Outboard DACs

Sean Kim, the Marketing/Sales Executive Director at HiFi Rose, has stated that the brand wants to ‘liven up the hi-fi market and have it embrace new technology faster’. That’s quite an ambition, and, to be fair, the South Korean company has already proven itself to be a successful disruptor – a case in point being the buzz generated by its ‘steampunk’ RA180 amplifier [HFN Jul ’22], and its network streamers sporting massive, customisable touchscreens [HFN Jun ’21 and Mar ’22].

So, here’s the RD160, its first standalone DAC. Abandoning the ESS chipset used in its previous streamer/DAC models, it packs the new flagship Velvet Sound Verita solution from AKM [see PM’s Welcome, HFN May ’24]. Currently, this is the highest-level DAC that AKM offers, consisting of a two-chip bundle, with the AK4191 noise-shaper/upsampler/digital filter handing over to the AK4499EX for the actual D-to-A conversion. No fewer than two pairs are used in the RD160, one set per channel, in conjunction with HiFi Rose’s own ‘I²S alignment’ regime running on a Cortex-A7 ARM-processor.

But before anyone gets to talking about what’s happening underneath the RD160’s hood, it will be this DAC’s appearance that gets tongues wagging. Causing a stir is de rigueur for this brand, and the RD160 unveils yet another design aesthetic here. When not in use, the DAC’s ten small metal buttons on the left of its front panel flank a larger space that remains completely blank. But switch it on, and a display (actually two separate OLED panels) lights up, and because it’s mounted behind translucent – rather than transparent – plastic, its white text and graphics have an unusual feel to them, almost reminiscent of e-paper. Off to the right, a larger dial is surrounded by a dimmable white LED ring shouting for your attention.

This fascia gives the RD160 its unique appearance, but look past it and you’ll notice its other elements are ‘typical HiFi Rose’. The thick top plate with the milled logo is one familiar aesthetic device, as are the cooling fins on the side of the chassis. I have no complaints about the build quality either, as the aluminium case has a gorgeous finish and, with black or silver colourways available, some partial matching of this DAC is possible with other HiFi Rose components.

Charting the way

There’s more to this device than a fancy industrial design, though. In keeping with its desire to be a force for change [see boxout], the RD160 presents the D/A process in its own particular way. In default mode, you’ll see a flowchart appear on the screen, highlighting the selected input, filter, upsampling and output – the route the signal takes through the RD160. If you love diagrams, the arc pattern that indicates volume – when used in variable output mode – will tickle your fancy even more. This ‘schematic’ display is bizarre, original... and I really enjoyed using it.

Above: Three linear PSUs [bottom] feed the digital and analogue sections of both left and right channels. The former utilises an RK3128 Quad core Cortex-A7 CPU [centre right], the latter with AK4191EQ/AK4499EXEQ upsampler/ DAC chips and J-FET outputs [top left and right]

While legibility isn’t great from a distance of three metres or so, it’s definitely more fun than boring text or a small LED telling you which filter you’ve selected. Also, compared to the button- and LED-infested Musical Fidelity M6x DAC [HFN Jul ’22] I occasionally use for testing, I found the RD160’s display more informative when exploring everything the DAC offers. A pure (large) text display is available if you prefer, and once music playback gets underway, all is replaced by two waveforms. These appear sluggishly and lack sharp focus due to the slightly frosted display, but this lends them an oddly ‘analogue’ feel – again, fun!

Generally, the remotes that accompany HiFi Rose’s separates are minimalistic in the extreme. That’s not the case here as the RD160’s remote is packed with buttons, making this one of the company’s few products you can completely control while sitting on the sofa. I found this handset to be much more intuitive to use than the buttons on the unit itself.

Flower power

Setting the RD160 apart from a slew of entry-level AK4191/AK4499EX-based DACs from challengers including SMSL, Topping and Eversolo, HiFi Rose has added more to the mix to justify the price. Three custom linear toroidal power supplies lay the foundation, powering the digital stage and the left and right analogue output stages independently. A lot of effort has been put into keeping the core digital and analogue stages apart [see inside picture, p66], the designers describing this architecture as ‘Rose CIM’ (Completely Isolated Modules).

Above: Digital inputs span optical (192kHz/DSD64 DoP), two coaxial and AES/EBU (384kHz/DSD128 DoP), HDMI/I2S (768kHz/DSD512), USB-B and SFP (768kHz/DSD512). Two clock ins are included, plus balanced (XLR) and single-ended (RCA) analogue outs

The DAC and balanced analogue output stages, the latter employing low-noise J-FET op-amps, are separated onto two mono PCBs for the left and right channels. All the digital processing, including the various PCM/DSD formatting, digital filter and upsampling options, as well as its channelling to I²S, is accomplished on the central PCB. The OCXO clock is based here too (this is the large-ish metal can in the centre), though HiFi Rose does offer the facility for an external clock to be attached.

Flexible friend
The feature set and connections of the RD160 allow for plenty of choice when fitting it into a wider system, including pre-out levels ranging from 1V to 9V, which can be adjusted on the fly using the large dial on its front panel. This would be handy if you were to connect the RD160 directly into a power amplifier, but I opted to use it with an integrated amp: HiFi Rose’s EISA Award-winning RA280 [HFN Apr ’24]. In this set-up, the RD160 seemed to add little in terms of colouration and appeared quite transparent. It resolved lots of detail, especially through the analytically minded Focal Sopra No2 floorstanders [HFN Sep ’15] I used, but traces of harshness or artificiality were absent.

Playing the Akademie für Alte Musik Berlin’s Bach Brandenburg Concerto recordings [B0991J76PS; Harmonia Mundi; 192kHz/24-bit], via Roon and an Eversolo DMP-A8 [HFN May ’24], drafted into digital streamer duties over I²S, ‘II.Adagio’ from Concerto No.1 in F Major was presented in a pleasantly flowing manner. The oboe leading the way sounded very natural, segueing into finely portrayed baroque strings, and the scale of the recording was appropriately conveyed. With eyes closed, I was almost convinced I was listening to the live performance at the Jesus-Christus-Kirche in the German capital.

Open wide

That said, when ‘zooming’ in on individual instruments I missed being able to place them with confidence on the stage. Of course, this is never easy with orchestral pieces recorded in great halls, but when I have listened to this album in the past via the same loudspeakers and a T+A DAC200 [HFN May ’22], there was a heightened sense of accuracy. But I wouldn’t want to overstate this: the performance certainly didn’t come across as being smeared, rather a more spread-out image in general, and this didn’t make the listening experience unrewarding. HiFi Rose’s debut standalone DAC hit the spot on multiple fronts and delivered convincing immersion when ‘IV. Menuet – Trio I – Polonaise – Trio II’ came around.

And not every recording features a big, live sound. There was a beautifully spacious feel to the RD160’s portrayal of ‘Yok Haddi Yok Hesabı’, an 11-minute track from Turkish psychedelic rock band BaBa ZuLa [Istanbul Sokakaları; Glitterbeat GBCD163; 48kHz/24-bit], particularly in its handling of the varied scattered percussion, which includes the tinkle of falling coins. The HiFi Rose DAC was in its element with this layered, focused piece, maintaining the feeling of its hypnotic build-up while still neatly exposing the characteristic twangs of the stringed saz – a Turkish/Middle Eastern instrument the band amplifies to get a sound that sits somewhere in between folk and metal.

Switching to a Pro-Ject CD Box RS2 T CD transport [HFN Sep ’19], connected via AES/EBU, I spun Gustav Mahler’s Symphony No.1 and the unfinished Symphony No.10, found on Disc 1 of the Leonard Bernstein Conducts Mahler box set [Sony Classical; 19439708562]. The change of source didn’t yield a change in the RD160’s demeanour – the grand orchestral dynamics on ‘II. Kräftig Bewegt’ found the space to express themselves, at the same time as softer passages offered subtle, light detailing that invited me to ‘lean into’ the recording. Again, the impression was that of listening to a concert performance in its totality, which isn’t a downside when dealing with Mahler.

Striking a balance

The virtuoso playing of Anne-Sophie Mutter during John Williams’ Violin Concerto No.2 [Deutsche Grammophon 00289 480 2012 8; 96kHz/24-bit] was on the cusp of being not quite pronounced enough, yet this will depend a bit on personal taste – if you prefer individual instruments to be accentuated, above getting a more integrated view of an arrangement, the RD160 might not tickle your fancy. On the other hand, I did often enjoy the balance struck, which HiFi Rose’s Sean Kim states informed the selection of this DAC’s dual-chip AKM package.

Above: PThe RD160 has a ‘dedicated remote control’ offering access to input, mute, volume, sampling and filter modes, display appearance and menu navigation

An element of the appeal of this flagship unit is the convenient way in which you can play around with its digital filters and upsampling. Yes, most DACs offer similar capabilities, but the interesting thing about the RD160 is that you know exactly what you’re doing, thanks to its OLED display. You’ll be enticed to experiment, even if that’s not your nature.

Season to taste

During testing, I felt the greatest positive impact on performance was achieved by instigating the unit’s PCM upsampling to the maximum rate (768kHz or 705.6kHz, depending on source). As often with AKM chipsets, conversion to DSD brought with it a hint of a smoothing effect – a lesser sense of resolution but a more fluid sound – as evidenced when listening to Feist’s Multitudes album [Polydor 4873183; 88.2kHz/24-bit], but you do need to take into account the drop in level during comparison to PCM modes. Furthermore, as it’s easy to experiment with, I assume RD160 owners will go out and discover what they prefer. For some, playing around with these variables will be an end unto itself.

Hi-Fi News Verdict

With the promise inspired by the implementation of a pair of AKM’s flagship DAC solutions, the RD160 is clearly no run-of-the-mill product. In practice it delivers the goods, offering a smooth, detailed sound albeit favouring broad soundstaging over pin-sharp positioning. Otherwise, the unique design not only attracts visually, but also adds an element of fun and exploration in use. And there’s nothing wrong with that!

Sound Quality: 82%