Device Type: USB Regenerator
Input: USB Type B
Output: USB Type A
Dimensions: 57 x 46 x 18mm
Availability: Direct Online
Price: ISO REGEN $310 (no power supply), $325 (w/SMPS power supply), ISO REGEN/UltraCap LPS-1 Bundle $655

This is an article about a USB accessory. Just thought you should know. If you're looking for writing that illuminates the social and political forces that brought us to this particular moment in our culture, allow me to suggest Hannah Arendt's Eichmann in Jerusalem.

This, on the other hand, is about an aluminum object slightly larger than a box of Tic Tacs. The Uptone Audio ISO REGEN is inserted between your USB cable and your DAC's backside, and what it does, put simply, is regenerate and isolate the audio signal coming from your computer or server. If you're wondering why you might want to do such a thing, read on.

The ISO REGEN happens to be a follow-up to the well-received USB REGEN, introduced in 2015, which in its quiet way became a groundbreaking product. For much of computer audio's lifespan, the attention of both enthusiasts and engineers has been focused squarely on digital-to-analog conversion. The USB REGEN was one of the first products to address the probable crappiness of the digital data stream before it enters the DAC and, in a larger sense, its susceptibility not only to jitter but to electrical noise, power-supply variability, ground loops and other hazards. According to a once-popular line of thinking, prior to conversion the data stream is "just ones and zeros" and therefore immune to audible changes. This notion implies that we're dealing not with the transmission of complex electrical signals but a cheerful conga line of numbers dancing down a tube.

Today most of us know better. In the wake of the USB REGEN, newer devices demonstrated just how lame the "ones-and-zeros" argument is. Probably the most eye-opening among these have been Sonore's microRendu and ultraRendu—specialized audio computers with a credit-card sized footprint. They receive data via an Ethernet jack and turn out to be far better at playing music than many expensive one-box servers. Recently dozens of products—from ifi, SOtM, PS Audio, Wyred4Sound, and others—have appeared with the aim of preserving the integrity of the "upstream" signal. Some resourceful enthusiasts have even pressed items designed for other tasks into this job—like fiber media converters (FMCs) that route the audio signal through a length of fiber optic cable.

The reason any of this might be worth writing about is that the sonic and musical improvements offered by these upstream devices turn out, in many cases, to be surprisingly substantial, and often larger than those obtainable by swapping DACs. Many seem to play well together and offer cumulative improvements, poking a hole in some manufacturers' claims that their newest widget offers "total rejection of jitter" or "complete galvanic isolation." All this suggests that much of the glassy, unemotional sound heard from many digital sources is caused by hijinks happening upstream of the DAC. And it reminds us how much we still have left to learn about music reproduction using ol' ones and zeros.

But let's get back to the ISO REGEN. (From now on I will refer to it as IR; I hate typing all those caps.) Its functionality is described in fine-grained detail on Uptone Audio's website. In brief, it differs from its predecessor by offering upgraded components, including spiffier regulators and clock, and adding galvanic isolation in the form of a new chip from Silanna Semiconductor, which can be switched on and off.

I had my USB REGEN on hand to compare to its newfangled progeny. To get this out of the way, it was no comparison. The IR didn't exactly beat the UR to death with a ball-peen hammer, but the differences weren't subtle. The IR made every track sound more tactile, more colorful, and less edgy than its predecessor. I thought it sounded quieter, too, but after a lifetime of playing my headphones too loud, I might've imagined this.

I had a chance to try the IR with several power supplies (units from SOtM, Vinnie Rossi, and Uptone's own UltraCap LPS-1) and while they all sounded different, they all trounced the "Mean Well" switching power supply included in the package, which looks like a fancy wall-wart. When considering the value of the $325 IR, factor in the cost of a high-quality external power supply. Without one, you won't hear what the unit was designed to do. On the other hand, the IR comes with a short, rigid USB adapter meant to connect it to your DAC; to my ears this noodley connector sounded better than any USB cable I had on hand, even several expensive ones. And, in terms of dollars, it's as free as a bald eagle.

I first listened to the IR with both the SOtM sMS-200ultra and the Sonore ultraRendu, both configured as Roon endpoints, and my Holo Spring Level 2 DAC. After weeks of listening, I'd say that the latest SOtM components excel at detail retrieval and silent backgrounds, whereas the Sonore streamers focus on making music preen and strut. Though both sound excellent, I tend to prefer musical thrills to sonic ones, and for pleasure I listened more often to the ultraRendu.

With the SOtM streamer, the IR had the effect of humanizing and relaxing its sound, something I always enjoyed. Even after adding into the mix SOtM's tX-USBultra signal regenerator—a product with similar functionality to the IR that costs nearly four times as much—I found that leaving the IR plugged into the DAC made a positive difference, adding a dash of richness and ease to the sound. I was about to try the IR with the Sonore ultraRendu when Uptone's Alex Crespi told me that he thought the pairing was "inappropriate," given that the ultraRendu already includes some of the IR's functionality.

Allow me to respectfully disagree. One of my favorite things about Roon is the way Roon Radio forces me to constantly rediscover the music on my hard-drive. After I listened to some beloved mid-1970s tracks by Merle Haggard, Roon routed me to a Willie Nelson record from 2010 called Country Music—(the title is a winking acknowledgement that Nelson hadn’t recorded country music in years)—which turned out to be really fun. With the ultraRendu alone, "Pistol Packin' Mama" sounded engaging, bouncy, cavernous and unrestrained, but had a distracting steely edge. The cast-aluminum sectional horns in my 1967 Altec Valencias can sound steely and unforgiving at times, and I assumed that's what I was hearing. But after adding the IR (powered by the LPS-1) the edge melted away, making Nelson's reedy tenor and acoustic guitar sound sprightly, vivid and utterly, superbly enjoyable.

Alex Crespi suggested that the optimal application for the IR is in a simpler system, so I fired up Tidal in my MacBook Air and connected it via a USB cable to the Holo Spring. Compared to the previous setup, streamin' Willie and his band sounded smaller, flatter, less colorful and less dynamic—in fact, the track sounded pretty rough. Adding the IR and LPS-1 improved things in every regard, restoring a measure of color, coherence and dimension to the music (but of course it sounded nowhere near as convincing as with the previous playback chain). How big a measure? That's difficult to quantify, but if new speakers might improve the sound of your hi-fi by 50%, I'd peg the IR at 8%. In my system, it made a more unambiguous improvement to my musical enjoyment than any digital cable or accessory I've tried.

The comparison led me to observe that analog and digital media differ in the way they respond to noise, distortion and other degradation. With analog, the edges of the music become muddy and indistinct—think of a second-generation cassette. With digital, the edges are preserved but the music is bleached of color, presence, texture, dimension and the subtle timing cues that makes it propulsive and coherent—think of a severely-compressed MP3. Which one is worse depends on your preferences.

Using the IR proved mostly uneventful, except for a few instances when it stopped working mid-track, turning the information display on my DAC blank. Alex Crespi suggested this was the result of inadequate grounding and suggested I run a wire between the IR's USB output and the grounding terminal of my Shindo Aurieges preamp. I didn't try this because I didn't have to—for some reason, installing two FMCs and a length of fiber-optic cable between the sonicTransporter and the ultraRendu solved the problem.

I suppose this is a roundabout way of telling you that the Uptone Audio ISO REGEN is pretty sweet. With every permutation of components, it made my favorite music more engaging; not once did it make it sound worse. It works well in both complex and simple systems. It represents resourceful, original engineering. And even with the need for a decent power supply, it strikes me as excellent value. This tiny aluminum box won’t change your life, but it may help illuminate the music you love.

headdoc's picture

...that this is the first audio equipment review I have come across that references the Nuremberg trials. Well done, sir.

headdoc's picture

...Nazi war criminals, as the title would clearly indicate Arendt was reporting on something else.

DC_ Bruce's picture

Adolf Eichmann, a Nazi war criminal fled Germany and went into hiding after WW2. He was not tried at Nuremberg. Nazi-hunters eventually found him, and he was tried elsewhere, if memory serves.

headdoc's picture

Jerusalem, according to the book title, and history. I caught the error, but don't know how to edit posts.

thyname's picture

Great review as always!

Since you already reviewed the SOtM Tx-USBultra earlier, how doe the IR compare with it?

Alex Halberstadt's picture

Thanks for the kind words. Steven Plaskin reviewed the tX-USBultra. I find devices like the these to be more system-dependent than most. In my system, the tX-USBultra made a bigger sonic difference, whereas the ISO REGEN made a bigger musical difference. Hope that makes sense.

DC_ Bruce's picture

I have no doubt of the accuracy of everything you report. But, it just adds to the discouragement of someone like I am who's wanting to bring his digital audio into the 21st century. This whole population of NAS's, renderers, network players, DACs, little interface devices (along with their power supplies that cost as much as the device itself) and software with odd names like "Roon" "JRiver" and so on is kind of daunting. Its enough to send me back to my shiny discs, flawed though they may be! :-)
[Sorry, just had to get that off my chest; and it's no fault of yours.]

headdoc's picture

I agree that this world seems daunting. I am looking into Bluesound, which may not be high end, but has an update path involving NAD and the speakers of one's choice.

Alex Halberstadt's picture

I share your frustration. It can be a lot of devices to keep track of. But the good news is that you can start with a simple system and grow it along with your curiosity and budget.

Brown Sound's picture

I have watched this fun branch of the audio hobby (and this site for that matter) become filled with mega-buck specialty PCs (streamers). These expensive boxes may sound fantastic and are easier to setup/install but they kill the fun. Some of us like the idea of tinkering with "NASs, renderers, network players, DACs, little interface devices". I just finished getting a rebuilt Linux Mint laptop setup with WINE and foobar2000 to work across my network to a server and output properly to an Audioquest DragonFly 1.0. It was a friggin' blast!
Sadly, this branch of the hobby, while it still has plenty of budget items, has become awash with these easy to use PCs. Computer audio is supposed to be a bit mysterious and a little challenging to configure, in my opinion. Unfortunately, it and this site have slowly (notice I said slowly Michael, because I have been here since it started) changed into something for folks with a lot of disposable income and no desire to be challenged. I have been a subscriber to Stereophile for almost thirty years and to both High Fidelity and Stereo Review for the ten before that, so I love reading about gear, both budget and expensive. But a lot of it is what I call 'audio porn', because on my technician salary, it ain't happenin'. It seems like more and more of the computer audio products are sliding into that 'audio porn' area and that, Michael, was not the Audiostream blog I signed up for all those years ago.
[Sorry to ramble on, but I just find it disheartening to have the one part of the audio hobby, that I really enjoyed to be brushed aside for some rich guys with no technical skills. Just my opinion, of course.]

Brown Sound's picture

The new PS Audio Stellar Gain Cell DAC, the guys at Innerfidelity just reviewed seems very sweet. I would love to hear Audiostream's angle.

Brown Sound's picture

Great review, Alex! How do you think the Regens compare to a AQ Jitterbug?

Brown Sound's picture

I just saw that Steve compared them two years ago, but I would still like your opinion. Thanks.

Alex Halberstadt's picture

I like the Jitterbug, but the ISO REGEN does a lot more in my system. It's also more versatile, since there are some application where the Jitterbug is too much of a good thing. Then again, given its price, the Jitterbug is insane value.

AllanMarcus's picture

You reviews of all these de-crapifiers is great. Thanks.

Can you please review the Schiit Eitr? Form what I've been reading, this is the device to get for USB from the computer audio.

tacitus's picture

Will this device help with other music servers other than a pc? E.g. I have an Aurender X100L which I am feeding into the new Chord QuTest dac. Do you think that putting the Regen in between would provide any sound quality benefits or is it just a case of adding another item into the chain which might actually worsen things? I am really curious how these pc add-ons combined with Roon, etc compare in both sound quality and useability (Aurender is just so convenient to use) to a music server like the Aurender. Is it worth the journey and cost?