Rega Research DAC-R D/A processor
Okay, I jest about that last part.
Anyway, a couple weeks before recording started, Rega Research's new DAC-R ($1195) arrived for review, presenting me with a chance to compare what I was hearing live in the studio with our recorded results played back in the listening room. And because the group was recording a second set of songs at Painted Sky, another studio nearer the coast, in Harmony, California (footnote 1), it was also an opportunity to hear how the same people sounded when recorded in two different places by two different sets of ears at about the same time. Every few days, I received a CD with the latest mixes from Painted Sky, which I could compare with what we were getting here at Dog Bark. I thought, What could be better than using live music as a reality check for a DAC?
Well, it got complicated. Although I and the other engineer were both trying to capture the "reality" of the same musicians and instruments in a live space, it quickly became apparent that there's more than one artistically valid way to do this.
The same is true, in a more subtle way, of designing a DAC. Given that the final recording document the listener buys is the final "reality," DAC designers still have some room in which to make choices and home in on the sound they seek. And as in the studio, where choosing the right microphone for a voice or guitar is an art, the designer must decide between various chipsets, filters, power-supply designs, clocking technologies, and so on, to fine-tune the sound of his or her DAC.
In our sessions, the choices of mikes and mixes made in the studio forever changed the reality recorded, but having Christine singing right there, 6' away, did help me hear just how well a given DAC was reproducing her voice. More about this later.
Outwardly, the DAC-R looks very similar to Rega's previous DAC, called simply the DAC and reviewed by Sam Tellig in the May 2011 issue. However, changes have been made: The case is bit longer, which permits a better layout for the power supply, and Rega tells me they've made minor changes in the power connector and improvements in the firmware and hardware operation at 176.4kHz, as well as to the power-up process. The price has risen by $200, and you can now control the input and filter selections via remote control.
The most significant change for computer-audio users is that the DAC-R has an XMOS-based, 24/192 USB asynchronous input. In his review four years ago, Sam quoted Terry Bateman, Rega's electronics design engineer, as saying that Rega didn't see USB "as a high-tier audio interface." Things changethe USB input stage now feeds the optical and coaxial input stages via an isolating transformer, totally isolating the DAC from the host computer.
Inside are twin "Buffer-Stage-Driven" Wolfson WM8742 DAC chips, but no upsampling. Bateman explained to me that "The plan was to keep the signal path as straightforward as possible and not run the DAC ICs faster than the incoming sample rate by means of a rate converter, thus complicating things." He said that the same mo' simple, mo' betta approach goes for the clean analog signal path: "I used the same discrete output amplifier I used in the Saturn and Apollo [DACs], giving a drop of old-school discrete transistor mojo." Bateman also said, "I have used good-quality electrolytic and film capacitors in the analog signal path. I paid attention to the power supplies for all stages, along with the integrity of the data and clock signals running throughout the unit." In fact, there is a power supply for the control microcontroller, separate from the digital and analog audio stages.
Rega's DAC-R measures 8.4" wide by 3.1" high by 12.5" deep and weighs 8.8 lbs, and feels as dense as a block of stone. When tapped, its case does not ring anywhere. A slight depression runs down the center of the top plate from front to back, as if someone had pressed down a rolling pin lengthwise and gently rocked it back and forth. So although the DAC-R is essentially a rectangular box, it has pleasantly sculpted feel.
Four large rubber feet on the bottom plate raise the DAC-R about half an inch above whatever surface it sits on. It ran warm but never hot in my cabinet, where its case of aluminum, steel, and glass projected an aura of no-nonsense refinement. On the DAC-R's faceplate of highly reflective glass are three silver buttons in a row, an IR sensor, and three sets of small red LEDs. The power button, on the left, has a solid mechanical feel when engaged; the other two buttons require only a slight, brief tap. The center button selects among three filters (see below). To the right of it is a column of four LEDs indicating the sample rate the DAC-R is locked to: 44.148, 88.296, 176.4, or 192kHz. To the right of those is the Input button, surrounded by an arc of six LEDs indicating which input has been selected (USB, 14), and Input Locked.
On the rear panel, from left, are: the 24-bit/192kHz USB input, two 24/192 optical inputs, two 24/192 S/PDIF coaxial inputs, an optical digital output, an S/PDIF coaxial output, and left/right analog RCA jacks. On the right are the fuse bay and the IEC C13 power receptacle. This is a no-frills DAC with no balanced connections, AES/EBU input, DSD processing, or headphone jack.
Also included is a remote control that, though festooned with buttons, is of little use. Only one of its 18 buttons, the input selector, controls anything on the DAC-R. Rega's optional Solaris system remote ($125) includes a button for switching among filters, along with a ton more buttons that also have nothing to do with the DAC-R. I suppose this encourages "system" purchases, but it makes no sense for the user whose only Rega component is a DAC-R. A dedicated remote with controls for only the DAC-R's most important functions, Input and Filter selection, would be much better, and probably cheaper to make.
I love seeing a DAC with a reconstruction filter selectorit lets the listener fine-tune the trade-offs of each slightly compromised approach. The Rega DAC-R has three choices of Filter setting, but each of these changes depending on sampling rate. For sampling rates of 48kHz and under, they are: Filter 1) Linear phase half-band, 2) Minimum phase half-band, and 3) Minimum phase apodizing. For medium and higher sampling rates (88.2192kHz), the filters are: 1) Linear phase soft-knee, 2) Minimum phase brickwall, and 3) Linear phase apodizing.
Footnote 1: Yes, this is actually the name of the town, in which one finds little more than the well-equipped Painted Sky Recording Studio and a pottery shop. Population: 18. Perfect for music, yes?