This very low noise floor contributed to excellent linearity performance (fig.4). With 16-bit input data (top…
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However, note that at lower frequencies, the increase in word length has unmasked a couple of power-supply components, at 120Hz and 240Hz. I tried different grounding arrangements to eliminate these, without success—but at around -130dBFS, their presence will have zero subjective effect. Changing the data to represent a -1LSB DC offset gave a smooth, low noise floor (not shown), again with some content noticeable at the power-supply frequencies but without any idle tones present.
Distortion levels were negligible. Spectral analysis of the No.360's output while it decoded data representing a 50Hz sinewave at 0dBFS (fig.7) revealed traces of second and third harmonic, but at almost 100dB down from full-scale these will be benign. This graph was taken from the balanced output; from the single-ended output, the third harmonic stayed where it was but the second harmonic rose to a still-negligible -94dB (0.005%). The Levinson's performance was equally good on the punishing full-level high-frequency intermodulation test. The 1kHz difference tone was almost 90dB down from…
Kalman Rubinson wrote about the Mark Levinson No.360S in October 2003 (Vol.26 No.10):
I reviewed the Mark Levinson No.360 D/A converter in the December 1999 Stereophile (Vol.22 No.12), in the company of DACs from mbl and Burmester, and found that the ML held its own against the two much more expensive models. Those other two went back to their providers, with my gratitude, but the No.360 took up residence in my system as the reference against which new contenders would be graded. Its multiplicity of input connector types, 24-bit/96kHz capability, programmability, and doggone satisfying…
Sidebar: Kalman Rubinson's 2003 Associated Equipment
Digital sources: Meridian Reference 800/861 DVD-Audio player, Sony XA-777ES SACD player.
Preamplification: Sonic Frontiers Line-3 preamplifier.
Power amplifiers: Bel Canto eVo6, Sonic Frontiers Power-3, Classé CAM-350 monoblocks.
Loudspeakers: Revel Ultima Studio.
Cables: Interconnects: AudioQuest Anaconda & Python, both balanced; Cardas Cross, unbalanced. Speaker: AudioQuest Gibraltar. AC: PS Audio Lab, JPS Aluminata—Kalman Rubinson
It was back in the mid-'70s that David Berning made a name for himself in the Baltimore-Washington area as an avant-garde designer—someone with a truckload of fresh ideas about tubes. At the time, though Audio Research was starting to crank out pretty decent amplifiers, tube design was pretty much reduced to a rehash of the Williamson circuit and the Dynaco mod of the month.
Murray Zeligman introduced me to Dave Berning's creations. I remember driving out to Dave's house in Potomac one evening to look over an EA2-150 amp (which I later purchased). There was a cavernous basement filled…
But nothing is without its price. Because the screen grid is farther away from the cathode than the control grid, it is much less effective in controlling plate current. A 300V drive signal is required for the screen grid to take control, meaning that you end up with another amplifier just to drive the output stage. A total of four Russian-made 6SN7 dual-triodes per channel generate the requisite voltage gain. All of the gain stages are fully balanced, and the inputs accept either XLR balanced cable or unbalanced RCA terminations. A switch on the back of the amp allows changeover from…
Listening impressions
The Berning proved to be one of those amplifiers whose sonic performance was hard to categorize, though not for the obvious reason. Amps that impose a minimal tonal signature on the sound are sonic chameleons, taking on the personality of the front end or speaker load. That was not the case with the Berning. It clearly brought its personality to bear on the music, but in a system-dependent manner. With a favorable front end and load, only the tip of the iceberg shone through. But with less than sympathetic matching equipment, it asserted itself in a manner neither…
The Berning proved to be one of those amplifiers whose sonic performance was hard to categorize, though not for the obvious reason. Amps that impose a minimal tonal signature on the sound are sonic chameleons, taking on the personality of the front end or speaker load. That was not the case with the Berning. It clearly brought its personality to bear on the music, but in a system-dependent manner. With a favorable front end and load, only the tip of the iceberg shone through. But with less than sympathetic matching equipment, it asserted itself in a manner neither…
Sidebar 1: Measurements
Following its one-hour preconditioning test, the Berning EA-101 was quite hot to the touch in the region above its 16 tubes. Its input impedance measured just over 91.5k ohms into its unbalanced input, just under 191.5k ohms into its balanced input. I measured zero DC offset in both channels. The Berning inverted polarity, a positive impulse at its input resulting in a negative impulse at the output.
Beyond these basic characteristics, assessing the performance of the Berning involved a large array of measurements, made necessary by the amplifier's…
Figs.7 and 8 provide another look at this from a different perspective. The THD+noise vs frequency curve in fig.7 shows the results for a constant 8 ohm load and 1W output with four different output taps—the standard 14.22 ohm and 8 ohm taps, and the 3.55 ohm and 0.89 ohm high-current-configured taps. While the 0.89 ohm tap gives the lowest distortion through the midband, it rapidly rises to meet, then exceed the distortion of the other taps at high frequencies. (Though this will not in itself be audible, the distortion harmonics lying above the audio band, it may well result in audible…
Sidebar 2: Specifications
Description: Vacuum-tube stereo amplifier, with transformer-coupled output stage. Power output: 100Wpc (20dBW), both channels driven, 30Hz-15kHz, at less than 2% THD. Frequency response: 4Hz-40kHz, -3dB, at 1W. Sensitivity: 800mV RMS for full power. Input impedance: 100k ohms. S/N ratio: 80dB, DC-1MHz; 100dB, 20Hz-20kHz.
Dimensions: 19" W by 5.25" W by 17.25" D. Weight: 40 lbs.
Serial number of sample tested: 90101.
Price: $4290 (1992); no longer available (2003). Approximate number of dealers: 20. Warranty: two-year limited warranty against defects in…