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Allo USBridge Signature Review

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The DigiOne Signature Board’s most notable feature is its support for S/PDIF connections. This is nice to have but not mandatory unless your DAC sports a S/PDIF connector but no USB input. I have several devices meeting the criteria so it is always something for me to evaluate gear in as many ways possible, but most of our readers tell me their DACs are USB only and for them S/PDIF is not a concern.

Fig.5 – Allo’s DigiOne SIG replete with all its connections

The Shanti LPS (Linear Power Supply) affords one the opportunity to power USBridge and DigiOne Signature boards separately off one power cord. The Shanti, though sizable and possibly a physical concern for those with space constraints, runs rather quietly, no buzzing, no humming. Allo implemented ground binding posts on the cases of the USBridge Signature as well as the Shanti and make the case really hard for running separate grounding connections including one’s DAC if possible.

There are numerous schools of thought here with respect to reducing radiated emissions and I pored over countless white papers on the topic, not to mention having contacted numerous network and sound engineers in my circle of friends. The jury remains out on what is actually audible/noticeable.

So, if you decide to go with the Shanti, essentially shell out the money, the cost of cables to ground the devices and DAC is relatively negligible, so it can’t hurt. As for the Shanti’s efficacy, it is not going to remedy sub-standard/faulty ROMEX wiring coming into one’s home. However, if the idea of LPS integration meets with favor and is seen/heard to make a positive impact upon the sonic quality, then by all means proceed.

The Shanti costs $159 and, rather than paraphrase Allo’s reasoning behind their cost-effective LPS, here is a link to their dedicated web page for the Shanti: Dual Linear Ultra Low Noise PSU:

Fig.6 – Allo’s Shanti LPS from above with its dimensions

Fig. 7 – Allo’s Shanti LPS backside, note the grounding post

Allo made the decision to employ the PI 3+ compute module in lieu of the stock Pi 3+. Hats off to them for doing so and opening up their solution to even more interface options. With the inclusion of the 40-pin interface connector the door is opened even wider to a flood of HAAT-based boards. As mentioned earlier I opted for the DigiOne Signature board with its S/PDIF, BNC and USB connectors.

Allo makes a point of its USBridge Signature being engineered to maximize isolation of both ethernet noise emanating/originating from the compute module as well as ensuring the cleanliness of the USB port to the DAC. Clean Power is also evidenced by the printing on their boards as seen below:

Fig. 8 – Allo takes clean power seriously

Note the printing on the bottom right corner of the board above.

I connected the USBridge Signature directly via ethernet to my home network sporting a 10GB synchronous connection. Honestly, I never thought I’d be able to say/type that as my very own actual bandwidth and keep a straight face. 20+ TB storage resides on a Synology NAS while my Roon Core(s) can be, at any time, an Intel i5 NUC, an Apple Mac Mini, or a Lenovo TinyPC.

The Allo USBridge Signature is agnostic that way, it just doesn’t’ care nor should it. Allo’s device worked flawlessly in every permutation I could conjure up. I cannot fault the device, regardless of which bundle of options is ordered up. I made a point of running the device in every possible configuration with and without the Shanti and with and without the DigiOne Signature board. And in every instance, it worked and continues to work without issue.

And yes, while one can connect the device wirelessly via Wi-Fi, I encourage you all, especially if this is to be used at home, to do what you can to make a direct wired connection between it and your network. Your smartphone and/or tablet can connect wirelessly — that’s separate from this. I implore the use of the wired ethernet connection because this past year so many gripes and complaints from readers and followers about their digital audio systems had far less to do with the audio and so much more with their home networks and how they were connected. Switching so many to a wired connection resolved so many of their concerns. So, if it is possible, if you can, if directly connecting an ethernet cable is not going to invoke flashbacks to the Labors of Heracles, by all means do so.

Fig. 9 – USBridge Signature backside.

Note not only the grounding post but the WIRED ETHERNET jack.

Fig. 10 – USBridge Sig case housing both boards. Note the SPDIF BNC and RCA connections, as well as the position of the ground pots, and the addition of the 5V CLEAN POWER connection

In the past there were concerns with the Linux kernel taking issue with DSD playback, so I made it a point to make sure my DSD library was at the ready. That was then, this is now and the files played cleanly, no stops and starts, and no drop-outs.

The cost breakdown for the bundle I worked with is as follows (do visit for all of their pricing, options, bundle configurations and specials from time to time):

  • USBridge Signature Board: $239
  • DIGIONE Signature Board: $239
  • Shanti Power Supply $159
  • Case housing both boards $23

There is no one correct way to configure and accessorize Allo’s USBridge Signature but I have run through a number of possibilities. You can go all out taking the deluxe route by assembling all the options or go basic. Either way if you’re in the market for a relatively affordable digital audio solution that delivers the goods both physically and sonically, look no further.

When I sat down numerous times to write this piece one of my colleagues asked,”Why don’t you write up a piece about all your other explorations? … all the other devices you chose not to review?? So, here’s some personal insight: I’m not that much of a masochist.

I have put 2019 behind me. It was a year of so many tech explorations, delving into numerous Sparky and Raspberry Pi-based solutions, and I’m done with it. All I can say now is that the highest praise I can bestow upon a product is that I use it day in and day out without fail. That is Allo’s USBridge Signature bundle with the DIGIONE Signature Board and Shanti LPS in a nutshell.


Copy editor: Dan Rubin


5 Responses to Allo USBridge Signature Review

  1. Dan Bonhomme says:

    I need specifics on sound quality and comparison to at least some competitor.

    • edward says:

      I have the AlloUSBridge and I compared it to normal Raspberrypi B 3+ and 4, all going USB out. The sound is not pleasing at all, rather thin sounding and non-engaging. Everything from the midrange down is lacking.

  2. Fredrik says:

    This review leaves the key element of an audio device review untouched. How does it perform, comparison against other products, benefits of using the tested power supply, sonic difference between Ethernet and wifi, etc.

  3. Daina Wilburn says:

    Thanks for this review. You are right, there are SO MANY options, that I frankly don’t even take that many looks at reviews anymore until something bad happens or happens enough times, that I decide I should take my head out of the dirt and look around. I’ve been streaming in some form or fashion since 1999, before any of this revolution, originally coming out of my sound card of my now monolithic looking PC with RCA cables. That’s pretty pre-historic. Since then I’ve tried at least one version of every technology that has come out. Pretty much! You should see my graveyard – aka closet. I stumbled onto the Squeezebox SB3 in 2006 and between then and now, it’s been a whirlwind. Loved my SB3, was sad to see Logitech buy it and essentially kill it. By 2015, resolution limitations on my SB3 had long relegated it to the bedroom, and after using many spidf solutions and software coming directly from PC, I stumbled onto the Raspberry Pi. I used the Pi’s with Volumio for a couple of years but with options for Logitech Media Server around, I liked the idea of all my devices running from the same core, so I moved the PC a step back and made it the server – so no NUC or network drive, just some kind of PC/Laptop/Tablet sitting off in a more convenient spot, with 4 TB hard drive connected. All running Logitech Media Server (LMS), throughout the house. In 2017 I found the Allo US Bridge. It’s been a love hate relationship. I use Diet Pi with it. One thing I have never liked about it is that when there is any ripple of an issue, it is the last to be back on line and usually requires a reboot. I’ve read that the Allo/Sparky software was pretty old and really needed to be updated. The other night, it went through ‘one of those things’ again. I’ve developed a real relationship with a tech support guy there, living in India, and he has always bailed me out. So I reached out. After trying everything I can could think of, as a last resort, I pulled the SD card out and re-inserted. But, now the network couldn’t find it at all. I rebooted a half dozen times more and finally, miraculously, it connected. I had a feeling we were back in business, but I didn’t test it. I went to bed and waited for my buddy Sudeep to reply. This time, no reply. So, the next day, I once again crossed my fingers and gave it a try. It’s working flawlessly again. Who knew? LOL. But I decided it was time to familiarize myself with options. My main system where by good gear resides is where all my issues reside. Those 2-3 other Pi’s just work. (My old SB3 finally died – sad day). So, I eventually looked at the Allo site and found your review. I think that going back to a Pi platform from a Sparky is probably a good idea and renews my interest. My current Allo is ethernet wired and I imagine I would continue with LMS. I’ve spent time with Roon, and although it is fabulous in many ways, I’ve spent over 20 years organizing my files in my own order – my own genres/artists/albums songs. And unfortunately Roon is just built in such a way that i cannot view my files the way I organized them, call it “native view”, and from talking to Tech Support, it’s not in the cards to give me that capability, so I’ll probably stay with LMS, but your review really gives me pause. I can see this as a fairly easy transition. When it works, which is really about 90 percent of the time, it is very good. I’ll run my current Allo down to the basement or something. So, thanks. Appreciate your review. As for some of the others needing for more info, I’ll just say the original Allo has sounded very clean, open and organized with all the DAC’s I’ve connected to it. I use both the gui and the command line stuff for the same reason you do. If this one has the same separation of and devices and power as the regular USBridge, I have no doubt the Signature will sound just as good, if not better.

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