California-based Aesthetix has carved out an enviable niche producing very-high-performance products that, while not budget-priced, nonetheless offer extraordinary value. The company’s Calypso linestage, Rhea phonostage, Janus full-function preamplifier, and Atlas power amplifiers pack a lot of innovation, superb build-and parts-quality, and great sound into the upper-end, though not stratospheric, price category. (Aesthetix does, however, offer two mega-priced, ultra-tweaky products, the Io Eclipse phonostage and Callisto Eclipse linestage.)

Aesthetix has now complemented its more affordable line with the addition of the Romulus CD player/DAC. In keeping with the company’s signature technology, the Romulus features a tubed output stage. In addition to spinning CDs, the Romulus can accept a digital input in a variety of formats including USB. For those of you who have dispensed with CD, Aesthetix’s Pandora DAC is identical to the Romulus sans disc transport.

Technical Description
The $7000 Romulus has a fixed output level for use with preamplifiers. For an additional $1000 the Romulus includes a variable output for driving a power amplifier directly. The large front-panel display doubles as a volume control—push the right side to increase the volume and the left side to decrease. The circuit that realizes this variable output exemplifies Aesthetix’s innovation and commitment to sound quality. Rather than simply attenuate the signal in the digital domain and accept the resolution loss (every 6dB of digital-domain attenuation is equivalent to throwing away one bit of resolution), Aesthetix has combined analog and digital attenuation in a novel circuit. Decreasing the output level attenuates the signal in the digital domain just as in other DACs with a variable output. But when you reach 6dB of attenuation, a relay engages resistors that replace the 6dB of digital-domain attenuation with 6dB of analog-domain attenuation, resetting the digital-domain level to full scale. Voîlà!—variable output without any meaningful loss of resolution at any output level. In practice, this transition from digital-domain to analog-domain attenuation is transparent to the user, save for a relay click when every 6dB threshold is crossed. The volume steps are 1dB, which is a little coarser than what is found in most DACs, but I didn’t find it a problem. The variable output circuit is, incidentally, housed on a board that plugs in vertically to the horizontal motherboard.

The Romulus incorporates other interesting design techniques, including a SPDIF receiver and clocking circuit based on a fixed-crystal clock. Most SPDIF input receivers are built around a VCXO (voltage-controlled crystal oscillator), whose output frequency can be adjusted by an external voltage. By “pulling” the clock frequency slightly the DAC can lock to the incoming clock rate. A VCXO, however, isn’t quite as precise as a fixed-frequency crystal. Aesthetix solves this problem by using a fixed-frequency crystal and running the data through a memory buffer. Presumably the buffer is large enough to “fill up” sufficiently before outputting the data so that the buffer doesn’t run empty if the Romulus clock is faster than the incoming clock, or conversely so that the buffer doesn’t overflow if the Romulus clock is slower than the incoming clock. In practice, there’s no time lag between pressing “Play” and hearing music, suggesting that a larger buffer isn’t required.

The SPDIF inputs are galvanically isolated so that ground noise on source components doesn’t get into the Romulus. They can accept datastreams up to 192kHz/24-bit. The input circuits are housed on removable boards to allow future upgrades as new interfaces become available. The same crystals used in the SPDIF input receiver are also used in the USB input circuit. It goes without saying that the USB input is asynchronous, meaning that the Romulus serves as the master clock to which the USB source must lock. Other digital inputs include TosLink optical and AES/EBU.

The 8x oversampling digital filter software is written in-house by Aesthetix, and runs on a Motorola DSP56362. Creating a custom filter is considerably more expensive and time-consuming than buying an off-the-shelf filter chip (or using the filter built into most DACs these days), but allows the designer to employ more sophisticated filtering techniques, and to tailor the filter’s sound to the context of the entire product. The digital filter has a large effect on the product’s sound, which is why many DACs that use the same filter/DAC chip sound quite similar.

The filter’s differential outputs (+ and –, or the datastream and the datastream inverted) are converted to analog by a Burr-Brown PCM 1792 chip operated differentially. With four DACs in one package, the PCM 1792 can process the L+, L-, R+, and R- separately. The downstream signal path—current-to-voltage converter, gain stage, and output buffer—is also balanced all the way to the XLR jacks. This is the right way to create a balanced analog output signal. The less expensive, but more common, alternative is to convert the digital signal to analog with one DAC and one analog signal path per channel, and then create a “balanced” signal with a phase-splitter just before the XLR jacks. Not only does this latter technique add an additional active stage to the balanced signal path, but it also doesn’t realize the benefit of differential DACs. One of these benefits is that any noise or distortion common to both DACs will cancel when the balanced signal is eventually summed, not to mention the increase in signal-to-noise ratio.

The output stage comprises a 12AX7 gain stage followed by a 6DJ8 output buffer. The circuit has zero global feedback. Tube-rollers can supply their favorite 12AX7s and 6DJ8s, but I evaluated the Romulus with the stock tubes.

The power supply is large and elaborate, with multiple regulated stages for powering different subsections. Even the analog, digital, and clocking sections of the PCM1792 DAC are fed from independently regulated supplies, each with cascaded discrete regulation stages. “Discrete” regulation means that the voltage regulators that maintain a constant DC supply voltage to the circuit are built from separate transistors (along with the peripheral parts that make them work). Discrete regulation is contrasted with IC regulation in which the regulator is simply an inexpensive three-pin integrated circuit. “Cascaded” means that the output of a voltage regulator feeds the input of another regulator, further purifying the DC that powers the audio circuit. Cascaded discrete regulation is expensive and consumes circuit-board real estate, which is why it’s usually only found in mega-priced products.

The input section, along with the Motorola DSP chip on which the filter runs, is powered by a separate power transformer and multiple independently regulated power-supply stages. The front-panel display and control section are also powered from a dedicated transformer. The 12AX7 in the gain stage, as well as the 6DJ8 output buffer, is fed from multiple supplies, including regulated heater supplies.

It’s impossible to overstate the power supply’s sophistication, particularly considering the Romulus’ $7000 price; such implementations are usually reserved for cost-no-object products. I suspect that this approach to the power supply, if not to the circuits themselves, was derived from the development work on Aesthetix’s flagship Io and Callisto. Having designed the best possible products without regard to price, designer Jim White knows exactly what effect power-supply topologies and parts-quality has on the sound, and is able to make the most intelligent trade-offs. Incidentally, White spent many years at Theta Digital before founding Aesthetix.

I should mention that the Romulus is available in a “Signature” edition that features the identical circuit, but with upgraded passive components and isolation feet. The upgraded components include the same expensive capacitors found in the Io and Callisto. When I compared Aesthetix’s Rhea phonostage to the Rhea Signature (whose only difference was passive parts-quality) a few years ago I heard a substantial improvement in the Signature version. The Signature edition costs $10,000 with fixed-level outputs, and $11,000 with variable-level outputs.

Listening
From the first CD, the Romulus impressed with its big, open, and expansive sound. It’s interesting how source components can allow a pair of loudspeakers to disappear into the soundstage— or not. Playing a CD that has captured a tremendous sense of space such as Dick Hyman’s Swing is Here on Reference Recordings made it immediately apparent that the Romulus didn’t suffer from the common CD ailments of congealing images and sounding bright without top-octave air. In fact, the Romulus was among the most open and airy digital products I’ve heard—at any price. The soundstage had wonderful dimensionality and depth, coupled with a sense of being “illuminated from within,” a wonderfully evocative phrase coined by Jonathan Valin to describe the classic Audio Research sound. Instruments toward the rear of the soundstage were presented with their tonal colors and spatial qualities fully realized, rather than blending indistinctly into the foreground.

Although the Romulus had tremendous bloom and air, it would be a mistake to interpret this as an artifact of a tubed output stage. On the contrary, image focus was tight and well defined, and the overall perspective was just a bit on the immediate and incisive side—not characteristics of a “tubey” sound. Nothing in the presentation suggested that I was listening to tubes, except the lack of a metallic, brittle character in the treble. The contrast between the up-front midrange presentation and the ability to see way back into the hall produced a soundstage of remarkable depth. The musical benefit was an ability to easily follow individual instrumental lines, no matter how complex the music or how subtle those lines—one of analog’s great strengths, incidentally.

The bass was remarkably rich, full, and weighty, yet still maintained a sense of speed and precision. The Romulus’ big bottom end served as the anchor for the rest of the presentation, beautifully conveying everything from the dense textures of orchestral doublebasses to the purring of a Fender Precision. Again, the Romulus didn’t sound like a tubed unit in its bottom-end impact, dynamic agility, and articulation. The midbass had a meaty quality that did wonders for an orchestra’s power range and some bass-guitar playing. On the title track from Donald Fagan’s Morph the Cat in 96kHz/24-bit the Romulus had tremendous low-end grip and power that conveyed the track’s visceral physicality. The Romulus is the antithesis of thin, threadbare, lean, or bleached.

The more I listened to the Romulus the more I enjoyed it musically, and the more I admired its sonic achievement. That statement may sound like a tautology, but some products can sound stunning sonically but fail to connect musically. The classic example is the super-high-resolution, dead-quiet, lightning-fast component that lays bare every last detail in a recording yet fails to engage the heart. It’s like a musician who shows off his astounding technical chops but has nothing to say. In digital products, this often results from a kind of mechanical quality that doesn’t really convince your brain that you’re hearing musical instruments rather than a collection of sounds. Such a product may hit many of the audiophile buttons, but there’s something not quite right—the presentation is built on an artificial foundation. The Romulus’ great appeal is that it avoids this pitfall completely. It sounds extremely “organic” and natural, without a hint of synthetic patina, particularly in the treble.

I’m glad that the review sample had the variable-output option installed, because driving a power amplifier directly revealed just how great this player is. The dynamic expression widened, the bass was fuller and went deeper, and transparency increased. It was comforting to know that no matter what the playback level (i.e., the amount of attenuation in the Romulus) I wasn’t losing resolution.

Fronting a world-class reference system of Constellation Centaur monoblocks driving Magico Q7 loudspeakers via MIT’s Oracle MA-X interconnect and MA-X SHD loudspeaker cables, the Romulus acquitted itself nicely under this ultra-high-resolution “microscope.” In fact, this system’s resolving power only emphasized what a terrific-sounding player the Romulus is; a lesser player’s flaws would have been that much more evident. Moreover, I compared the Romulus directly to what is unquestionably the state of the art in digital playback, the dCS Vivaldi. Of course, the Romulus was not the Vivaldi’s equal, but let’s just say that my opinion of the Romulus went up another few notches after this comparison when I reflected on the fact that the Vivaldi DAC and transport cost nearly ten times more than the Romulus.

Driving the Romulus through its USB port with a MacBook Pro running iTunes and Pure Music revealed the USB implementation to be excellent, although I preferred the sound of CDs played in the Romulus’ transport compared to rips of those CDs. The bass was fuller and better controlled, the midrange and treble smoother, and the soundstage more expansive. Remember, however, that the USB cable and the computer setup are significant variables when using a computer source.

Conclusion
The Romulus is another home run for Aesthetix, combining innovative circuit design, premium-quality parts and construction, and first-rate sound. This player was never anything less than musically communicative and immensely enjoyable, even in the context of a cost-no-object system. The Romulus is a flat-out bargain at its price, and invites comparison with much more expensive players. In fact, I’d call the Romulus a giant-killer, offering one of the highest price-to-performance ratios in digital playback today.

Digital sources built over the last few years have offered far more sophisticated sound than earlier ones. The same goes for D/A converters which is almost implied but also CD/Bluray decks. At the time of publication I reviewed the multi-format Marantz UD7007 and Cambridge Audio Azur 752BD for Audio magazine. I was surprised by how mature both sounded regardless of what type disc I spun or what sort of files I streamed. There are many reasons why such progress was possible. One was finding ways to deal with jitter’s time distortion. The other was that manufacturers finally realized that music is not just a group of sounds that must be delivered in the most precise fashion. They finally realized how complex music signal really is, how many subtle connections between timbre, pace, resolution, selectivity, focus, micro and macro dynamics must be acknowledged to obtain truly good sound.

The interesting thing about the former factor (which is obviously just my opinion) came strictly from engineering work. Jitter was measured, recognized and addressed. Truth be told, jitter measurements only took off once audiophiles complained that their CD players sounded less perfect than expected. The latter arrived from listening sessions that helped us understand correlations between various elements of music that must be reproduced to make playback natural. Taking into account both hard data from measurement-driven engineering and soft data from subjective listening allowed manufacturers to arrive at the point today where really good-sounding digital has become possible. One has to be impressed most by the improvements in the low-price level which goes for D/A converters like Cambridge Audio’s DACMagic 100, Arcam’s rDAC and rLINK or the Cambridge Audio Topaz 5 CD player. Each of them costs less than any one part of my system. It’s a real pleasure to find such gems amongst inexpensive machines and I’m pretty sure it was no easy task to make them sound as good as they do. Equally significant changes are happening in the high-end. The character of changes is similar to those already described but their consequences are much more complex.

Yet what connects the entry-level rLINK and today’s high-end Romulus still are the choices designers must make during the R&D process. There simply is no ultimate natural, neutral or absolute sound per se. What you may achieve is a bit less or more than this natural/neutral sound. And it gets more complicated. Two decks one might describe as similar in neutrality and/or naturalness will in general still sound very different, possibly day and night so. Think Romulus and M2Tech Vaughan DAC. This American deck might be defined as warm, rich, liquid and pleasant. These features reminded me of other very good players like the Mark Levinson N°.512 or EMM Labs XDS1 SE. These three have a similar sonic signature one might define as ‘analogue’ which in fact is rather a natural sound albeit not necessarily one that’s perfectly neutral. You might be surprised by this contradiction between natural and neutral. You might have assumed that neutral must equal natural as similar to what we hear in real life. But audio sets its own rules. One of them is that live music differs from what can be caught by tape or hard drive. That’s why neutral doesn’t have to mean natural. It’s more a description of choices the designer made and of listener preferences. And the Romulus—or better, its creators—focused most of all on music’s inherent beauty. That’s what you get when you decide to drive a power amplifier directly with the Aesthetix. Indeed in my system I preferred the sound of Romulus driving my Soulution direct over using the ultra-minimalist but expensive Ayon Audio Polaris III preamplifier. Ditto for Dan D’Agostino’s Momentum Stereo. With or without preamplifier? This question has been around forever but the answer remains the same. It depends. I’m not trying to avoid a clear answer. It truly does depend on two main factors in any particular system. What is the quality of the preamp stage integrated into a source; and is it capable of driving a particular power amplifier across a given length/type of cable? Usually designers of power amplifiers anticipate a separate preamplifier with proper gain, signal buffering and volume control. When one opts to forgo a preamp and connects a CD player’s variable output to a power amplifier, one should base this decision purely on whether one likes the sound. Whilst intuition might tell us that ‘less is more’ where skipping one, two or more gain stages ought to result in better sound, in fact we usually get quite the opposite. It mostly only works when a system was conceptualized accordingly from the onset, say Ancient Audio CD player/preamps and their matching power amps. Back to the Romulus, maybe 10 or 15 years ago a similar sound came from Wadia players. It was warm and three-dimensional with slightly softened attacks and a lush midrange. It made CDs sound really pleasant despite the problems the breed had at the time. That’s why Wadia then was such a popular brand. Its popularity was well earned. But perception of sound changes with time. Today Wadia’s sound would be perceived as significantly coloured. It still would be very pleasing but also be considered slightly dull, with resolution and selectivity that no longer compete with today’s standards. The Romulus somewhat reminded me of the Wadia 851 albeit without the latter’s issues. It delivered a warm though not warmed up sound. There’s a difference. Warmed up means coloured whilst warm means rich and not cold. The ‘warm’ expression doesn’t carry as much weight as ‘warmed up’. Aesthetix delivers a huge liberated sound which reminded me also of the Ayon Audio CD-5s Special. Yet it seemed that Romulus offered superior focus. Its bass might not have been as extended or thunderous but I don’t think anybody would complain. Instruments were projected quite close to the listener and very palpable. I think that was a function of a slightly emphasized lower midrange but not as some obvious coloration. It felt like a premeditated choice because it made the sound of the Romulus by creating its volume, size and dynamics. One feature everybody liked so much about the old Wadia machines and now with the Mark Levinson No.512 and EMM Labs XDS1 Signature Edition is how three-dimensional they sound. The Romulus now joins this club by delivering not merely large but also palpable physical objects across the audible range. Even so the picture stays very clear and sharp. This is a high-end player in every aspect including resolution. To verify I listened to some commercial CDs and compared them to their copies of master tapes I had on CD-R. That’s how some labels prepare their special formats like UDH (First Impression Music and T-TOC). The differences between master tape and regular stamped CD are quite significant and I always favor the CD-R copy. I think that’s why formats like XRCD are so successful. Part of the recipe involves simplifying the process between recording studio and final product. But even so several stages remain and each of them might introduce distortion. Regardless, the differences were clear and the Romulus presented them without hesitation. It portrayed much better dynamics, focus and a more interesting overall presentation for CD-R. It did it in its own way though. It showed clear differences between the sizes of various instruments and the distances between them and the listener. This confirmed my early impressions. Changes in dynamics were clear too though not as significant. A stock CD had flatter dynamics, CD-R more explosive ones. These were aspects the Romulus slightly emphasized. The performance of this machine could seem slightly limited because its selectivity was not as good as some high-end competitors. I recently had a discussion with Andrzej Kisiel, chief editor for Audio magazine, during which he asked me how I would define the difference between resolution and selectivity. He was right to point out something that I maybe subconsciously knew already. Too much or too little selectivity are always a problem. On the other hand resolution can’t ever be too good. It’s never good enough. If we understand selectivity like this, when talking about Romulus we should say that its selectivity isn’t quite enough. This is not a perfectly clean clear sound where everything becomes perfectly visible. One could even judge this sound as being less open than what one remembers from other machines with similar sonics. And in some ways one would be right. Strong crisp cymbals on Coltrane, Niemen’s Katharsis, on electronica like Diorama’s new Even Devil Doesn’t Care all were a bit too quiet and nice. If I remember correctly I used exactly the same words when I summarized my review of Devialet’s D-Premier AIR. Both show the music in a slightly more beautiful way than is true. They don’t allow for any harshness, brightness or graininess in the treble. Bass is gently softened at the very bottom but the rest of it is truly taut to create the impression that all of it is equally well controlled. But the impression is not fact. After some intense listening one might conclude that one would appreciate a bit more dynamics from kick drum for example. That’s a trade-off and real life. The most important thing. When reviewing a multi-purpose device like the Romulus, a reviewer must consider many things that can be skipped when dealing with other types. He has to sort out all the properties, decide which might be most important for potential buyers, which were important for its designers and which are important for the writer. The most important question I ask myself when listening to any device is: do I like it? It seems like a subjective approach but the only one that makes objective sense. Gathering experience from thousands of auditions (it’s been that many years), I always try to get to the point of ‘good’ sound as the one that’s close to what I hear at live concerts after taking into consideration one crucial correction. I must keep in mind that any recording is a totally different beast from a live performance. It can never sound the same. In this particular case I needed to ask additional questions: how did this device perform as CD player, as D/A converter, as CD player/preamplifier and finally as DAC/preamplifier. Plus there was one more question. How did USB hold up? The answer to the first question was very simple. I never thought that a machine at this price could offer such great performance. That’s a holistic assessment. Another deck I reviewed recently which performed as well was the Ayon Audio CD-3s but the Romulus still surprised with its finesse. Tonally Ayon’s sound was similar and it had more functionality. Ye it was the Romulus which had me spend long nights with headphones. Of course I realized that there was a slight emphasis in the bass and I knew that definition could be better. But I still loved its sound. The Austrian player delivers a bigger more open sound which should work in systems where Romulus might seems too warm or restricted. It was no coincidence that I compared Romulus to far more expensive players from Levinson and EMM Labs (and it might not have been a coincidence either that all three came from the US). They all shared a similar spirit or view on the music – on what’s more and what’s less important. All of them present instruments as 3D objects with the acoustic surrounding nicely formed but only where close to the soloist. All the rest is quickly gone. All of them are mostly about sustain and lower midrange emphasis which makes the sound even more palpable. Additional features of the Aesthetix are its USB input and volume control. It’s one of the very few digital players which needs no external preamplifier to sound very good. That’s because of its tonality. My version of the Ayon Polaris III reworked by Gerhard Hirt added more richness. But after some time I realized that I didn’t need it as the definition wasn’t as good as without it. The system without a preamplifier offered better selectivity but not necessarily a less rich sound. I checked with my Soulution 710 and Dan D’Agostino’s Momentum Stereo, two very different sounding amplifiers. The USB input was licensed from Gordon Rankin of Wavelength Audio. Gordon’s creation called Streamlength asynchronous USB is one of the best to market. Jim White of Aesthetix made good use of the licensed technology based on a programmable XMOS chip. It ensured that Romulus with a computer source delivered a very rich, colorful, dynamic sound even more 3-dimensional than CD and with timbre differences between instruments that were even clearer. On the other hand dynamics and resolution were slightly worse. In general the performance you get from CD vs. USB is the same as long as the latter is properly implemented. Summary. It didn’t take much effort to condense what I thought of Romulus. It was a very simple case really. Its sound was enchanting and involving. Its additional functions complemented the CD player perfectly because the USB input and volume control were cleverly done. It will not suit all systems though. If your system already lacks resolution, selectivity or delivers potent bass I would suggest looking for another player like Ayon’s CD-3s. If your system is well balanced or could use a bit of richness and weight, Romulus might be your personal Mount Everest. Review methodology. The test was an A/B comparison with A and B known. Aesthetix provides five small rubber footers which would seem to invite future owner to replace them with something better. I used three Finite Elemente CeraBalls and then placed everything on an Acoustic Revive RAF-48H platform. I used a Harmonix X-DC350M2R Improved Version power cable. The player ran with an Ayon Audio Polaris III preamplifier but during most sessions it drove directly either a Soulution 710 or Dan D’Agostino Momentum Stereo power amplifier. It performed better without a preamplifier. A Windows 8 computer with 128GB SSD, 8GB RAM and Jplay5 connected to the USB input via Acoustic Revive USB 5.0 PL cable.Design. Romulus from Aesthetix is a very good example of a fast growing subcategory of digital sources which combine in one box two or three different devices usually sold separately. In this case it’s a CD player, D/A converter with USB input and preamplifier. What’s missing over Austrian competitor Ayon Audio’s CD-3s are analogue inputs. You can order Romulus with or without CD transport. Without it becomes the Pandora. Romulus is quite large and solidly build. Usually CD players and DACs have their insides shielded by all manner of barriers to protect against EM and RF noise. When you look at Romulus you see that the transport, display microprocessor and two power transformers are enclosed in a shielded cage right behind the front but there are large cooling slots in this cage. The outer enclosure is built of thick aluminium panels whilst the cover has grating for better heat dissipation. This also allows you to look through it so the tubes and some circuitry are visible. The enclosure is quite large and rigid. The looks are a bit different. Usually the front panel is bigger than the casing or of the same size. Here the front panel fits into the shape created by the side panels, cover and bottom. The triangular push buttons are characteristic for Aesthetix and pick up on their triangle logo. In the middle of the fascia is a large blue display with alphanumeric LED modules. It’s divided into two sections. The smaller one indicates time info of a CD track or sampling frequency for a digital input. The larger one shows track number or volume. The latter only shows briefly with CD but constantly when a digital input is used. There are more blue LEDs to indicate repeat mode, phase and signal lock with an external transport. I guess these would look better if the shade of blue were the same as the display’s. I also think they’re too bright. The triangular controls can change inputs, activate mute, switch the display off and operate the CD player. Most of us are used to having the ‘open’ button next to the drawer. Aesthetix decided to place its ‘mute’ button there which is a bit counter-intuitive. The remote control also could use some work. It’s neither pretty nor very handy though it does control volume, phase and selects which part of the display is active.