But if I’m honest, I have to admit that the digital side of my system has become more accurate-sounding and, somehow, more clinical-sounding as well. Was it the Mac operating system upgrades, from Sierra, Mojave, High Sierra, and Catalina? Had I not correctly configured the Mac? Maybe I hadn’t used the right music-management program. I’m not sure what the correct answer was, but I do know that the sound had become less vivid and enticing than I was used to and I wasn’t listening to digital music with a deep level of involvement.

So it was with great interest that I read an e-mail from Gary Dews of BorderPatrol urging me to try the Innuos ZENmini Mk 3 and its companion LPSU power supply. I had been impressed by the BorderPatrol, Volti Audio, and Triode Wire Lab system at AXPONA, and they were using a Mac Mini as the source, so if Gary had moved on to Innuos, it was time to see what the company's least expensive pairing might bring to my system.

The ZENmini Mk 3 is a standalone CD ripper and music server. Its main processing chip is an Intel Quad Core N4200, the successor to the i5 chip used in my older Mac. Internal memory is 4GB, and my review sample came with a 4TB hard drive for storing music files. A TEAC slot-loading drive is included for ripping your own CDs. The review samples were black, but silver is an option and looks very attractive on the Innuos website.

Music tracks can be sourced from the ZENmini’s internal hard drive, a NAS drive on your network, or streamed from Internet radio stations, Qobuz, Spotify or Tidal. Ripped music is stored as either FLAC or WAV. but playback formats include WAV, AIFF, FLAC, ALAC, AAC, MP3, and even MQA for those DACs that support it. Bit depth is 16, 24, and 32 bits, and the ZENmini Mk 3 can handle sampling rates from 44.1kHz through 384kHz. DSD files (up to DSD128) can be handled as either DoP or as native files if your DAC is capable. Finally, the ZENmini Mk 3 can also be configured as a Roon Core or Roon Bridge if you need that functionality. That is a lot of flexibility for Innuos’s entry-level server.

The ZENmini is housed in an attractive half-sized case that's 2 3/4”H, 8 3/8”W and 9 1/2”D, with only a CD slot and small power button intruding on the sculpted, angular front panel. The rear panel has a small jack to plug in the provided switching power supply, a set of RCA jacks, TosLink and S/PDIF digital outputs, and four USB slots for connecting to your audio system or connecting USB hard drives to import your music to the internal hard drive. It also has a pair of Ethernet ports allowing the ZENmini to connect to your LAN or as a server for multiple home systems. One word about the USB ports: they do not allow playing music directly from memory sticks or portable hard drives; rather, they are used to import files to the internal storage. Because the ZENmini Mk 3 can be configured with storage capacities from 1TB to 8TB, you'll want to choose your storage needs carefully if you are not planning on setting up a NAS drive in your system.

The optional LPSU comes in a matching-sized chassis. The rear panel has a IEC input, power switch, and a threaded plug that is used to attach a short umbilical linking the LPSU with the ZENmini. The cable’s length allows for either side-by-side or stacked placement in your rack. I came to view this optional power supply as a necessary addition in order to hear the ZENmini at its peak performance.

To keep internal noise to a minimum, the ZENmini Mk 3 does not include WiFi or Bluetooth, so a hard-wired Ethernet solution had to be found for my listening room, which is about fifty feet from my modem and router. Running wires down the hallway during the review period simply wasn’t an option. Nuno Vitorino, Innuos’s head of technology, suggested that a WiFi extender with an Ethernet port would work well, but also that a pair of Netgear Powerlines had worked well for his customers. This type of Ethernet extender uses your house A/C wiring to transmit the Ethernet feed from a modem to any outlet in the house. (After the review period, one of my Powerlines developed noise that caused my tube amps fits, causing intermittent pops and sizzles. I replaced the Powerlines with a Linksys WiFi extender that solved the problem.) One last necessary task is to download an app to allow remote control of the ZENmini Mk 3. Apple users will need to use iPeng9 for iPhones or iPads, and Android users can use Orangesqueeze for their phones or Squeeze Control for their Windows desktops.

ith the Ethernet connection working and my iPad app installed, it was time to play music. The initial setup process may sound a bit difficult at first, but it was fairly intuitive and easy to perform. After powering up the ZENmini Mk 3 for the first time, you open a browser on your computer or mobile device and enter “my.innuos” in the URL line. A window opens identifying the Innuos product. This window is the command center for setting up the ZENmini Mk 3 and includes options for disc-ripping speeds and storage formats, modifying stored files metadata, logging into Tidal, Qobuz, or Spotify, and adjusting the necessary settings for Roon. Once you have decided how you want the ZENmini Mk 3 to operate, you will only need to access this window to change settings or manage the metadata of your ripped files.

To assess the benefits of the LPSU, I began my listening with the stock switching power supply and used the RCA outputs to let the ZENmini Mk 3 burn-in. My initial impressions were positive, with a wider soundstage than I was coaxing out of my computer-based playback and improved bass attack and speed. In many ways, the sound of the ZENmini Mk 3 with the switching power supply reminded me of a good CD player but with lower resolution and less tonal color than I get with my computer and DAC.

After the burn-in process was complete, I decided it was time to add the LPSU and switch to USB to feed my BorderPatrol DAC SE. “Malena” from Sera Una Noche [MA Recordings MO 52A] now had real depth and a spacious soundstage that I hadn’t been able to coax out of my new Magnepan LRS speakers. With the ZENmini Mk 3 and LPSU, I was finally hearing much of what Wendell Diller of Magnepan had achieved during the LRS debut at AXPONA 2019. Besides a wider and taller soundstage on this track, Santiago Vasquez’s hand drums had faster leading-edge attacks. This was a welcome outcome because I had always thought percussive dynamics were a slight weakness in my computer playback system. Before listening through the RCA outputs with the stock power supply, these hand drums were generic thumps, but the combination of USB wiring and the LPSU power supply revealed subtle strokes and how Vasquez struck different places on the drum heads to achieve different effects.

Performers in various recordings were portrayed with greater resolution, their images more solid with less haze around the edges. Some digital products present images outlined in a subtle grit or edge, giving the illusion of definition. With the ZENmini, vocals were darker in tone and set further back in the soundstage, making José Cura’s recording of “Cancion del arbol del olivido” on Anhelo [Erato 3984-23138-2] more natural and realistic -- as if I were transported to the recording’s original venue, with great depth of image and improved vocal purity on full display. I’ve listened to this track numerous times, so the added clarity and definition were a bit surprising to me. I had previously thought my computer-based system was pretty good at this aspect of reproduction.

In the same vein, José Carreras’s voice was placed further back in the cavernous acoustic of Santurario de la Bien Aparecida on his recording of “Missa Criolla” [Philips 420 955-2] without losing any clarity. If I had to name the Innuos pair’s one singular strength, it would be the ability to present vocal and instrumental lines with high resolution and enhanced engagement during dense musical passages. Additionally, the LPSU gave dynamic swings a sense of freedom, as if a limiter had been lifted from recordings.

After comparing the sound with the LPSU in and out of the system, I realized I have heard similar restrictions in some of my audiophile friends’ computer-based systems. After several weeks enjoying the ZENmini Mk 3 and LPSU, I packed them into my car for a road trip to a system that could play with greater dynamics and bass slam than the little LRSes were capable of. I’m fortunate to have fellow The Audio Beat reviewer Vance Hiner just one hour from me. His system, featuring Wilson Sasha 2 speakers driven by a Conrad-Johnson Premier 350 amp and fronted by a CAT preamp, can certainly plumb the depths of recordings. We connected the ZENmini Mk 3 to his Audio Research DAC using a Shunyata Sigma S/PDIF cable.

Why begin listening via S/PDIF instead of USB? Previous sessions with USB connection to a laptop had not been successful and Vance felt that the S/PDIF connection to the Audio Research DAC was superior to USB. I had been present for some of those sessions and agreed that we should start with something we knew would work well.

To familiarize another listening buddy, Jason, and myself with his normal digital streamer’s sound, Vance informally switched back and forth between his first-generation Auralic Aries and the ZENmini Mk3. While none of us intended this listening session to become a shootout, one aspect became clear. The ZENmini was the Auralic’s equal in most respects, but it could not, in any configuration of power supply or cabling, quite equal the bass slam and power of the Auralic. Certainly it could match the speed of bass attack, but the Auralic had more force and body to bass drums and low bass notes. With our listening group acclimated to the overall sound and the system well warmed up, it was time to see if my observations at home would transfer to another system.

I kept the demonstration simple, limiting it to one track from Holly Cole’s Temptation [Metro Blue CDP 7243 8 31653 2 2]. “Tango 'til They’re Sore” begins with deep bass tones, then Cole inhales followed by a “ooh” vocalization. Around 1:30 into the track, piano arpeggios are played multiple times over the vocal line. With the standard power supply and S/PDIF connection, Cole’s breath was slightly obscured by the bass notes, then re-emerged as the bass notes died away. The piano arpeggios sounded clumsy, as if the pianist wasn’t sure if he or she wanted to play a chord or an arpeggio. In general, the sound was acceptable but lacked emotion and failed to draw any of us into the performance.

After we switched from the stock power supply to the LPSU, bass notes tightened up considerably and Cole’s vocals became one complete sound. Her breath intake flowed smoothly into the “ooh” and started to sound like a real vocalist in the room. The piano sounds were now clearly shown to be arpeggios, with the first entrance being a little less cleanly played. We had been using Shunyata’s S/PDIF cable, so I asked if we could change to the Sigma USB. As Vance switched cabling, he reminded me again that he hadn’t had much success with USB, preferring AES/EBU or S/PDIF connections. It wasn’t lost on me that the Sigma USB cable costs more than the ZENmini Mk 3 and LPSU combined, but because the S/PDIF cable was also part of Shunyata’s top Sigma line, it seemed fair to give it a try.

I was very happy we made this switch. Now Cole’s voice was completely separated from the bass tones, and I could hear her voice “spinning out the air,” as I’ve heard vocal conductors describe it. Her image was slightly more recessed into the soundstage, and enhanced dynamic shadings were back, making the performance more believable. The piano arpeggios were cleanly delineated, and each note was more easily recognizable. Interestingly, the USB connection revealed that the sustain of the piano arpeggios created a shallow arc from speaker top to speaker top. That artifact hadn’t been present in the recording through any of the cabling or gear changes. With a big smile on my face, I knew we had found the best combination.

The sound was so enjoyable that we took turns playing DJ on Tidal and Qobuz, spinning our favorites. After an impromptu sing-along on Dr. Hook’s “Sylvia’s Mother” and “On the Cover of the Rolling Stone,” we moved on to the swamp-country boogie of Jeb Loy Nichols’ Country Hustle on Qobuz. On the Bahamas' Earthtones, also on Qobuz, the different tonality of the microphones for the lead vocalist and backup singers on “Alone” had never been more obvious, but I did notice that the backup singers were not quite as well separated as I’d heard them on vinyl. We even managed to enjoy Jim Reeves from an MP3 file. While I’ve had many enjoyable listening sessions with Vance’s system, this was by far the most fun I’d had listening to digital files at his house.

USB ended up as my favorite connection for the ZENmini Mk 3, so I need to add a word about cable choice. In my system, the USB output was quite sensitive to the cable used, and you may not hear the ZENmini Mk 3 at its best without some experimentation. The inexpensive but good Oyaide Neo d+ Class A USB has always been an easy recommendation, but with the ZENmini MK 3 and the BorderPatrol DAC SE, the treble became spitty and harsh with an unmistakable glare. The wonderfully good and super-expensive Shunyata Sigma USB delivered a deep and rich soundstage with excellent image placement. But its cheaper stablemate, the Venom USB, was slightly cleaner in the lower treble in my system, so I settled on it for long-term listening. It’s nice to know that the ZENmini Mk 3 could resolve these differences while not costing more than the cable's itself.

What are the disadvantages of the ZENmini Mk 3 and LPSU? The absolute need for Ethernet might be a small impediment, but Ethernet over either A/C devices or WiFi extenders worked great. The lack of Bluetooth or AirPlay could absolutely be a non-starter for some audiophiles, as would the inability to use portable hard drives as playback devices. I have heard more expensive units do a better job at fleshing out images in the back of the soundstage and, while the ZENmini's bass was nimble, it certainly lacked some slam and body behind the initial bass hit. Finally, if you own the ZENmini Mk 3 but use it without the LPSU, you are missing out on much of its magic and you’ll need to find the funds to complete the pair.

udio satisfaction can transition to audio complacency, which is never a good thing. Sometimes a new piece of gear will arrive to wake you up and give you a good swift kick. I had been content using an inexpensive computer for digital audio, certain in the knowledge that I could download any number of helper programs designed to improve the sound. Some programs bypassed Core Audio, others used special algorithms for improved sound, and still others allowed me to stream audio from Tidal or Qobuz. Each one brought better sound that somehow managed to keep me at arm’s length, to keep me from enjoying my digital music library.

With the addition of the Innuos ZENmini Mk 3 and LPSU, my complacency is gone, and I’m excited about my digital sound again. Their sound is warm and spacious with increased definition. By the time you read this review, I will have retired my old computer system and joined the ranks of happy Innuos owners. The ZENmini Mk 3 and its optional LPSU are a highly engaging pair of music-makers.