find it a bit rolled off at both ends. I had only heard the UMI brand new (and not run in) and I still pine for it after its departure. I suspect I shall get a unit at some point (especially after ELO's opinion). It's not often that one hears a transformer that is so transparent - consider it a job very well accomplished. Would be curious to hear the Mk II also.

新三興, To Kwa Wan. Must try. So delicious!! 

Iced abalone very crunchy!

Pig stomach and chicken soup: such intense sweet and peppery flavour! Yellow colour due to the chicken I suppose; must order!

Grilled eel is so QQ and juicy, best in QQ I have had so far! Must try!

Shrimp toast , fresh shrimp, crunchy toast topped with condensed mild, perfect combo

Large Razon Clam steamed with two types of garlic and vermicelli; so sweet, fresh and QQ , best paired with garlic and soy sauce!

Oven baked chicken in copper pot , piping hot and tasty with garlic and coriander, even the skin is delicious, but can't eat too much of it....