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For me, the highlights of any audio show are finding a room with great sound and visiting it often throughout the show, to relax and absorb a wide range of great music. At the NY Audio Show in April 2012 in New York City, it was the room occupied by the Valve Amplification Company. There, I fell in love with the sound coming through the Signature Mk IIa line-stage preamplifier, and remembered that while I'd heard many VAC products at audio shows over the past two decades, and had enjoyed the sound every time, I'd never had a VAC product in my house. I requested a review sample.
Sidebar 1: Specifications
Description: Integrated amplifier. Analog inputs: one pair balanced (XLR), one pair unbalanced (RCA), one pair home theater (RCA). Digital inputs: 1 coaxial, 3 optical, 1 USB, 1 Ethernet (RJ45). Analog outputs (line level): fixed (RCA), variable (RCA). Headphone output: 6.3mm jack (front). Maximum output power: 150Wpc into 8 ohms (21.75dBW), 250Wpc into 4 ohms (21dBW). Maximum headphone output power, 270mWpc into 64 ohms. Frequency range: 5Hz–100kHz. S/N ratio: >100dB (no reference level given). Channel separation: >100dB. THD: <0.005%, 1kHz at 50W into…
3) Detailed, revealing, extended, uncolored reproduction of high frequencies with no loss of delicacy.
The Signature SE was the holy grail of high-frequency reproduction. Every region of the highs was detailed, undistorted, uncolored, and delicate. Normally, when I play a recording through a component with good HF reproduction, at some point, the music hits a frequency where the highs lose some of their delicacy or airiness, or take on a subtle brittleness. Not with the VAC. From the lower highs through the top of the audioband, the highs were detailed, extended, and "right," every bit…
Sidebar 2: Associated Equipment
Analog Sources: Acoustic Signature Wow XL, Pioneer PLX-1000, VPI Traveler turntables; Grado M+ Mono, Ortofon 2M Black, Soundsmith Carmen, Zu Audio DL-103 cartridges.
Digital Sources: Puresound A-8000 CD player; Halide HD, Line Magnetic LM 502CA DACs.
Preamplification: Blue Horizon BN:09-11-009, LFD, Schiit Mani, Soundsmith MMP3 phono stages.
Integrated Amplifiers: Line Magnetic LM518 1A, Rogue Audio Sphinx, Simaudio Moon Neo 340i.
Headphone Amplifier: Schiit Asgard.
Loudspeakers: DeVore Fidelity Orangutan O/93, Falcon and Rogers LS3/5As…
Sidebar 1: Specifications
Signature Mk IIa Tubed line-stage preamplifier. Tube complement: two 12AU7, two 8416, one each 7308, 6922, E88CC, ECC88, 6DJ8 (or 12DJ8 twin triodes). Inputs: 3 pairs RCA line input; 2 pairs balanced/RCA, selectable; 1 pair tape monitor (RCA); 1 pair cinema bypass (RCA); optional, 1 MM, 1 MC (or additional line input if optional phono stage not fitted). Outputs: 2 pairs single-ended (RCA), 2 pairs balanced (XLR, EIA studio standard, pin 2 hot), 1 pair tape (RCA). Gain: 12dB. Absolute phase: correct from all inputs to all outputs. Frequency response: flat over…
Sidebar 3: Measurements
I measured the Hegel H160 using my recently recalibrated Audio Precision SYS2722 system (see www.ap.com, and the January 2008 "As We See It"). Before performing any measurements on an amplifier, I run it for an hour at one-third its specified maximum power, which, thermally, is the worst case for an amplifier with a class-B or -AB output stage. I cut short this preconditioning of the H160 after 20 minutes, however, as the THD+noise, which had been just 0.00315% with the amplifier cold, had risen to 0.83%. The chassis was mildly warm, at 92.2°F (33.4°C), but the…
Sidebar 2: Associated Equipment
Analog Sources: Rega Research Planar 3, VPI TNT IV turntables; Immedia, Syrinx PU-3 tonearms; Clearaudio Virtuoso Wood, Koetsu Urushi phono cartridges.
Digital Sources: Creek Destiny, Lector CDP-7T CD players.
Preamplification: Vendetta Research SCP-2D phono stage, Audio Valve Eklipse line stage, Audio Research SP20 preamplifier.
Power Amplifiers: Audio Research Reference 75.
Loudspeakers: Epos M16i, Monitor Audio Silver RS6, Nola Viper Reference III.
Cables: Interconnect (all MIT): Magnum M3, MI-350 CVTwin Terminator, MI-330SG…
Sidebar 3: Measurements
I measured the VAC Signature SE's electrical performance with my Audio Precision SYS2722 system (see www.ap.com and the January 2008 "As We See It"). The cramped space on my test bench meant that I had to place the audio enclosure atop the power supply, but I separated them with 3" spacers.
Looking first at the performance of the line inputs, the left channel's maximum gain into 100k ohms was the same in balanced and unbalanced modes, at 10dB rather than the specified 12dB. This will not be an issue in practice. Feeding the preamplifier an unbalanced…
Robert Lighton's career has included stints as a clothing manufacturer, a maker of expensive wristwatches, and, most recently, a designer and manufacturer of high-end furniture, examples of which grace the homes of Richard Gere, Kevin Kostner, and Renee Zellweger. It was during the latter occupation that Lighton—whose introduction to hi-fi and record collecting came while growing up in Kansas City—began to consider high-end audio as a professional pursuit. He was impressed with playback gear from Audio Note UK, and thought he might succeed in representing them in New York City—but Robert…
Editor: We are really happy to read this review, our first in Stereophile. We are particularly happy to have the quality of our DAC confirmed. We have worked really hard on designing a DAC with very low noise and very low jitter levels, without going through the roof on cost. Obviously, we needed to make a few sacrifices; eg, as John Atkinson mentions, on 88.2kHz over USB to meet the price target. But the lack of asynchronous USB is intentional, as we believe we can achieve even lower jitter levels with our solution.
We also read that Herb Reichert was missing an extra analog input. We…