Devialet D-Premier D/A integrated amplifier Phono Stage
When I reviewed this extraordinary French amplifier last January ($15,995), I ran out of space and time before I could audition and measure its performance via its phono inputs. That is the subject of this Follow-Up. My sample of the D-Premier was serial no.00965, hardware v.4.1.1, running firmware v.5.6.0.
Like almost all of the D-Premier's input and output jacks, the two RCAs used for the first line-level input can be reassigned in software to handle phono signals. You visit the Configurator page on the Devialet website and, using the interactive illustration of the D-Premier's rear panel (fig.1), customize the input to suit your LP player.
The options are: moving-coil or moving-magnet, each with ranges of gains and capacitive and resistive loadings; stereo or mono; L/R balance; 1953 or 1976 startup RIAA curve; and a sample rate of 96 or 192kHz (fig.2). (The D-Premier digitizes its phono inputs and applies the RIAA de-emphasis in the digital domain.) Once the options have been chosen, the website widget creates a text file, dp_cfg.txt, which can be downloaded and copied to an SD card that slots into the D-Premier's rear panel. When you next turn the amplifier on, it reads the text file and reassigns its inputs accordingly; as it does so, it shows on its top-panel display the message "Custom Config."
To test the phono stage, I set the D-Premier's third pair of RCA jacks to be either a fixed-level pair of analog outputs, or one of the jacks to be a fixed-level S/PDIF output. (Both outputs can also be variable level, adjusted with the remote control's volume knob; the S/PDIF sample rate needs to be set independently of the A/D converter's sample rate.) I examined the phono stages in both the analog and digital domains using Stereophile's loan sample of the top-of-the-line Audio Precision SYS2722 system (see www.ap.com and the January 2008 "As We See It").
To choose the gain appropriate for your cartridge, you move the Max Level slider on the Configurator. For MM, setting this to "5.0mV" gave a measured gain at the Preamp output jacks of 45.3dB (45dB is specified); setting it to "10.0mV" gave 39.5dB (39dB specified). For MC, setting this to "500µV" gave a measured gain of 62.5dB. Which gain you choose will be critical, as you need to avoid overloading the D-Premier's A/D converter. With the MM input set to "5.0mV," a 1kHz tone at 5mV resulted in a digital-domain signal at 2.18dBFS. For my Linn Arkiv B MC cartridge, I had to set the Max Level to "1500µV"; with typical LPs, this resulted in digital peaks of around 3dBFS.
The D-Premier's phono input preserved absolute polarity (ie, was non-inverting) in both MM and MC modes. Set to MC, the highest choice of input impedance was 460 ohms; I measured 461 ohms. In MM mode, the highest input impedance is unhelpfully called "High." I measured 14k ohms at 20Hz and 1kHz, dropping slightly to 12k ohms at 20kHz. This might bit too low for Shure cartridges, which like to see 68k ohms.
Fig.3 shows the D-Premier's RIAA error, set to 192kHz sampling and the 1953 curve. The channels are superbly well matched, and the de-emphasis is perfect up to 10kHz, better even that that of the Liberty B2B-1, which was the best I had measured until now. The level at the preamp outputs then starts to roll off, reaching 1dB at 20kHz and 6dB at 50kHz. To my surprise, changing the sample rate to 96kHz gave the same result from the analog outputs, without the expected brick wall at 48kHz. Changing the RIAA curve to "1976," which I had assumed would apply the specified high-pass rolloff of 3dB at 20Hz also made no change in the measured response. Perhaps the 1976 revision of the RIAA curve will be implemented in a future firmware release.
Channel separation (not shown) was good, at >80dB below 1kHz, and noise was very low in MM and MC modes. The overload margin was good, at an even 17dB across the audioband in MC mode (set to "500µV") and 20dB in MM mode (set to "10.0mV"). One peculiarity: At 20kHz, some sort of soft limiting seemed to be in effect; I couldn't get the input to overload. Distortion was low, at typically 0.06%, and dominated by the subjectively benign second harmonic (fig.4), though this digital-domain spectrum does reveal some low-level, higher-order harmonics. Intermodulation distortion was also low (fig.5).
As well as auditioning the D-Premier's phono stage, using my usual Linn analog front end of Sondek LP12 turntable, Ekos tonearm, and Arkiv B cartridge, I used the amplifier to rip some LPs, using its digital output to feed the S/PDIF input of a Metric Halo ULN-2 FireWire interface and recording the data as AIFF files on my MacBook Pro. Perhaps I endanger my Audiophile Reviewer badge by admitting this, but I could hear no substantive difference between the D-Premier's phono stage set to sample at 96kHz or at 192kHz when playing LPs. Because the Metric Halo will accept data up to only 96kHz, that's the rate at which I performed my rips. However, I did check that the D-Premier's digital output correctly output data at 192kHz by connecting it to the Audio Precision's S/PDIF input. This also allowed me to confirm that all 24 bits in the Devialet's digital output are active.
As for the sound of the D-Premier when used to play LPs, it was clean, clean, cleannot in the sense of sterile, but in the sense that there was very little coming between the music and me. There was a delightful delicacy to Radka Toneef's fragile soprano in Jimmy Webb's "The Moon Is a Harsh Mistress," from her Fairytales (Odin LP03), yet with clarity and weight given to the accompanying acoustic piano. In "Die Tänzerin," from Ulla Meinecke's Wenn Schon Nicht für Immer, dann Wenigstens für Ewig (German RCA 426124), the absence of grunge let me hear the decaying reverberation of her voice at the end of each phrase with a clarity I had not experienced before. Back in the day, I used to time how long I could hear the decay of the reverb, and it was the rare playback system that let me get past 2 seconds or so. The Devialet's resolution and low noise revealed a full 3 seconds' worth of reverberation.
The inevitable ticks and pops on my old LPs also seemed more tidily handled, less sonically obtrusive, by the D-Premier than by a conventional analog phono preamp, the Liberty B2B-1, feeding the Ayre Acoustics QA-9 A/D converter, which I reviewed last November.
The Devialet D-Premier's phono stage sounds and measures up to the superb standard set by the amplifier's performance with line-level analog and digital signals. As I write these words, the UPS man is on his way to pick up the D-Premier to return it to the distributor. I'm already missing it!John Atkinson