Allo DigiOne Signature Review

Tyler Schrank’s original DigiOne Player review appeared on our sister site InnerFidelity, but in the end, I felt this type of review is far better suited for our readers here at AudioStream who seem to have more of a bent towards digital source types.

While in some ways I’m digital-connector agnostic, (whatever sounds best and that varies component-to-component in my experience) SPDIF (Sony/Philips Digital Interface) is at the lower-end of my personal preferences because of it’s inherent cap on file resolution (20/96 PCM or 24/196 depending on implementation and no DSD UNLESS the SPDIF implementation takes a page from the dCS playbook on DoP (DSD over PCM). This involves collating subsets of “16 adjacent 1-bit samples from a DSD stream and packing them into the lower 16 bits of a 24/176.4 data stream … A specific marker code in the top 8 bits identifies the data stream as DoP, rather than PCM) so for practical reasons when it comes to reviewing, I tend almost exclusively towards USB and Ethernet to get my ones and zeros delivered unmolested in every form to my DAC of choice.

As with all things audiophile. YMMV.

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Now, on to the review! Take it away Tyler…

As I would expect with my usual luck, Allo’s upgrade to the DigiOne Player, the DigiOne Signature Player, became available for sale shortly after I purchased the original and wrote a review for it HERE. I should have realized there had already been rumblings and basic announcements posted for the device across a few forums, so I had already fallen behind. Allo is rolling out new and as best as I can tell, high quality products on an aggressive timeline, so I’d recommend keeping tabs on them if you want to stay ahead of the curve.

Luck struck the other way, though, when Allo’s Andre Strul reached out regarding my DigiOne Player review and asked if I’d like to review a loaner sample of the new Signature Player. Given how excited as I was with the original, given its excellent performance, I couldn’t miss out on the opportunity to give the Signature a shot.

Signature Upgraded Tech Specs

The DigiOne Signature Player’s hardware improvements on paper offered a meaningful upgrade over the original, intriguing my engineering side and fuelling my curiosity of what subjective listening improvements they would bring to the table.

(If you’re unfamiliar with the full nature of these Raspberry Pi + HAT (Hardware Attached on Top) devices, I suggest you read through my previous review and some of the follow up comments to get a better idea.)

Functionally, the Signature is mostly identical to that of the original DigiOne Player. From a usability standpoint, the biggest difference is that you’ll need two power supplies for the Signature. The reason for this is simple: separating the dirtier power feeding the Raspberry Pi from the SPDIF output card that sits on top. If you’ve seen anyone with a custom music server that utilizes a separate, cleaner power supply for a USB PCIe card, the idea is similar.

For a relatively low cost, you can simply order a second, standard PSU with the Signature and power both boards that way. Do take heed that while that option is safe to run, Allo doesn’t recommend it for the best sound quality. If you can stretch your budget, you open the door to running your own choice of power supply to ensure cleaner power delivery to the SPDIF board. If you can’t afford a nice, clean linear power supply, Allo recommends utilizing their 4-pack 18650 battery power supply. You’ll need to supply your own batteries and charger for them, but estimated battery life in this configuration should be about 1-2 days.

The SPDIF portion of the Signature Player itself is split into two boards this time. The child board handles the actual I2S to SPDIF conversion circuitry and power delivery (with super capacitor upgrades), while the upper board houses the oscillators (also upgraded), buffers, flip-flops, and signal isolation. Given the additional board and taller stature, the Signature Player requires a new case, with only acrylic available as of this review. You can order the new boards separately, just drop the “Player” moniker, if you already own a Raspberry Pi B or B+.

With the additional board and power isolation, upgraded capacitors, and upgraded clocks, Allo claims they’ve further reduced jitter from the original DigiOne to less than 400fs. From a tweaker’s perspective, there’s more options on how you deliver power to the device.

These upgrades come at a price, unsurprisingly. A similarly equipped DigiOne Signature Player, including a second, standard power supply, is almost double the cost of the original DigiOne Player. This is assuming an acrylic case for both, since an aluminum case is not yet available for the Signature. That said, a fully loaded Signature Player will run you just shy of $350 USD. For a high-quality music transport, that’s still quite inexpensive. Let’s find out if the price differential over the original pays off.

Listening Setup

For listening tests, I remained mostly tied to my Sennheiser HD650 fed with the Eddie Current Super 7 or Massdrop x Eddie ZDT Jr. and Schiit Modi Multibit. Though a modest rig with the ZDT Jr. as the amp, the setup is quite capable of revealing subtle downstream changes.

When I needed to analyze pure bass quality, I’d gravitate towards the MrSpeakers Ether C or Aeon Open, the latter which has a similar, but overall cleaner, low-end tone as the HD650. For these, I’d pair them with the Schiit Magni 3. I also dusted off my ECP Black Diamond amp for some comparison tests, as I found it to be a bit more focused and ruthlessly revealing than my other amps.

One notable addition to my stable is the Schiit Eitr. I was longing for a good SPDIF source that I could pair with my PC for convenient listening and gaming, since the DigiOne Players both only act as music transports and/or streamers. I put the Eitr in the ring to make for a more interesting comparison.

Unlike my own DigiOne Player, I didn’t touch a single thing with the Signature Player. It came pre-installed with the DietPI OS and the Roon Bridge software. I simply hooked up the Ethernet, SPDIF, and then power cables. Roon found it automatically a few minutes later. I left it like that for my listening sessions.

For convenience, I’ll largely refer to the original DigiOne Player as just the “DigiOne” and the DigiOne Signature Player as the “Signature.”

Signature Sound Quality Improvements and Power Supply Experiments

I started my evaluation using Allo’s standard, 5V PSU across the board for both the DigiOne Player and Signature Player. Allo strongly recommends not using this PSU for the feeding the clean side of the Signature, but it is technically an option if you are very limited on funds. It’s perfectly safe, but they claim it hinders sound quality. Allo recommends buying some reputable 18650 batteries and using their own battery pack. Buy eight batteries, and a charger that will handle four batteries at once, if you want to rotate and never lose power. Nonetheless, I thought I’d use their standard, 5V PSU as a bare minimum baseline and wanted to report on it for those that might utilize it in this configuration.

I could tell immediately both DigiOne devices were in the same family, as they shared a very similar sound signature. This usually makes it easier to identify sonic improvements in comparison tests, since you don’t have to separate out different characteristics of the same overall quality. This was indeed the case with the Signature.

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