Computer audio is a cool thing. Most people who switch to a PC or Mac based system always tell me how much music they did not know that they have. So browsing your collection can be an eye- and an ear opener for the many music lovers among us these days.
But the sound quality is not always what people brag about, some tell me of hard, edgy sound, not always associated with HiEnd audio. And as a result thereof big money often can be spent on USB and Ethernet cables, some nice clean power, and not to mention streaming devices or the software itself. Some (very good sounding) software can cost approx. 650 USD.
But why is it that Computer Audio has some weaknesses? The inside of every computer is not designed for that kind of amusement, but to do a whole bunch of tasks simultaneously - and as quick as possible. The power supply and the different boards and chips all add RFI and EMI noise to the system and together with bad impedance mis-matching it is not the best environment for a good sounding computer. Some HiFi lovers try to bypass the most noisy parts of their Mac/PC, and use it solely as a music player. Still there is lots of processing going on under the hood, and the noise travels from you computer to your DAC.
Now there are several manufacturers who address some of these problems. From Holland we have seen the VBus Isolator (https://www.sbooster.com/sbooster-tweaks/sbooster-vbus-isolator)
and from the USA Audioquest have come up with their Jitterbug: link.
On their white-paper (below) they explain more in depth how and why they do what they do. But the short version is, that the small USB REGEN that we have for this review, works like a kind of Hub, but it also separates the 5V power from the music, and last but certainly not least it REGENerates the signal (not just reclocking it), hence the name. The supplied power supply provides a clean and stable power, and together with the low jitter clock the result has low noise and low jitter.
The small unit is to be connected near your DAC, and is really just plug and play. The power supply is a switch mode type (22 watt/7.5V/2.93A), of course you can use a linear PSU if you prefer. Later this year UpTone Audio will come up with an even better power supply, and they give you a four years warranty if something goes wrong.
If you are curious if your DAC can benefit from the REGEN, our friends at Computeraudiophile.com have a long thread about their findings. Lots of DAC's are mentioned. Maybe yours too? Link: here
UpTone´s brilliant mind John Swenson explains a little more: link
When I read the threads at Computeraudiophile, some people say that there are no measurements that provide enough information that the REGEN actually works. To these people I can only tell, please use your ears, and then judge for yourself.
"Not everything that counts can be measured. Not everything that can be measured counts" says Albert Einstein. So maybe are we just not good or creative enough to find new ways of documenting scientific stuff? It's the same saying when speaking to no-believers of digital cables. It's only zeroes and ones, they say. And they are wrong, it's electrical current and power going through a digital cable, and the same goes for the REGEN. Enough said, order one of these, listen with an open mind and return it if you can't hear an instant improvement. I am definitely NOT sending this review unit back.
And speaking of return policy, UpTone Audio has a 30 days money back guarantee, so you can try before buy. Alex Crespi kindly informs us that that with more than 2000 units sold, less then 10 of them was returned because “they did not hear a substantial enough difference.”
And Alex Crespi also writes in an e mail:
“As for sample rates, the sky is the limit. Whatever USB2.0 and the person's DAC and drivers will support. The REGEN simply functions as a very high-quality, single-port USB hub and produces a new USB signal right at the input of your DAC. It really does not know that it is audio data. You could use it between a computer and hard drive or printer.”
Music is all around
But how does it sound. And what does it do to your precious music system?
Place it as close to your DAC as possible, preferably direct into the USB B input. Turn on the power, then your music system and use it just as always. In my Mac based setup it really was plug and play, and not F... and Pray ;)
“Tous Ces Combats” with the fabulous Myléne Farmer is a nice example of what the REGEN does. Her beautiful voice can sound a bit edgy and hard without the small REGEN. Try to listen with, and then without, the hard sibilants are clearly audible, and are NOT nice to listen to. The strings are more dominant without the USB REGEN, but also more hard. They are clearly more beautiful rendered with the REGEN inserted.
“Almost Like The Blues” with Leonard Cohen gives you shivers, without the small UpTone device the music does not touch you the same way. Cohens deeeep voice is so powerful, dominant yet soft. And yes, I listen with my feelings and not with my analytical part of the brain sometimes - which is what this hobby should be about, should it not? Evoke feelings, touch your emotions. And if a DAC, Amp, cable or whatever can do exactly that to me, it stays in my system, regardless of price or looks.
My phone rang, I took the call, and forgot all about my swapping the REGEN in and out of my system. I suddenly heard some hardness that I had not noticed before, ROON was randomly picking the very old song: “The Loco-Motion” with Carole King. Ok, I thought it is an old recording, so maybe that´s why it sounds hard to my ears. But when I wanted to remove the REGEN, it already was removed (by me of course, I just forgot that because of my phone call). Back with the REGEN into the DAC, and the hardness was not totally gone, but the song was now listenable.
One of my HiFi colleagues in the industry told me about Dan Fogelbergs song “Tucson, Arizona”. Though I´d never heard of the guy or the song I quickly fired up ROON, and played this beautiful song a couple of times. Why on earth have I not heard about this singer/songwriter before now? Anyway, the music just flows beautifully.
“You Take My Breath Away” with Queen starts in a capella, followed by a piano part, both sounds fabulous with the REGEN - without it it's just not worth to listen to. The sound is just hard, edgy and like a black and white picture compared to a HD movie.
One of this centuries greatest voices belongs to the Dane Isam B. Though also known for his great vocal works with the band Outlandish, he also gives me shivers down my spine with this his track “Undone (Change Will Come)” from the album Help Gaza Today. His voice is just wonderful. I plug out the REGEN and the sound in a second is one dimensional, hard and not beautiful at all anymore. And you don´t need endless listening hours, just listen to a track, pause it, take out/in the REGEN and its VERY clear that the sound has changed. Hopefully to something better and one that better suits your taste.
From last months long awaited album from David Gilmours Rattle That Lock we listened to the title track. And we where set back in time to some old Pink Floyd tracks, just with a different sound quality. Not better, not worse, just different. 2 minutes into the song there is a vocal choir with some lovely percussion details in the background. The Uh and Ah from the choir was way better to follow and softer to listen to, with at much more believable soundstage with UpTones small device. Oh, and I just forget to write more notes, the next song from the same album took over, and the piano at first, the acoustic guitar followed by Gilmours lead vocal took me back to a trip (no, sorry, not THAT kind of trip:=) long ago when enjoying his vocal, guitar and songwriting for the first time. And his Stratocaster just cried again... With the UpTone device, the sound was (I know, I am repeating myself) just more like... music!
Danish Bo Stief Dream Machine's album Heart&Destiny, where the slide guitar of Poul Halberg does some real magic on the track “Heart”, is another song that every HiFi manufacturer should put on demo. There are lots of fine percussion details, deep bass lines, and this wonderful guitar on top of it all. Just beautiful! On this track the REGEN really shines, the sound stage is much deeper, wider, softer and yet more precise. And way more entertaining if I may use that word again. Love-able could also be a good phrase to describe what the REGEN does.
“Appalachia Waltz” composed by Mark O´Connor and performed by Yo-Yo Ma shows how more likable the sound-stage gets with the UpTone device in the chain. The beauty of the song is totally removed together with removing the small REGEN. Strange but true!
Yasmine Hamdans song “Mediya" from her 2013 album Ya Nass can be a tough one for many not so well designed music systems. If her voice or the aggressive hi-hat gets to much digital harshness, or the low frequencies attacks to many standing waves, then you definitely have to do a thing or two about your room, your cabling or just invest in this little gem we have for this review! And yes the album is compressed, but not over compressed, if it was to heavy comped then it would be a no go to listen to - with or without the UpTone device.
Another song that can give me the shivers, is “Stimela" (The Coal Train) performed by Hugh Masekela. And yes, you can also enjoy music from the web. The sound of with/without the REGEN is clearly audible also when listening to YouTube videos like this one:
So if you stream from the internet, Tidal, ROON or whatever, as long as the REGEN is just in front of your DAC, the sound definitely benefits from it.
“Let It Rain” performed by Patricia Barber is my next example. I have that track in a 88.2/24 version. Oh boy, this is good, fab, cool… “can't you make that liquid fly, bubbles rise, heatwave die, that water slip and slide me away” she sings, right here in my listening room!
Is the sound with the REGEN more precise and do you get more bass or treble for your money? Yes, but what´s that draws me is the entertainment factor, it's just more fun, more enjoyable to listen to music with the REGEN then without it. No listening fatigue anymore, you can listen for hours and hours. And that's what it's all about, isn't my friends?
Thanks for reading and happy listening! I´ll get back to my music system right now. Can´t wait to REGENerate more of my lovely music.
Two guys are running UpTone Audio, John Swenson and Alex Crespi. Before joining forces at UpTone Crespi was the co-founder of Hovland Company (anybody remember the Hovland HP-100 and HP-200 pre-amps, and the RADIA, Stratos and Sapphire power amps)?, worked in computers at an early stage, and later on selling MusiCap capacitors.
Swenson at the age of five got hooked to music and electronics, and got an interest in digital audio at an early stage. He also has a good reference, as he is singing in choirs and does live sound mixing and recording.
Furthermore his day job for more then 30 years is as senior engineer for a large computer chip design firm, where he is in charge of optimizing the power distribution networks deep inside giant processor chips - the sort used in the high-speed network switches in data centers.
And here is the white paper from UpTone Audio:
UpTone Audio — USB REGEN explanation. August 2, 2015
To explain how the UpTone Audio USB REGEN works and why it is so effective with such a wide range of USB input DACs, we first need to define some technical terms and some problems inherent in USB audio interfaces—hopefully in not-too-technical language:
PHY: PHY is an abbreviation for the electronics that interface to the physical bus. PHYs exist in most every type of data interface (Ethernet, FireWire, optical, etc.) A USB PHY serves two primary functions: to convert the analog voltages used on the Data-plus and Data-minus wires into a digital format normal logic can understand, and convert the high speed one-bit-at-a-time serial data stream into a slower parallel set of wires to be sent to the USB protocol engine (XMOS processor, FPGA with USB core, etc.). The lowly PHY chip is actually a tremendously noisy and complicated device containing several PLLs and clocking at various phases—and there is no such thing as an optimized-for-audio PHY. The PHY part of a DAC’s USB is highly susceptible to the condition of the USB signal, its "Signal Integrity" (SI).
SIGNAL INTEGRITY: A high-speed USB signal runs at 480 mega bits per second, which is fairly high. SI is comprised of the rise/fall times of the signal edges, amplitude of the signal, noise sitting on top of the signal and jitter of the edges. Variations in any or all of these can decrease the SI. The computer determines this initially, and then it can get significantly degraded by running through cables and connectors.
The decrease in SI can be so large that it becomes difficult for the PHY to determine the actual bits. Thus the PHY contains several methods used to pre-process the analog signals in order to make it easier to determine the bits. When the SI is very good, the PHY can turn off the pre-processing steps and easily determine the bits. As the SI degrades the PHY turns on different parts of the pre-processing as needed. Each of these steps takes a fair amount of power to operate, thus creating noise on the power and ground planes. The more processing the PHY needs to use to determine the bits, the more noise is generated. Thus part of the packet noise is directly related to the signal integrity of the incoming signal. The higher the SI, the lower the noise.
PACKET NOISE: In a DAC the data packets coming in on the USB bus are not continuous—there is significant time in-between each packet. Thus the processing of these packets produces noise on the power supply and ground plane that come in bursts, and we refer to this as "packet noise". Since the rate of USB packets is 8KHz there are strong components of this noise in the audio band. This noise can cause jitter in clock oscillators, re-clocking flops, and DAC chips. It can also go directly into noise on the output of DAC chips.
Part of this noise is determined by the USB protocol engine (chip after the PHY) and is going to be constant for a particular DAC.
POWER DELIVERY NETWORK (PDN): In order for a power supply to properly respond to instantaneous load variations, it needs to have a low impedance over a very broad range of frequencies. For digital audio this is from low Hz to hundreds of Mhz range. The entire supply flow from mains AC to board layout and capacitors on the board play a role in getting this right. The process of frequency optimizing the PDN is something that is done in expensive high-speed network equipment, but is almost never done in consumer products, especially audio equipment. (And our experience with the REGEN points to this being quite important for digital audio.)
Okay, now that some definitions and issues have been set forth, let’s look at how the UpTone Audio USB REGEN addresses them.
To recap the issue:
The lower the signal integrity (SI), the harder the PHY has to work, which produces greater packet noise. If the SI is very good, the packet noise from the PHY is less than that from the protocol engine. As the SI degrades the packet noise from the PHY can dominate.
Again, the packet noise consists of two parts: noise from the USB protocol engine and from the USB PHY. The protocol engine noise does not depend on the input signal quality, just the data, so its impact is always going to be the same no matter what is done with the input. The PHY is the part that actually connects to the electrical signals on the bus, ITS contribution to packet noise IS dependent on the quality of the input signal.
It is very important to keep in mind that all this is what happens INSIDE the DAC by its own operation, it is NOT noise on the USB bus that is somehow getting into the DAC as is commonly thought.
At this point there aren't any DACs that have been specifically optimizing their USB inputs for SI and impedance match, it's too new as a specific concept to design to. But the best DACs do optimize this to some degree, whether by trial and listening or as a by- product of optimizing for something else.
So tell us how the darn thing works already!:
The REGEN is at its core a single-port USB 2.0 hub. All hubs actually contain two USB interfaces and a full-blown USB protocol engine. It is not just working at the analog level, it is actually receiving the data from the DAC, putting it in a buffer and retransmitting (and the other way for the packets from the DAC).
It uses a selected USB hub chip to create a new USB stream to deliver a very high signal integrity to the DAC's USB PHY, thus decreasing the PHY’s contribution to packet noise. It is called “REGEN” since it completely REGENerates the data signals that cables are messing up—it’s not just a re-clocking. Because it uses clean power and a low jitter clock, the output of the hub has low noise and low jitter. To be most effective, and to maintain best signal integrity and ideal impedance matching it is best positioned right at the input to the DAC, thus its small size, low weight, and included male>male USB ‘A’>’B’ adaptor. The result is that the PHY in the DAC doesn't have to use any of its pre-processing circuit arsenal so the packet noise is as low as it is going to get.
Does the REGEN eliminate the need for a good USB cable and other computer optimizations?:
No. The hub chip inside the REGEN has its own PHYs and protocol engine, which themselves generate packet noise on ITS power and ground planes. So the REGEN itself is also sensitive to the SI of the signal fed to it, which is why good USB cables and specialty USB host boards feeding it still make a difference—maybe just not as much.
A lot of time was spent on the design and board layout to minimize this packet noise but it is still there. The impedance of the "Power Delivery Network" (PDN) over a broad range of frequencies determines the amplitude of the packet noise produced by the hub chip. The REGEN’s frequency optimized PDN is what makes is such a good sounding source.
The ideal solution would be to figure out how to prevent all this noise from crossing out of the USB input system and getting into the DAC chip and clock. Unfortunately this is really tough and nobody has completely figured out yet how to do so. Thus every DAC ever built will have some level of susceptibility to external influences, some more some less.
The question everybody asks then is:
Well what about DACs that have full galvanic isolation after the USB system and re- clocking on the DAC side? Unfortunately USB input noise of all sorts still makes it through to some extent and reaches the DAC master clock. Exactly how this works is complicated, John Swenson has written in-depth about this elsewhere The upshot is that neither galvanic isolation nor re-clocking completely get rid of it. They help attenuate it some, but don't get rid of it.
The REGEN’s secondary function is to ignore the 5V USB bus power coming down the cable from the computer (or other host) and to provide—to DACs that require it—a very clean and isolated 5V supply. The REGEN has a separate ultra-low-noise regulator for this. (For DACs that don't use the 5V wire, that regulator in the REGEN is not used for anything.)
Lastly (unlike another hub-chip based device out there), the UpTone REGEN uses a 4- layer board, primarily to allow a proper impedance match. With a standard thickness 2- layer board it is impossible to attain a proper impedance match to the hub chip. The pins on the chip are small and close together, this necessitates very thin board traces. With a two layer board the distance between ground plane and these traces (this is called a differential micro-strip configuration) produce an impedance that is much greater than the spec. With a 4-layer board the ground plane can be much closer to the top layer, and that allows for appropriate impedance with the very narrow traces. The REGEN also uses surface-mount USB jacks that allow for appropriate trace width and spacing to continue the impedance matching through to the USB jacks. The result of this is that there will be very minimal reflections at the REGEN side. Even if the DAC does not have good impedance matching—which is pretty common and which WILL cause a reflection at the DAC end—it will be absorbed at the REGEN because of the proper impedance matching.
©Kurt Lassen 2015
UpTone Audio USB REGEN™
Price: USD 175