Setup
I positioned the 160Ms on Grand Prix…
search
One very cool feature is the 160M's tube-hours counter, just below the three toggles. I checked it frequently while completing the 400–600 hour break-in process that ARC had begun. Many makers of tube amps caution against turning on their amps when they're not connected to speakers. Although Dave Gordon had told me that I could break in the 160Ms' tubes without connecting the amps to my speakers, ARC later sent me two huge, heavy brass resistors. I connected these to the 160Ms' speaker terminals, to ensure that break-in would occur evenly.
Sidebar 1: Specifications
Description: Fully balanced, class-AB tubed monoblock power amplifier. Tube complement: four KT150 (output), two 6H30 (gain stage). Inputs: unbalanced (RCA), balanced (XLR). Three sets of speaker output taps: 4, 8, 16 ohms. Output power: 140W continuous, 20Hz–20kHz (21.5dBW). Frequency response: 0.5Hz–110kHz, –3dB at 1W. Power bandwidth: 5Hz–70kHz, –3dB. Input sensitivity: 2.4V RMS balanced for rated output (25.5dB gain into 8 ohms). Input impedance: 300k ohms balanced, 100k ohms single-ended. Output regulation: ca 0.6dB into 16 ohm load to open circuit (damping…
Sidebar 2: Associated Equipment
Digital Sources: dCS Paganini SACD/CD transport & Scarlatti clock & Vivaldi DAC & Network Bridge; Linksys router with two TP-Link gigabit Ethernet media converters, multimode duplex fiber-optic cable; external hard drives, USB sticks, iPad Pro.
Preamplifier: Audio Research REF 6.
Power Amplifiers: Dan D'Agostino Master Systems Progression monoblocks, Pass Laboratories XA200.8 monoblocks.
Loudspeakers: Wilson Audio Specialties Alexia 2.
Cables: Digital: AudioQuest Diamond, Wireworld Platinum Starlight Cat8 (Ethernet); Nordost…
Sidebar 3: Measurements
This Audio Research amplifier presented a measuring challenge. It has balanced and single-ended inputs, two different modes of operation, and three output-transformer taps. It is therefore 12 different amplifiers. I performed full sets of tests using its balanced input in both Triode and Ultralinear modes from the 4 ohm and 8 ohm output taps, then repeated some of the tests using its single-ended input and the 16 ohm tap. After I installed the tubes, I used the Tube Monitor button on the front panel to make sure all was well with the KT150 output tubes—all four…
How many who love Bernstein's "popular" music—everything from On the Town and West Side Story to the final Arias and Barcarolles—have actually spent time with his three "serious," gravely introspective symphonies? Perhaps the best way to do so in up-to-date sound is to dive into Warner Classics' superbly annotated and recorded Bernstein: The 3 Symphonies from Antonio Pappano and the Orchestra, Chorus, and "Voci Bianche" of the Accademia Nazionale di Santa Cecilia. Together with excellent soloists, Pappano presents the three symphonies on two CDs, with options of a 24/96 download and hi-rez…
I am finding hard to grasp that it is almost 50 years since I first went to a hi-fi show. That show, held at London's Olympia exhibition center, was notable both for Yamaha's launch of a loudspeaker with a speaker diaphragm shaped like a human ear, and for being the first time I saw the drop-dead gorgeous Transcriptors Hydraulic Reference turntable, which was later featured in the film A Clockwork Orange. The most recent show I attended was AXPONA, held last April in the Chicago suburb of Schaumburg. There I saw no ear-shaped drive-units, but the final room I visited featured sound that the…
Regarding the Centaur II 500's reproduction of low frequencies, even when the speaker had relatively limited extension—such as the Dynaudio Special Forty stand-mount I reviewed in September 2018—there was a surprisingly satisfying combination of weight and control. For example, when Jaco Pastorius drops down to a detuned low F and C at the start of "Overture—Cotton Avenue," from Joni Mitchell's Don Juan's Reckless Daughter (AIFF file, 24-bit/192kHz needle drop from LP, Asylum K63003), I didn't feel I was missing too much music with the Dynaudios. (And yes, I know—no one but a reviewer is…
Sidebar 1: Specifications
Description: Solid-state stereo power amplifier. Inputs: 1 pair unbalanced (RCA), 1 pair balanced (XLR), 1 pair Direct (XLR), 12V trigger (3.5mm jack), control (USB). Outputs: 2 pairs speaker binding posts. Power output: 500Wpc into 8 ohms (27dBW), 1000Wpc into 4 ohms (27dBW), 1600Wpc into 2 ohms (26dBW). Frequency response: 10Hz–100kHz, +1/–0.5dB. Voltage gain: 26dB (balanced & RCA), 14dB (Direct). THD+N: <0.05% at 1kHz, rated power. Noise: <70µV (500kHz bandwidth). Signal/noise: 116dB ref. 250W. Input impedance: 100k ohms unbalanced, 200k ohms…
Sidebar 2: Associated Equipment
Analog Source: Linn Sondek LP12 turntable with Lingo power supply, Linn Ekos tonearm, Linn Arkiv B cartridge.
Digital Sources: Roon Nucleus+ music server; Ayre Acoustics C-5xeMP universal player; PS Audio PerfectWave DirectStream D/A converter; Ayre Acoustics QA-9 USB A/D converter.
Preamplification: Channel D Seta L phono preamplifier.
Power Amplifiers: Bricasti Design M15, Lamm Industries M1.2 Reference (monoblocks).
Loudspeakers: Dynaudio Special Forty, Tidal Audio Akira, Wilson Audio Specialties Alexia Series 2.
Cables: Digital:…
Sidebar 3: Measurements
I measured the Constellation Performance Centaur II 500 using my Audio Precision SYS2722 system (see the January 2008 "As We See It"). Before I test an amplifier, I precondition it with both channels driving a 1kHz tone at one-third power into 8 ohms for an hour. At the end of that time, the Constellation's enclosure was hottest toward the rear of the top panel, at 101.3°F (38.5°C).
The voltage gain at 1kHz from the speaker terminals into 8 ohms measured 25.9dB for both balanced and unbalanced signals, and 12dB for the Direct input. All sets of inputs…