Digital Processor Reviews

UpTone Audio's USB Regen is a powered, single-port USB 2.0 hub that takes the USB signal from your computer, regenerates (ie, reclocks) the data, provides cleaned-up 5V power from a built-in, ultra–low-noise regulator, and sends an impedance-matched signal to your DAC. The Regen is designed to sit as close to your DAC as possible; UpTone supplies a male/male USB A/B adapter—a solid, double-ended plug, which they recommend over the 6"-long male/male USB A/B cable they also provide.

At one end of the Regen's small (2.2" wide by 0.7" high by 1.8" deep) case of black-anodized aluminum is a USB Type-B port for connecting the USB cable from your computer, and a 5.5 by 2.1mm barrel jack for the included supply. At the output end is a USB Type-A port for use with the adapter plug mentioned above. An amber-colored LED indicates the power status.

UpTone talks about four main issues the Regen is designed to address: PHY noise, signal integrity, packet noise, and "frequency optimizing" of the power-delivery network. Again, each of these pertains to noise inside the DAC that could pollute the analog signal.

Listening
I began my listening sessions with my reference Auralic Vega DAC). The rest of the system comprised a Pass Labs INT-30A integrated amplifier and DeVore Fidelity The Nines speakers.

I listened for a few weeks with the Regen in, then took it out. Wow: not subtle. Absent the Regen, it was as if my music had just come back from a week at weight-loss camp: Everything had less body and weight, and the overall spatial sound picture was reduced in every dimension. On a scale of sonic difference of 1 to 100, with the greatest difference possible in a hi-fi system's sound being 100, the Regen was a solid 15.

The Regen also offered a less brittle, less "digital" sound. Subtle, beautiful music, such as Washington Phillips's What Are They Doing in Heaven Today? (44.1kHz file from Little Axe Records), sounded more heavenly, and it was easier to tell János Starker's cello from Yo-Yo Ma's—I'm talking improvements that made listening to music more enjoyable and more meaningful.

It's important to note that the Regen didn't change the sonic character of whatever DAC was in use; rather, they enhanced its qualities.

I also ran these comparisons with a LampizatOr Lite 7 tubed DSD DAC replacing the Auralic Vega, as well as in my desktop system: an Audeze Deckard DAC–headphone amp driving ADAM A3X speakers and Audeze LCD-X headphones. All of the changes I heard with the ReGen through the Vega I also heard through the LampizatOr; while the AudioQuest JitterBug and Schiit Wyrd offered some improvement, the Regen consistently bettered both in terms of overall improvement. But on my desktop, the improvements gained with all three devices were less noticeable, especially in terms of spatial performance: My desktop setup is very much a nearfield listening experience, in which images and reproduced spaces are smaller and more intimate. The same held true for listening through headphones, as images were not reproduced in free space. With this in mind, if I were to pick for this system one such device, it would be a single JitterBug: The additional improvements offered by the more expensive ReGen didn't strike me as worth the extra cost.

Summing Up
If you want to try only one of these USB devices, I recommend UpTone's USB Regen as the performance choice, and AudioQuest's JitterBug as the budget choice. If your big rig is very resolving and subtle improvements grab your attention, I recommend the Regen-JitterBug combo for a more bewitching experience.—Michael Lavorgna

Kalman Rubinson on the USB Regen
In the last installment of "Music in the Round," I introduced the miniDSP U-DAC8 ($299), an eight-channel USB DAC at 1/10 the price of its nearest competitor—great news for anyone wanting to start playing multichannel files. Enhancing the sound with Dirac Live toned down the glint in the treble but didn't help the swimming instability in the soundstage. It was as if the balance was shifting under my feet (and before my ears)—the effect was most pronounced in the surround channels. Because it's obviously built to a price, the U-DAC8 would be a likely candidate for some of the many devices offered to improve USB transmission or power supply; of the several such things I looked into, the first to arrive was UpTone Audio's USB Regen ($175).

The Regen is basically a USB repeater that uses the digital datastream from your source to generate an entirely new USB signal to send to your DAC. Inside it is a USB hub chip supported by low-noise voltage regulators and a low-jitter clock. The Regen has its own power supply, which UpTone says is "the best spec'ed and sounding 22 watt/7.5V/2.93A (overkill) tabletop (93 x 54 x 36mm) world-voltage-compatible SMPS we could find." The 5V from this supply feeds pin 1 of the output USB and replaces the 5V bus from the incoming USB. The Regen's USB plug is meant to be inserted into the DAC's input via a short (ca 3"), stiff, male-male adapter plug, to eliminate any variables due to a longer input USB cable. If you can't fit the Regen into your system that way, a 6" cable is also provided. UpTone says that the Regen should be transparent to your source. I inserted it between my Mac mini (running Windows 7 via Apple's Boot Camp) and the U-DAC8; setup required only a computer reboot and reselection of the U-DAC8 as the output.

It was as if the Regen weren't there—until I began listening closely. The fundamental quality of the sound was better. All hints of the abiding brightness were eliminated and, as a result, the frequency balance was smooth and unaccented. The bass, with or without Dirac Live, was firmer. However, the biggest change was in image balance and stability. My sensitivity to such flaws increases with volume level, and I realized that I'd tended to play music at lower levels with the U-DAC8 to avoid being distracted by the surround-channel signals, whether discrete or just ambient. For example, the 24-bit/96kHz, 5.1-channel FLAC file of Willie Nelson's Night and Day (DVD-A, Surrounded-By SBE-1001-9) has instruments discretely positioned at and between the speakers. Without the Regen, those instruments whose images appeared between speakers seemed more vaguely positioned; with the Regen, they were rock stable. Through the Regen, I listened to another favorite: Manfred Honeck and the Pittsburgh Symphony's recording of Dvorák's Symphony 8 (SACD/CD, Reference fresh! FR-710SACD). Now I could turn up the volume to live-concert level without suffering any queasiness due to uncertain ambience.

If it could work the same magic with higher-priced DACs such as my exaSound e28, the UpTone USB Regen, at $175, would qualify as a logical addition. But I don't yet know, because I lent the e28 to JA. A $175 accessory for a $299 DAC might seem inappropriate, but I think it's a bargain. Think of it as creating, for less than $500, an eight-channel DAC whose sound is comparable to that of two-channel DACs for the same price or more.—Kalman Rubinson