SOtM tx-USBultra USB Signal Regenerator

photo credit: SOtM

Device Type: USB Isolator / Power / Reclocker
Input: USB B
Output: 2x USB A
Power Requirement: 6.5V ~ 9Vdc (Optional 12Vdc)
External Power Supply: Supplied with the standard 6.6 ~ 9Vdc model
Dimensions (H x W x D): 47mm X 53mm X 123mm
Weight: 1.5 Kg
Availability: Direct / Authorized Dealers
Price: $990.00 (as evaluated), $1200 with Master Clock Connection Option

USB performance improvement devices have proven to very popular with computer audiophiles over the last several years. It seems that before I can turn around, a new offering appears promising improved sonics from one’s USB DAC. Installation of what I like to refer to as USB enhancement devices is just a matter of connecting the device between your computer / server USB output to the USB input of your DAC. Perhaps it has been the simplicity of use without worrying about the installation of drivers or other complicating factors that has fueled the unending popularity of these products with users’ passionate expectations of improved sound. I can think of no less than 3 new devices that will be forthcoming from iFi Audio, UpTone Audio, and now from the Korean manufacturer, SOtM.

photo credit: SOtM

The tx-USBultra Signal Regenerator is actually a combination of two existing SOtM products: the tx-USBhubIN USB audio card and the newly upgraded sCLK-EX clock board.

Features of the tx-USBultra Regenerator

  • Ultra low phase noise custom designed oscillation circuit
  • Isolated differential clock signal circuit
  • Wide operating voltage input range
  • Active Noise Canceller / USB port Signal Noise Filter
  • USB port power on/off switch
  • 2 USB outputs
  • Ultra low noise regulator
  • Option for external 10MHz Master Clock input
  • Use of external high quality power supply
In summary, the tx-USBultra Regenerator supplies clean power to the USB DAC (or no power if not needed), filters the signal, and regenerates the USB signal with the use of an ultra-low noise clock for reduction of jitter that corrupts the audio signal.

I used my Ayre Acoustics QX-5 Twenty DAC in this review; a DAC that supplies its own 5v power to the USB receiver and employs a custom master clock that is one of the best in the industry.

I asked Charles Hansen, co-founder and Research Director at Ayre Acoustics, why these USB enhancement devices seem to have an effect on a sophisticated well-designed DAC such as the Ayre Acoustics QX-5 Twenty?

"Please don't be misled by the word "clock". The QX-5 has an insanely good master clock that runs the DAC chip, giving the absolute best sound quality. However both USB and Ethernet inputs have their own separate clocks. The USB clock is a multiple of 12MHz and the Ethernet clock is a multiple of 25MHz - neither related to the digital audio master clock frequencies that are multiples of either 44.1kHz or 48kHz (two separate crystals used).

"Ayre has done everything possible to elicit the highest performance from each type of digital source. Yet the quality of the source still makes a difference. Therefore improving the quality of the source on any input will make some difference to the sound.

"You may recall that when Gordon Rankin (Wavelength Audio) developed asynchronous USB, he and I both thought that the source would no longer matter. However we were wrong. Not only does the source still make a difference, but it even matters if you are listening to 'flat' files or losslessly compressed files."

photo credit: SOtM

Associated Components
For the evaluation of the tx-USBultra Regenerator I used my Asus G701VI laptop running Windows 10 Pro 64 with the AudiophileOptimizer software. The Asus served as my Roon Core running Roon Server on my network. The Asus G701VI possesses an overclockable Intel Core i7 6820HK processor with 32 GB DDR4 2400Mhz SDRAM and a very fast PCIe Gen3 X4 NVMe SSD. This laptop has 3 USB 3.0 ports as well as a Thunderbolt port (USB type- C). An NVIDIA GeoForce GTX1080 with 8 GB VRAM processes video. This powerful video processor allows significant CUDA offload processing for the Signalyst HQPlayer. The Asus laptop was plugged into a Shunyata Research Hydra DPC-6 v2 distribution center to firewall the noise generated by this computer from contaminating my AC line.

An SOtM sMS-200 Mini Network Player was connected to the tx-USBultra and run in Roon Ready mode. Power supplies used in this review were the Sonore Signature Series Power Supply to power the sMS-200, and the UpTone Audio UltraCap™ LPS-1 to power the tx-USBultra.

The Asus laptop was placed on a Synergistic Research Tranquility Base UEF grounded with the Synergistic Research High Definition Ground Cable / Grounding Block as was the computer. A G-Technology 16 TB G|RAID Thunderbolt 2 / USB 3 drive was connected to the Asus with an AudioQuest Coffee Thunderbolt cable. The G|RAID Thunderbolt drive was powered by an HDPlex 100w linear power supply plugged into a Shunyata Research Denali 6000/T power conditioner. The G|RAID Thunderbolt drive and its HDPlex power supply were placed on a Synergistic Research Tranquility Base.

As previously mentioned, I employed the Ayre Acoustics QX-5 Twenty for the DAC in this review. It was placed on a Synergistic Research Tranquility Base UEF and plugged into a Shunyata Research Triton v2 / Typhon with a Shunyata Sigma Digital AC cord.

The SOtM sMS-200 and the tx-USBultra were both placed on a Synergistic Research Tranquility Base powered by a Sonore Signature Power Supply plugged into a Shunyata Triton v2 / Typhon and the UpTone Audio UltraCap™ LPS-1 plugged into a Shunyata DPC-6 v2.

A .75 meter AudioQuest Diamond USB cable and a .5 meter Wireworld Platinum Starlight 7 USB 2.0 cable were used for the evaluation of the tx-USBultra.

photo credit: SOtM

There is not much to worry about concerning the setup of the tx-USBultra. Above each of the USB outputs, there is a small switch to select on or off for the 5v power to the USB cable. A small improvement in sound was observed setting the switch to off for DACs that are self-powered. Although there are 2 USB outputs, SOtM recommends that both USB outputs should not be used at the same time.

The Sound
The sound of the tx-USBultra Regenerator simply blew me away in terms of the overall improvement to what I had previously heard from the SOtM sMS-200 driving the Ayre QX-5 Twenty directly. I will cut to the chase; the SOtM tx-USBultra is by far the best USB enhancement device I have experienced - and I have had the pleasure to listen to a good number of these devices.

The tx-USBultra does not have a particular sonic bias in terms of sounding warm or bright. Almost all of the USB enhancement devices I have heard have a particular sonic signature. The tx-USBultra is the most neutral sounding USB enhancement device I have yet heard.

But let’s get down to the real reason I have gone gaga over this device. The tx-USBultra seems to remove a perception of compression from the sound that allows music to flow more naturally with greater clarity and resolution. The overall effect I heard was not small and easily identifiable. Complex musical passages were unraveled in a superior fashion that resulted in sound that seemed to be pure and direct.

Familiar recordings that I had previously thought were not well recorded now sounded beautiful with no traces of hardness or sonic blurring. The mid bass, while quite excellent when heard only from the sMS-200, underwent further enhancement in overall clarity when heard through the tx-USBultra.

Enhancement to the soundstage was apparent with greater depth perception and acoustic space with concomitant air around instruments and voices. No doubt, the decompression of the overall sound by the tx-USBultra aided the perception of soundstage with well recorded files.

I also enjoyed hearing improvements in overall micro and macro dynamics with an extremely low level of background noise.

USB Cables
I tried a number of different USB cables but settled on the AudioQuest Diamond and Wireworld Wireworld Platinum Starlight 7 USB 2.0 cables. My evaluations found that the critical USB cable was the one used from the tx-USBultra Regenerator to my Ayre DAC. The USB cable between the sMS-200 and the tx-USBultra was found to be less critical to the overall sound.

Power Supplies
I found that the tx-USBultra was quite sensitive to the power supply powering it. Even though this device comes with a switch mode power supply for those that elect the standard 6.5-9 volt option, I do not recommend that it be used. One power supply that I do recommend for use with the tx-USBultra is the UpTone Audio UltraCap LPS-1. While not cheap at $395.00, it does create what I felt was a synergistic union with the tx-USBultra. I also tried an HDPlex 100w linear power supply, but found the LPS-1 to be superior in dynamics and overall clarity. The Sonore Signature Series Power Supply also performed very well with the tx-USBultra edging out the LPS-1 in terms of midrange ease and naturalness, but at a significantly higher price of $1395.00. My feeling is that the UpTone Audio UltraCap LPS-1 provides the most bang for the buck, but for computer audiophiles with deep pockets, the Sonore was the better sounding of the two power supplies.

For those of you that are using the SOtM sMS-200 with the tx-USBultra, I would suggest placing your best power supply on the tx-USBultra. I obtained superior results, sonically speaking, with the Sonore powering the tx-USBultra and the LPS-1 providing power to the sMS-200.

The Music
Livingston Taylor’s new release called Safe Home (24/192) was sonically catapulted by the tx-USBUltra to a superior level of clarity and resolution that was a joy to experience. This recording is a Chesky Binaural + Series recording that is recorded with a single microphone. The SOtM tx-USBultra allowed the recording’s acoustic space to bloom with superb liquidity and harmonic richness to the voices and instruments. Listening without the tx-USBultra resulted in a slight hardness to the voices and a sense of compression of the acoustic space.

Well recorded orchestral recordings were a real treat when heard through the tx-USBultra. Sonic blurring of complex musical passages were reduced significantly allowing one to hear deep into the music with reduced electronic coloration. As I listened to the DSD64 recording Russian Dances performed by the Orchestre de la Suisse Romande / Kazuki Yamada conducting, I experienced rich tonal colors with outstanding resolution of inner detail. The reproduction of the acoustic space and soundstage experience were first rate with the tx-USBultra.

The tx-USBultra made a significant improvement to everything I listened to. Alison Krauss’ new album Windy City (24/96) sounded a bit constricted and a little dry-hard sounding when I first experienced this recording without the tx-USBultra. With the tx-USBultra, Alison’s voice sounded more natural with a lower distortion signature. The overall sound of this recording was now more relaxed allowing the music to flow effortlessly when experienced with the tx-USBultra.

photo credit: SOtM

I am going to have to admit that the SOtM tx-USBultra Signal Regenerator has permanently spoiled me when I elect to listen to USB audio. I have never heard this level of improvement from any other USB enhancement device and now find it to be a necessary component for my overall enjoyment of music. The SOtM tx-USBultra lifts a veil from the music that I didn’t realize was there when listening without this device. It is going to be very interesting to see how the new forthcoming batch of USB enhancement products compare to SOtM’s newest creation. But as for today, the SOtM tx-USBultra Signal Regenerator is the one for other manufacturers to beat.

Associated Equipment

COMMENTS's picture

I have been back and forth over which connection to use with my QX5/20. I'm running a Steve Nugent built Mac Mini server with a Paul Hynes LPS. It's as good as any of the servers I've had in the room from the N10 to a few of the smaller companies out there. I need more storage and think about getting a Melco as a NAS only device or a QNAP NAS etc.. I want to run Roon and I don't need it all on the net, although I have purchased a Wired 4Sound LPS unit with two LPS's (have you tried these Michael? You have sold me on this device using the AQ Diamond cables most probably, but I want to use my Tidal with the Ayre also. I was wondering how you would set up my system for the best SQ based on what I"ve shared and if you feel I need anything else, I'm all ears as you know. Looking forward to your advice Michael. Thanks. for all you do.

Steven Plaskin's picture

Hi ctsooner,

I have enjoyed reading your posts on the Ayre QX-5 Twenty at CA.

I wrote the review, but both Michael and I have experience with the QX-5 Twenty. Michael also has experience with Melcro / NAS. Perhaps he will want to add his observations to your questions.

After extensive experimentation, I have found that both the Ethernet and USB inputs can sound great, but different on the QX-5 Twenty. Initially, I felt that the Ethernet input sounded better, but found a similar quality sound with the SOtM sMS-200. Everything can make a difference. Ethernet cables, USB cables, LPS, etc.

What I am trying to say is that there is no one best way to experience the QX-5 Twenty. For me, the USB input is presently preferred with my current setup.

I have no experience with the Wyred 4 Sound LPS.'s picture

I will wait to see what Michael says. I want Roon and Tidal. I am using Tidal from the ethernet into the Ayre. I guess I worry about opening anything new on the Mac as it was Steve's server he used for the shows and is completely optimized for max SQ, but I need to add a larger HD. I can just stay with the old Amarra he has on it, but then I have to use my TV in the room and use a mouse to play everything. I really want to be able to control everything from one app that is on my iPad. That to me is Tidal either from the Mac or hooking the Ayre up to the ethernet like it is already. I got the Wyred because it has multiple LPS bays and I can have one for the Mac and one for the Ayre if I need to do it that way. I'm not good with computer set ups so I guess the question is can I get what I want with what I have? If so, what's the best way to add a HD and which one for best SQ and ease of use. I may be able to send the Mac back to Steve and have him rip the music off the current HD and get a Samsung 850 SSD of 1T and have him install it so I don't need another box or connection. Then I just need to figure out how to use Roon and Tidal right? If I only have the Mac and the Ayre where do I get the Tidal from and do I use this device with the clock feature to max out my SQ and ease of use?

So many questions, but I think you guys know what I'm looking for. I assume fewer connections are best. I will be using AQ Diamond cables for all hook ups either/and ethernet and USB as I have loved them. Thanks guys. Hope I'm not taking away from this thread. You aren't the only ones who have told me this device with clock is SICK good.

Steven Plaskin's picture

Tidal can be taken care of by Roon pretty easily in the settings if you have a Tidal account. I assume you will be running Roon on the Mac. Steve was probably running an older version of OSX,and to what extent it was modified is unknown to me.

Venere 2's picture

I see that this device and an Uptone LPS 1 are close to 1400$ US dollars. I believe Steve's praise regarding this device.

But, when a USB cleaner and reclocker and its power supply cost close to 1400$ US dollars, is it a good value?

For 2700$ you can buy an Aurender N100H. The N100H is a 2 TB music store and player. It does not have the shitty sound quality of a stock computer. Why pay 1400$ for this device and a good power supply, plus the price of a computer and an additional USB cable, when you can get a better all in one solution that will most likely be as good, or better in sound quality?

Steven Plaskin's picture

You have raised a valid point. It will be interesting to see how the UpTone Audio ISO REGEN at $325 compares to the tax-USBultra for those users interested in using a USB enhancement device.

Doak's picture

Hoping to see my ISORegen by next weekend.
Went from Regen to W4SRUR + Uptone LPS-1.
Will be interesting.
Honestly, this stuff seems to have gotten out of hand.
There HAS to be a better way than all of these Band-Aids.
Though since there's no doubt they substantially improve sound, I'll be what I must to get it.


mentt's picture

If you need buy so much components(microRendu, LPS1, SOtM tx-USBultra USB and so on) to make USB DAC sound good, why don’t we use Optical or COAX instead of USB and save huge amount of money? Why is advantage of USB here if your using dedicated streamers and not regular computers(PC or MAC)?

Absolute Zero's picture

Agree with you Mentt. The Corning optical USB cable is $109. A lot of the quality DAC's power the USB receiver locally as part of best practice design approaches so the Corning would work well.

I also have to question the build and design quality of a really expensive DAC because I can't see throwing $1400 at a sub $200 i-fi, HRT, Emotiva.

Bob Parish's picture

Because COAX is PCM only, and the magical sound is DSD!
More magical if you upsample everything to DSD512...

24bitbob's picture

Hi Steve,

Thank you for the very detailed review.

I was fascinated by your impressions on the sound offered by this little device: "The sound of the tx-USBultra Regenerator simply blew me away in terms of the overall improvement to what I had previously heard".

That begs the question of how good the sound was that you were listening to beforehand? By that, I mean if you were perfectly happy with what you were listening to before, and something comes along which 'blew you away', then how flawed were your impressions beforehand, and how much more is there to be achieved out of little boxes of electronics?

I ask this respectfully, and not at all menacingly, since it mirrors my experience over the past couple of weeks. I was the very satisfied owner of a Devialet Expert 120. As stylish and as good sounding a piece of hifi as I could ever wish for, or so I thought. You may know that Devialet have upgraded their model range and now offer a series of 'Pro' versions. I got regular emails from the company offering special upgrade pricing which I was loathe to follow up on, being very happy with my existing model. As the offer period moved to a close (which is round about now), and due to Fear Of Missing Out (FOMO), I went to my dealer who kindly allowed me to take home a 220 Expert Pro (The upgrade model I was entitled to) to compare it alongside my trusted 120. Well, blow me, by just about every criteria you care to mention, the 220 Expert Pro was so far ahead of the 120, that I couldn't plug my 120 back into my system.

Suffice to say, I happily forked out Euro 3,500 for the upgrade. Now, you could read into this how wonderful the 220 Expert Pro is, but alternatively, you could question why I was so pleased with the 120 (which I was) when something else comes along and handily beats it in every way.

I'm not sure whether to be delighted at the prospect of the new machine I look forward to enjoying, or chastened by my inability to decipher what was not right about the machine I was happily enjoying until then. I'll go with the former, of course, but I do so with a measure of humility.

Steven Plaskin's picture

It never fails to amaze me when something comes along that makes a big improvement to a system I was perfectly happy with before the addition of the new component.

And so it goes with this hobby of ours.

kukur9's picture

Thank you, Steven, for being the nerd who uses all the various accoutrements and who has apparently tried the different combinations to hear what works. My journey has been similar, and I've even experienced additional gains by switching to a silver DC cable for my LPS-1, and using silver coax out of my Wyred 4 Sound Remedy. I mention this only because I found I preferred this combo over the USB input into my DAC which was mRendu to DAC. Now I wish I had tried my W4S Recovery between mRendu and DAC before I sold the mRendu!

Anyway, thanks for reporting on what tweaks yield the biggest gains. And in the future considering a comparision of alternatives as some other posters have suggested, because the net cost of new power supplies, cables, and devices add up (and your many tweaks are not cheap!). I, too, have found everything counts and sadly I cannot put an LPS-1 or equivalent power supply on every device I have in my computing chain and put Synergistic cords on everything in my audio playback chain, etc. (But truly I am glad you do!)

It would be nice to hear opinions about whether or not all this USB and Ethernet fuss can be obviated by a good Melco or SimAudio or Aurender alone. In the meantime, these devices and cables and power supples make my office and smaller systems sound..."mahvelous dahling!"

Thanks again.

BJameson's picture

"Blew me away" are the same words several expressed when the Intona was added between the sMS-200 and the DAC. How does tX-USBultra compares to Intona? Both blew everybody away.

tX-USBultra is over 3x the price of Intona so it will be great if the SQ can somehow be quantified between the two.

Thanks for the review.

Steven Plaskin's picture

I revisited the Intona in my SOtM sMS-200 review. It didn't sound that great with the Ayre QX-5 Twenty DAC and the sMS-200. A different DAC could change the results.

tjencks's picture

So first off multi-hundred dollar ethernet and USB cables are pretty nuts. I just can't understand the difference in using a $500 dollar cable and a CAT6/7 legit ethernet cable ... both are using TCP/IP protocol to transmit data in packets...if these packets all arrive intact I fail to see how there could be a difference.

Now the regeneration of clock for USB audio I buy to an extent...but wouldnt' a good DAC just reclock this data regardless of how it is received ?

To me the real deal here involves isolation from all sorts of nasty HF noise a PC generates ...

Why not use an USB to optical converter ... such as this:

I guess one could say that the receiving box still contains processing / creates HF noise...but seriously...some of the claims about this stuff are just hard for a technical mind to grasp.