I performed a full set of measurements on the C-J Premier Eleven A, but I'll show just a couple here. In the measurements accompanying WP's review of the original Eleven amplifier, Tom Norton found a suspicious-looking distortion spuriae trace (fig.1) that implied the amplifier suffered from crossover distortion. It appeared that the culprit was the circuit that drove the biasing LEDs; the A revision of the amplifier was said to have been fixed in this regard. Fig.2, taken under much the same conditions as fig.1, shows…
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Sidebar: Eleven A Measurements (from September 1995, Vol.18 No.9):
Sidebar: VAC Comparisons
Wes Phillips compared the Premier Eleven A with the VAC PA80/80 in March 1996 (Vol.19 No.3)
My longtime reference power amplifier, the Conrad-Johnson Premier Eleven A, costs $700 more than the Valve Amplification Company PA80/80 and provided an instructive contrast to it. While retaining many of the tube virtues, the Premier Eleven A sounds even less like a classic tube product than the VAC does—it's more extended at the frequency extremes, which also gives it a tauter, leaner sound. Its deeper, slightly more controlled bass lacks the midbass punch that…
My father could not resist buying electronic and photographic gear. As soon as he heard about a new Polaroid camera, or a new weather radio, tape recorder, or color television, he'd go shopping. He'd be even more eager to buy an updated version of what he already had, particularly if this meant there was a story to tell. He'd buy one for himself, and sometimes he'd give me and my three brothers one of our own for a birthday or Christmas gift. (I often thought he took more pleasure from giving to us than he did from getting his own.)
Dad would have loved the new Mark Levinson No.334…
Space doesn't allow a full description of the design features shared by the Nos.331 and 334; for that, consult the original review in Vol.19 No.1. Briefly, the dual-mono configuration features large independent power supplies with two 801VA toroidal transformers, one for each channel, oriented to cancel stray magnetic fields; and balanced circuit technology derived from the No.33 and No.33H reference monoblocks. The circuitry includes two triple-bypassed, 44,000µF, low-ESR electrolytic filter capacitors per channel; a soft-clipping circuit to reduce the audible effects of amplifier clipping…
Don Dorsey's use of synthesizer chords in "Ascent," from Time Warp (Telarc CD-80106), thrilled me again. Although I'm familiar with this piece, I had not anticipated how the much the Salon/No.334 combination would intensify my emotional reaction to the music. The sledgehammer bass and transparent highs sent me on an emotional roller coaster, as Dorsey's synthesizer erupted out of total black silence with a run of bells, pulses, whooshes, and high-pitched tones like those produced by running your finger over the rim of a glass—all sweeping back and forth across the soundstage at what seemed…
Sidebar 1: Specifications
Description: Solid-state dual-mono power amplifier. Frequency response: 20Hz-20kHz, ±0.1dB. THD: 0.5% (FTC). Power output: 125Wpc into 8 ohms (21dBW), 250W minimum continuous into 4 ohms (24dBW), 500Wpc minimum continuous into 2 ohms (27dBW), 500W into 8 ohms bridged (27dBW). Input impedance: 100k ohms balanced, 50k ohms single-ended. Voltage gain: 26.8dB. Input sensitivity: 130mV for 2.83V output, 1.44V for full output. Output impedance: ±0.05 ohms, 20Hz-20kHz. Damping factor: >800, 20Hz-20kHz into 8 ohms. S/N: >80dB (ref. 1W). Power consumption:…
Sidebar 2: Madrigal's No.331.5 Update Kit for the No.331
Having heard the No.334's strong bass response and dynamic contrasts, I couldn't wait to try Madrigal's MLC780 VG No.331.5 Update Kit on my own No.331 dual-mono amplifier. At $1950 it is an expensive modification, especially when you consider that the difference in retail cost between the No.334 and the discontinued No.331 is only $1000. Madrigal claims that the two cyanate-ester voltage-gain boards account for most of this cost. Besides these PCBs, the kit supplies a new black-anodized "No.331.5" nameplate for insertion into the…
Sidebar 3: Associated Equipment
Analog sources: Linn Sondek LP12 turntable with Lingo power supply, Ittok tonearm, Spectral moving-coil cartridge.
Digital source: Krell MD-1 CD transport, Adcom GDA-700 processor.
Tuners: Day-Sequerra FM Reference Classic, Rotel RH-10, Fanfare FM-1, Magnum Dynalab MD-108/Model 205 Sleuth RF amplifier, Myryad T 100.
Preamplifiers: Krell KBL, Mark Levinson ML-7A with L-2 phono section, Duntech MX-10 head amplifier.
Power amplifiers: Mark Levinson No.331, No.334s (2), Bryston 4B-ST (stereo), Bryston 7B-ST (monoblocks).
Loudspeakers: Snell Type…
Sidebar 4: Measurements
A complete set of measurements of the Mark Levinson No.334 was made in the balanced configuration. Selected readings were also performed in unbalanced mode. Unless otherwise noted, the results here refer to balanced operation.
Following its one-hour preconditioning test, the Mark Levinson's heatsinks were hot, but could still be touched without discomfort. The amplifier's voltage gain into 8 ohms measured 27dB, balanced or unbalanced. The input impedance measured 98k ohms balanced, 50.7k ohms unbalanced. The DC offset was a very low 1.5mV in both channels…
Fig.3 plots the small-signal THD+noise percentage against frequency. This result is typical of well-designed solid-state amplifiers. The 1kHz, THD+noise waveform at an output of 40W into 4 ohms is shown in fig.4. (The distortion is largely obscured by noise at the lower power readings we usually use for this measurement.) The second harmonic dominates, but the waveform's slight triangularity indicates the presence of higher-order harmonics. This is more pronounced into a 2 ohm load, less so into 8 ohms. (Neither of the latter is shown.)
Fig.3 Mark Levinson No.334, THD+noise (%) vs…