Against the MF Primo
The Tube Mk.II reminded me most of the Musical Fidelity Primo. It costs $6400 more, not including The Remote, but for that money you get another level of sonic refinement: a step up in transparency, and a more appropriately compact, solid, and densely…
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The sound of the Einstein's top end through the stock tubes was slightly forward, though it still lacked the darTZeel's air and resolution; if your system is already bright, don't expect The Tube to complement it. It might even make the sound worse, though in that case, replacing some tubes might be the solution.
Sidebar 1: Specifications
Description: Tubed, two-channel line preamplifier. Tube complement: (18) E88CC/6922, (1) ECC82/12AU7. Frequency range: 2Hz–300kHz. Maximum output: N/A. Output impedance: 50 ohms. Input impedance: not given. Distortion: <0.05% at 1kHz, 1.5V output; <0.1% at 1kHz, 1.5V output, 100 ohm load. Signal/noise: >95dB (no reference level quoted). Input sensitivity for full output: not given. Overload margin: 7V. Channel separation: not given.
Dimensions: 16.8" (431mm) W by 6.2" (158mm) H by 15.3" (393mm) D. Weight: 33 lbs (15kg).
Finish: Black and chrome.…
Sidebar 2: Associated Equipment
Analog Sources: Continuum Audio Labs Caliburn, Cobra, and Castellon turntable, tonearm, and stand; Audiostone Pythagoras turntable; Graham Engineering Phantom II, HiFiction Thales AV tonearms; Ortofon A90, Lyra Titan i, Miyajima Premium BE (mono) cartridges.
Digital Sources: Playback Designs MPS-5 SACD/CD player-DAC, Camelot Roundtable Anagram Technologies DAC, BPT-modified Alesis Masterlink hard-disk recorder, Benchmark ADC1 A/D converter, Meridian Sooloos music server.
Preamplification: Einstein The Turntable's Choice, Boulder 2008, Esoteric E-03…
Sidebar 3: Measurements
I used Stereophile's loan sample of the top-of-the-line Audio Precision SYS2722 system (see the January 2008 "As We See It" and www.ap.com) to examine the Einstein The Tube Mk.II's measured behavior; for some tests, I also used my vintage Audio Precision System One Dual Domain. Not having seen Michael's review when I performed the measurements, I used the CD input with the stock tubes. (All the inputs are nominally identical.)
Assessed at its balanced outputs, the Einstein offered the same maximum gain—a sensibly moderate 12dB—for both balanced and single-…
It's been a while since I've had a classic amplifier in my system, and McIntosh Laboratory's MC275 is as classic as they come. Introduced in 1961 as the "powerhouse" of that era's newfangled stereo tube amps (two 75W amplifiers in one chassis!), the MC275 retained its position as the amplifier to own—challenged only, perhaps, by Marantz and a few others—until 1970, when it fell prey to the widespread wisdom that transistors were king and tubes were dead, and the model was discontinued. The MC275 briefly returned in 1993, in a limited "Commemorative" edition to honor the late Gordon Gow,…
Although my doctorate is in political science, and my training—in physics and engineering—is at best scanty, these design changes, all told, didn't strike me as quite transformational. As I watched those 11 tubes begin to glow, I wondered: Would this new MC275 sound like a just-slightly-revved-up version of a half-century-old tube amp, oozing midrange magic but rolled off at the top and bottom—or like a warm but zippy modern music-making machine?
Setup
I did all my listening through Revel's Ultima Studio2 speakers. The digital source was a Krell Evolution 505 SACD/CD player; for…
The MC275 was not without weaknesses. In general, very low frequencies tended to sound a little more like bass tones than like notes played on an instrument. The big bass drum at the beginning of "Nuages," on the James Carter CD, didn't have quite the oomph in the attack, or quite the persistence in the decay, that it should. On 88 Basie Street, the notes from Cleveland Eaton's bass were distinct, but the plucking was too soft. Similarly, on Dolphy's Out to Lunch, Richard Davis' bass, though once again its notes were very clear, lacked the wood that this album, and especially this reissue,…
Sidebar 1: Specifications
Description: Two-channel, tubed stereo (switchable to parallel mono operation) power amplifier. Tube complement: four KT88, three 12AX7A, four 12AT7. Inputs: 1 pair single-ended (RCA), 1 pair balanced (XLR). Loudspeaker outputs: separate gold-plated, 5-way binding posts for 4, 8, and 16 ohms. Preamp output: 1 pair single-ended (RCA). Inputs: 1 pair balanced (XLR), 1 pair single-ended (RCA). Output power: 75Wpc (18.8dBW) into 4, 8, or 16 ohms (stereo), 150W into (21.8dBW) 2, 4, or 8 ohms (mono). Frequency response: 20Hz–20kHz, +0/–0.5dB; 10Hz–70kHz, +0/–3dB.…
Sidebar 2: Associated Equipment
Analog Source: VPI Classic turntable & JMW Memorial tonearm, Lyra Delos cartridge.
Digital Source: Krell Evolution 505 SACD/CD player.
Phono Preamplifier: Nagra BPS (battery-powered).
Integrated Amplifier: Krell FBI (mainly used as line stage).
Loudspeakers: Revel Ultima Studio2.
Cables: Nirvana interconnects & speaker cables, Nordost CAST interconnect (between Krell components).
Accessories: Bybee Technologies Signature Model Power Purifier (not power amp), Black Diamond Mk.4 Racing Cones, Mapleshade pucks, VPI HW-19 record-cleaning…
Sidebar 3: Measurements
To perform the measurements on the McIntosh MC275, I mostly used Stereophile's loan sample of the top-of-the-line Audio Precision SYS2722 system (see the January 2008 "As We See It" and www.ap.com); for some tests, I also used my vintage Audio Precision System One Dual Domain. The MC275 has four output terminals for each channel, one labeled "Common," the others "4," "8," and "16." I performed a complete set of measurements from each output transformer tap using the balanced inputs, and repeated some of the tests using the unbalanced input jacks.
With…