Heed Abacus S streaming DAC
Hungarian hi-fi manufacturers are not two a penny, at least not among brands available in the UK. From what I have seen and heard from them over the years, Heed Audio like to do things a little differently. I purchased their Cannalot III, Class A headphone amplifier a couple of years ago, and it continues to impress, particularly with the addition of the QPSU III power supply last month.
Here, we are looking at the latest iteration of their Abacus DAC, which includes a streaming module; give your head a wobble if you thought the S was for sport. The Abacus DAC, like the company’s Elixir amplifier, has always been a half-width product. Such packaging can be a potential headache for engineers, but those who get it right can attract customers for whom space is at a premium. When I think about it, I cannot name many high-performance streaming DACs that take up this little space, and those that include a linear power supply make for a list that is shorter still.
No details are provided of the chip used, which I think is fair enough, as many listeners tend to assume that the performance of a given DAC will be tied to the sound of the chip used. In my experience, implementation is key, and factors such as post-conversion filtering and a quality of power supply tend to be far more critical. What we do know, however, is that the Abacus S can support PCM files up to 32/384kHz and DSD up to DSD256.
The Abacus is still available without the streaming module for £1,650. The Abacus S we are looking at here costs £2,100, so that’s an increase of £450 if you go for the streamer. For sure, you can buy a separate streamer for less than this, but, considering the extra space and cost of cables required to get the best out of such a device, not to mention that lower-cost streamers tend to lack DSD compatibility, I consider this to be excellent value.
Design and build
The Abacus S is a simple yet solid and well-put-together component. The facia is as simple as it gets. As you can see from the photos, it is limited to a numbered button for each input and a text display. Setup is accomplished with the aid of the remote. You can also select from various digital filters, including two which are specifically for DSD. I like the way the display scrolls sideways, which is pretty cool. The casing mirrors that of the Elixir amplifier. The pair would obviously make a good match, but the Abacus is a standalone product that should work well with pretty much any amplifier.
On the Abacus there are two inputs for SPDIF coax (RCA and BNC), two for optical and one for USB. The sixth button selects the streamer. The connections for this are via a USB-A input socket, which is an unusual way of doing things. If you want to use wi-fi, you plug in the supplied antenna to the USB socket. Making a wired connection requires the converter provided, which appears to be a generic device, consisting of an ethernet socket on the end of a USB cable. My son uses something similar to connect his Nintendo Switch to a wired network. It is the first time I have seen such an arrangement on a high-performance streaming DAC, but it worked well enough. Setting up the wi-fi caused a few minutes of head scratching, but for most, it will be a one-time job, and the connection was flawless, even with high-resolution files, such as DSD, streamed locally.
Outputs are RCA only and thankfully the sockets are proud enough of the casing to accept high-quality plugs, unlike my Chord Hugo2. The MCRU No. 71 cables, which we reviewed a few months ago, did a sterling job here. The Abacus has a three-pin mains IEC input, which allowed me to use a decent mains cable from Russ Andrews.
Turning numbers into music
I have mostly been using the Abacus S in my headphone-based system, which I have to say has proven to be remarkably addictive. This system is based around my Heed Cannalot III headphone amplifier, which has benefited hugely from the addition of Heed’s QPSU linear power supply. I had a Wiim Ultra feeding a Denafrips Iris/Ares 12th DDC/DAC combo on hand for comparative purposes, along with the Chord 2Go/Hugo2. I mostly used a pair of the recently launched Meze 105 Silva headphones, but resorted to my now tired-looking HiFi Man Sundara ‘phones once those were returned.
The Abacus S is a punchy-sounding device, but one that is remarkably composed and well-behaved throughout the frequency range. By comparison with the Denafrips, the presentation is less airy and spacious, but the Abacus S makes up for this with superior rhythmic drive and cohesion. The soundstage is particularly wide and has a good sense of depth and height, but perhaps is slightly restrained in the forward plane. This presentation benefited when listening to a rip of the recent Analogue Productions SACD of Genesis’ A Trick of the Tail, which was streamed from my Melco over the network.
As a side note, I was impressed that I was able to stream DSD files wirelessly despite the Abacus being some considerable distance from the router. This album has tended to sound somewhat bright and thin, and despite the improvements wrought by this latest SACD release, it still leans towards such a balance. The Abacus S made the best of this and produced a thoroughly captivating performance. The Abacus S had no trouble revealing the original recordings’ wide dynamic range, which this particularly good on this release.
I had forgotten how much I enjoyed the album Real Life by Joan As Police Woman, but was reminded when I heard a track from it on the radio a few weeks ago. The Abacus S presented this warm and full-bodied, but slightly ‘earthy’ recording well. The bass sounded particularly full and ripe, yet well under control here. The intro to tracks such as Save Me and Anyone sounded particularly punchy through the Abacus S yet never overpowering.
Hania Rani and Dobrawa Czocher’s Inner Symphonies demonstrated the Abacus S’s skills at handling more delicate and subtle music well. This DAC/streamer resolves high amounts of detail and reproduces the piano with a smooth yet natural tone. The strings were delicate yet well-defined. The presentation was slightly darker than through the Denafrips or Chord DACs, but there was no lack of detail or drama. By comparison, my Chord 2Go/Hugo2 impressed in the ways that Chord products are famed for, such as detail, soundstage placement and speed. However, the Abacus S gave a richer rendition of strings with a more natural decay of notes.
The Abacus S acquitted itself well in the main system, which at the time included the Vitus RI-101 MkII and Oephi Transcendence 2.5 speakers. Sharing the rack with a Moon 780D and the Vitus’s internal DAC meant it had big shoes to fill, but this Heed gave a refined performance with a good sense of musical flow. For sure, Abacus S lacked the zeal and immediacy of the far more costly DACs it replaced, but I enjoyed the music it produced, nonetheless. The Abacus S gave a particularly enjoyable rendition of Marillion’s Clutching at Straws Blu-ray Audio disc, which was ripped to the Melco and streamed over the wired network. Here it delivered a meaty performance with no lack of weight or drive.
Plugging in the TV via the optical input and an Oppo 103D Blu-ray player worked well. Again, that refined, civilised and lively presentation made the best of whatever I fed it. I also played around with the Abacus S’s digital filters. Generally, I preferred the ‘Soft’ option, which to me sounded more spacious, albeit at the expense of little definition, but it was still satisfying enough in this regard.
A streaming DAC you can count on
My time with the Abacus S has been enjoyable, and I often forgot that I was supposed to be reviewing it, it provided so much engaging music. It is a comparatively discreet device that, once set up, provides a rock-solid wi-fi connection. I like the simple looks, solid build quality and the no-nonsense way it goes about making music. Sure, it has a slightly darker presentation than some of the competition, but there is no lack of life and drive to the music. It is one of those products that sounds great with anything you play through it, including those recordings that can sound unpleasantly harsh through rival products. You can buy DACs that tell you give you a more airy sound, but they will likely fail to match the Abacus in other areas of reproduction, or cost far more money.
Whether you pair it with other Heed products, such as the aesthetically matching Elixir, or something outside this Hungarian brand’s stable, the Abacus S is a great way of adding streaming to your system, as well as being a fun, yet refined digital hub for existing sources. I could certainly live with it, and I think many buyers will enjoy doing just that.