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DK Designs VS.1 Reference Mk.III integrated amplifier Measurements

Sidebar 3: Measurements

Before performing any measurements on it, I preconditioned the DK Designs VS.1 Reference Mk.III by running it at 50Wpc (one-third the specified power) with both channels driven into 8 ohms for 60 minutes. The THD+noise remained at a highish 0.2% throughout this period, after which the heatsinks on the amplifier's sides measured around 55°C. The front third of the heatsinks remained cool, however, as no active devices are attached to these.

The fact that the phono stage has its own output, usually connected by jumpers to the Aux 1 line input, enabled me to…

Audio Physic Scorpio loudspeaker

There is a sweet spot in any manufacturer's lineup where minimum price and maximum performance meet. More expensive products in the line may offer higher fidelity, but the cost may not be commensurate with the improvement. For instance, VPI's HRX and Super Scoutmaster turntables cost more than their standard Scoutmaster model, and they perform better—but for my money, the sweet spot of VPI's line is the standard Scoutmaster, with or without such options as the outer clamp and Signature tonearm.

Back in the 1990s, the sweet spot of Audio Physic's line of loudspeakers was the Virgo II ($…

Audio Physic Scorpio loudspeaker Page 2

Before break-in—or after I'd gotten used to its sound, which is how those who don't believe in speaker break-in would characterize it—the Scorpio sounded somewhat tight on top and a bit brittle, mechanical, and stiff in the upper bass and lower mids. But after a week of heavy pounding, the speaker seemed to let go of its defensive posture and began delivering a purely musical picture.

But even in those first few encounters, the Scorpio did a very Virgo II–like thing: I'd be sitting in my listening chair working on my laptop while casually listening, and suddenly something in the…

Audio Physic Scorpio loudspeaker Specifications

Sidebar 1: Specifications

Description: Floor-standing, reflex-loaded loudspeaker. Drive-units: 1" soft-dome tweeter, two 6" coated paper-cone midrange units, four 7" coated paper-cone woofers. Frequency range: 30Hz–33kHz. Nominal impedance: 4 ohms. Sensitivity: 91dB/W/m.
Dimensions: 43" (1100mm) H by 8.1" (204mm) W by 15.2" (390mm) D. Weight: 59.4 lbs (27kg).
Finishes: light or dark maple, black ash, cherry. Ebony, rosenut veneers add $500/pair.
Serial Numbers Of Units Reviewed: 088A/B.
Price: $6495/pair. Approximate number of dealers: 26. Warranty: 10 years parts & labor…

Audio Physic Scorpio loudspeaker Associated Equipment

Sidebar 2: Associated Equipment

Analog Sources: Continuum Audio Labs Caliburn turntable; Graham Phantom, Continuum Cobra tonearms; Lyra Titan (stereo & mono versions), Clearaudio Concerto cartridges.
Digital Sources: Musical Fidelity kW SACD player, Alesis MasterLink BPT-modified hard-disk recorder.
Preamplification: Manley Steelhead, Einstein The Turntable's Choice phono preamplifiers; Musical Fidelity kWP preamplifier.
Power Amplifiers: Musical Fidelity kW monoblocks, Music Reference RM-200.
Loudspeakers: Vienna Acoustics Beethoven Concert Grand, Wilson MAXX2.
Cables…

Audio Physic Scorpio loudspeaker Measurements

Sidebar 3: Measurements

The Audio Physic Scorpio has a high specified sensitivity of 91dB/W/m. However, measured on its tweeter axis without the grille, the speaker appeared to have just above average voltage sensitivity, at an estimated 88.5dB(B)/2.83V/m. Its impedance (fig.1) stays between 4 and 6 ohms over most of the audioband, with a minimum value of 3.6 ohms at 93.5Hz. There is also a combination of 5.2 ohms and a –41° electrical phase angle at 78Hz, which might be taxing for optimistically specified power amplifiers, given that many kinds of music tend to have a lot of energy at…

Moscode 401HR power amplifier

Where does one start with the Moscode 401HR? With its design, which marries a tube driver stage to a MOSFET power output? Or perhaps with its designer, George Kaye, who refined Julius Futterman's OTL amplifier circuits before creating New York Audio Labs' original hybrid amplifier, the Moscode 300, in 1984?

Perhaps the most logical place to start is with the 401's "HR" designation, which honors the late Harvey "Gizmo" Rosenberg, a true audio original: champion of the Futterman OTL legacy, founder of New York Audio Labs, and patron and inspiration for George Kaye's forays into…

Moscode 401HR power amplifier Page 2

And I hate to say this, after telling you to make a ritual of installing the darn thing, but it's going to take about 40 hours for the 401HR to run in and start sounding its best. Don't worry—it sounds special from the get-go, just not as good as it's going to.

Heat the beat and the rest'll turn sweet
George Kaye knows his amp. Effortless ain't the half of it. When I pressed Play on Manu Katché's Neighborhood (CD, ECM 1896), Marcin Wasilewski's piano leapt out of the Dynaudio Special Twenty-Five loudspeakers. No, leapt isn't quite the word, but neither is thundered or roared or…

Moscode 401HR power amplifier Specifications

Sidebar 1: Specifications

Description: Two-channel, solid-state power amplifier with tubed input stage. Tube complement: choice of 6H30Pi, 6GU7, 6DJ8, 6922, 6FQ7, 5814, 7730, or 12AU7 (2 each). Tubes supplied: two 6H30Pi, two 6GU7. Maximum output power: 200Wpc into 8 ohms (23dBW), +300W into 4 ohms (21.8dBW), both channels operating. Voltage gain (tube dependent): ca 30–33dB. THD at full output (tube dependent; value with 6H30pi for V101 & 201): <0.15% at full power. Input impedance: 100k ohms. Noise (inputs shorted): <1mV. Power requirements: ca 120W at idle (1A), ca 960W at…

Moscode 401HR power amplifier Associated Equipment

Sidebar 2: Associated Equipment

Digital Source: Ayre C5-xe universal player.
Preamplifier: Conrad-Johnson CT5.
Power Amplifier: Musical Fidelity Nu-Vista 300.
Loudspeakers: Dynaudio Special Twenty-Five, Thiel CS2.4.
Cables: Interconnect: Shunyata Research Aries, Stereovox Colibri. Speaker: Shunyata Research Lyra, Stereovox Firebird. AC: Shunyata Research Anaconda & Orion.
Accessories: Audience adeptResponse power conditioner, Shunyata Research Hydra power-distribution system; OSAR Selway/Magruder equipment racks; Ayre Myrtle Wood Blocks.—Wes Phillips