One slimline box, multiple functions – that’s PS Audio’s value-added Stellar Gain Cell DAC. But can this keenly priced multitasker live up to the expectations created by more senior members of the PS Audio product line-up, including the DirectStream and DS Junior DACs?

The rise of the do-it-all integrated amp, complete with built-in DAC, network connectivity and even Wi-Fi/Bluetooth/AirPlay capability, has been threatening the very existence of more conventional, separate pre-amp/power amp combo’s in the high-end audio arena.

After all, why deal with the clutter of two or three components if they can be replaced by one box with multiple capabilities? And besides, you end up with shorter signal paths, and no need for expensive interconnects.

Whether that single box can match the fidelity and performance of individual, dedicated components remains a moot point. When you cram so much circuitry into a single chassis, concerns about interference, signal integrity and the like become inevitable.

Despite its nomenclature, the PS Audio Stellar Gain Cell DAC is a one-box device fulfilling multiple roles. It combines the functions of a pre-amp, DAC and headphone amp in a slim, elegant enclosure.

Stellar is the name of PS Audio’s most accessible product range. In addition to the Gain Cell DAC, the line-up also includes the S300 stereo power amp, and the M700 monoblock. By usual high-end standards, the Stellar gear is attractively and accessibly priced, making value-for-money a further, vital attraction.

Available in either black or silver, the Stellar Gain Cell DAC looks the slimline, understated part. The aesthetics border on plain, but that’s a good thing. It looks attractive in a functional kind of way, while the all-metal construction adds a reassuring robustness to the package.

The fascia is adorned with little more than the obligatory blue-illuminating PS Audio power button, a rotary volume control, a clear OLED display and a 6,35 mm headphone socket. Look closer, and you’ll see input selector and set-up menu buttons, as well as an IR receiver sensor for the included remote handset.

The rear panel provides a better indication of the DAC’s extended functionality. In its role as a fully-fledged analogue pre-amp, with a balanced circuit configuration from input to output, the Stellar offers one XLR balanced and three single-ended RCA stereo inputs, as well as a choice of XLR or RCA stereo output sets.

The partnering on-board DAC hosts  a full suite of digital inputs, including Toslink optical, RCA coaxial, and asynchronous USB Type B. The HDMI-style socket is actually an I2S input, which allows native DSD transfer from compatible disc players, such as PS Audio’s own Digital Memory Player, without DoP (DSD over PCM) conversion.

The DAC is both PCM and DSD compliant, but conversion rates and bit depths depend on the digital input.

Thus, optical is limited to PCM only at up to 96 kHz/24-bit, and coaxial to PCM at up to
192 kHz/24-bit. USB offers PCM up to 384 kHz/24-bit, and DSD64 and DSD128 via DoP, while I2S will do PCM up to 384 kHz/24-bit, and DSD64 and DSD128 natively.

Two particular technologies are worth noting. The Stellar DAC’s pure-analogue pre-amp stage uses PS Audio’s Gain Cell technology for volume control. Simply put, Gain Cell varies volume by adjusting the actual pre-amplifier’s gain setting, rather than introducing separate attenuation in the signal path which could degrade signal quality and integrity.

Digital conversion is achieved via PS Audio’s proprietary Digital Lens, which consists of a simplified Field-Programmable Gate Array. Termed a Complex Programmable Logic Device (CPLD), it optimises the incoming digital signal through reclocking, wave shaping and jitter reduction.

The optimised digital data is then converted to analogue using a ESS Sabre 9010 32-bit Hyperstream DAC chip, followed by an analogue passive filter.

Talking of filters, the Stellar offers three selectable digital filter settings: slow roll-off, linear phase; fast roll-off, minimum phase; and fast roll-off, linear phase. These allow users to tailor the sound to suit personal preference, or the material being played back.

PS Audio considers the first filter setting the default, and it certainly sounds the most approachable, but to my ears, filter 2 sounded slightly more natural and open, while the third filter seemed to reveal more high-frequency detail, but also introduced a faint glare to the upper trebles.

Underlining the Stellar’s high sonic aspirations is the fully balanced Class A output stage and the presence of a large analogue transformer with seven regulators, high-speed switching diodes and 15 000 μFarad of storage capacitance.

The Stellar Gain Cell DAC arrived together with a Stellar S300 stereo power amp (review pending), and I ran the duo in tandem for much of the evaluation period. However, I also partnered the Stellar DAC with our Parasound Halo A21 power amp for the sake of comparison.

It’s important to note that the Stellar gear needs a lot of run-in time – the amp more so than the DAC – so budget at least 100 hours of playing time for the DAC, and double that for the amp.

Set-up was simple, with the pre/DAC’s balanced outputs used to link it to the power amp, and our Esoteric EX-03SE universal deck roped in as the transport. I didn’t have an I2S-compatible player on hand, so coaxial SPDIF was the digital input of choice.

Linking the USB input to a headless Mac Mini allowed music files to be sourced from my NAS-based digital music library, using Audirvana 3.2.5 as the playback platform. For a purely analogue signal path, an Avid Diva II SP/SME 309/Ortofon Cadenza Black aced as source via a Sutherland 20/20 phono stage.

The set-up menu allows access to an extensive list of functions and adjustments. Every input can be renamed, balance and max volume can be adjusted, and phase inverted. A home theatre pass-through function can be activated, and the display brightness and duration adjusted.

The Stellar can also be set to DAC-only mode, which bypasses the pre-amp circuitry completely, and allows the device to operate as a standalone DAC only.

As a pre-amp, the Stellar does a sterling job of presenting its musical wares with precision and honesty. This is not a pre-amp that will spin golden tones from sonic straw, but it won’t ruthlessly punish average recordings either.

Instead, it seeks to make the most of what it’s presented with, enthusiastically rewarding quality source signals, and benignly tolerating less than ideal material. It certainly doesn’t mess with the inherent substance or character of the music, neither adding a glow to cooler tones, nor sharpening softer hues.

What it does do is provide a wide-open view of the music, affording the listener ample insight, and revealing nuances and details that less observant pre-amps might have glossed over. It also does so with a sense of contextual validity, so that you never lose sight of the music’s emotive content, regardless of the recording’s technical highlights or shortfalls.

In essence, what the Stellar serves up always sounds more like music than hi-fi – and that in itself is a remarkable achievement.

I liked its ability to reveal the full sonic picture without resorting to drama or overkill – it generally made the music sound, well, just right. Staging, scale and dynamics were truthfully represented, reflecting the character and scope of the original recording.

The pre-amp’s tonal range was certainly broad enough to accommodate anything from chilly to chilli, but the Stellar steered clear of imposing an own, specific sonic signature on the music, preferring simply to reproduce what was already there – as any decent pre-amp should.

Those characteristics appeared to remain in place when I briefly used the Stellar as a headphone amp. It was quite happy to drive the rather challenging Sennheiser HD800s, but shone brighter with lower-impedance designs such as the HiFi Man 400S and the B&W P8.

If anything, the headphones highlighted the truthfulness of the Stellar, as well as its ability to create a seamless, generous and well-balanced sound picture. Add real agility and momentum to that picture, and headphone fans should be in their element.

The Stellar’s musically satisfying performance remained consistent, regardless of source, and irrespective of digital or analogue input signal, while also easily reflecting the differences in signal quality and character.

The Cowboy Junkies’  Trinity Revisited sounded particularly haunting, with the pre-amp capturing the full impact of Margo Timmins’ tender vocals soaring above the rich but thoughtful arrangements, all encapsulated by the venue’s reverberant acoustics.

The Stellar wasn’t in the least intimidated by the density of the recording, and especially the richness of the lower registers, maintaining both clarity and composure, while also affording the music air and sonic space.

Swapping to digital material, Chris Thile and Brad Mehldau’s eponymous collaboration made for riveting listening.

The opening track, ‘The Old Shade Tree’ might sound deceptively simple, with a sparse arrangement that augments Thile’s banjo and Mehldau’s piano with a smattering of vocals, but its intimacy and natural tone presented the Stellar with a not insignificant challenge.

The recording captures the close, intuitive interaction between the two artists with such intensity that the listening experience becomes a gripping and evocative one. To the DAC’s credit, it delivered its wares with a lucid assurance that drew me right into the heart of the music.

The banjo had just the right edge and attack to sound viscerally real, while the piano provided a smooth, melodic counterpoint. The result was an intriguing juxtaposition of sound and texture, with the almost strident vocals adding to the fascination.

The Stellar did a great job of representing tonal breadth, delivering the piano’s lower registers with power and authority, while preserving the agility and zing of the banjo. It also tracked the music’s considerable dynamic shifts with precision, further benefiting the authenticity of the listening experience.

How good is the DAC section? Well that depends on your personal benchmark. Sonically, it’s adept and wholesome, painting the music with confident strokes, and using its bountiful harvest of detail to create a full, panoramic music picture.

It’s generous in the staging department, too, but compared to the (much more expensive) DirectStream DAC, the sound picture isn’t as holographic, and the  imaging not quite as finely focussed.

The DirectStream delivers its wares with greater urge and foundation, too – but given how much affordable the Stellar is (and the fact that you get a full-fledged pre-amp as part of the deal), the value proposition is impressive to say the least.

The PS Audio Stellar Gain Cell DAC proves that high-end can be had for less than you think. Combining pre-amp and DAC (plus that headphone amp) makes practical sense, while ensuring exceptional versatility.

But it’s this pre/DAC’s engaging musicality, together with real bang for the buck, that sets it apart. Indeed, it may just be the keenest weapon in PS Audio’s already impressive product arsenal. Now, how about a dedicated, no-frills, fully balanced Stellar pre-amp?

Digital conversion: CPLD (Complex Programmable Logic Device),     ESS Sabre, 32-bit
Formats: PCM, DSD, input-dependent
Frequency response: 20 Hz – 20 kHz (+0, -0,25 dB)
Signal-to-noise ratio: >110 dB (1 kHz, max output)
Digital inputs: 1x I2S, 2x coaxial RCA, 1x Toslink optical, 1x asynchronous USB
Analogue inputs: 1x stereo XLR, 3x stereo RCA
Outputs: 1x stereo XLR, 1x stereo RCA, 1x 6,7 mm headphone socket
Dimensions (WxDxH): 432 x 305 x 76 mm
Weight: 6,12 kg
Price: R22 100
Analogue meets digital in this innovative pre-amp/DAC with headphone facilities, too. Sonically, the Stellar always exceeds expectations, with finesse and believability its stand-out traits.
PL Computers. 082 578 5708

Esoteric Audio EX-03SE universal player
PS Audio DirectStream DAC
Avid Diva II SP/SME 309/Ortofon Cadenza Black
Sutherland 20/20 phono stage
Naim Uniti2 one-box system
Parasound Halo A21 power amp
Vivid Audio V1.5 loudspeakers
PS Audio P5 power regenerator
TelluriumQ Black interlinks and speaker cables
Synology DS213+ NAS
Mac Mini/Intel Core i5, 2,5 GHz, 10 GB RAM, 500 Gb HDD

Chris Thile/Brad Mehldau – Chris Thile and Brad Mehldau (Nonesuch)
Javier Limon – Mujeres De Aqua (Universal)
Billy Gibbons – Perfectamundo (Concord)
Mozart – Requiem – Dunedin Consort (Linn Records 192/24 FLAC)
Boston – Boston (Sony/BMG DSD64)
Fry Street Quartet – Beethoven String Quartets (Own Label SACD)
Cowboy Junkies – Trinity Revisited (Diverse Records LP)