Description: CD player with 26-function remote control, coaxial and optical digital outputs, dual 18-bit DACs, and 8x-oversampling filter. Frequency response: 5Hz–20kHz ±1.0dB. Dynamic range: 92dB. S/N ratio: 105dB. Channel separation: 90dB. Output impedance: 120 ohms. THD at 1kHz: 0.05%.
Dimensions: 17.25" W by 5.5" H by 13.5" D. Weight: 18.7lb.
Serial number of unit auditioned: S91017778C.
Price: $1200 (1991); no longer available (2020). Approximate number of dealers: 350.
Manufacturer: Luxman Corp., 1-3-1 Shinyokohama, Kouhoku-ku Yokohama-shi…
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Sidebar 1: Specifications
Sidebar 2: Associated Equipment
My listening venue remains, with the exceptions noted below, as described in my review of the Audio Research SP9 Mk.II and Counterpoint SA-3000 preamps (Vol.13 No.11). Both the preamps and the Quicksilver amps that drove the Acoustat Twos have been replaced with the Ensemble B-50 (Tiger) control amplifier plugged into an Ensemble Isotrans isolation transformer.
All system interconnect is Ensemble Supraflux, and speaker cable is Ensemble Hotline. The B-50 sits within arm's reach on an Arcici Superstructure II. All CDs used in listening evaluations…
Sidebar 3: Measurements
The output impedance of the D-105u from its fixed outputs was considerably higher than spec at 1200 ohms, though the variable outputs offered a lower source value of 645 ohms. Long cables should be avoided when the player is used from its fixed outputs, though the lower impedance of the variable outputs is sensible when the player is fed straight to the power amplifier. The maximum output level was 2.11V from either set of outputs, while the output was polarity-correct from both outputs, as shown by the linear-phase impulse response (fig.1). Channel separation was…
This photograph of a classic 1960s HP scope (capable of a sharper and brighter trace than today's equipment) at Ben Duncan Research Labs shows a sinewave emerging from an innovative class of solid-state analog amplifiers, developed with Jerry Mead (founder of much-loved Rauch and Otis amplifier brands, also a record producer and drummer). The residual harmonic is so low—around 0.0001% even while delivering several amperes and tens of volts—that it contains stochastic noise, and fancy equipment isn't needed to see that Voila! we have just the 2nd harmonic. No 3rd, no 4th even. The electronics…
Conventional acoustic and audio knowledge has little enough to say about the sonic effects of harmonics when they're gross (ie, 50% to 0.5% of the fundamental). At lower levels, almost nothing is documented, and extrapolation of the high-level effects would seem presumptuous. I have witnessed experiments in which the effects of introducing at below –95dB a spray of harmonics, including the seventh, ninth, and eleventh, by loading-down an IC op-amp, are: a) perfectly audible, but b) perceived more as a dulling loss of detail and air than as dissonant in the usual sense of "anti-melodic" or…
Sidebar 1: References & Further Reading
+[1] Jim Williams, Analog Circuit Design—Art, Science & Personalities. Butterworth-Heinemann, ISBN 0-7506-9166-2.
[2] Ben Duncan, "Evaluating Audio Op-Amps, Part 1." Studio Sound, July 1990.
[3] Ben Duncan, "Black Box." Hi-Fi News & Record Review, June 2000.
[4] David Bohm, Wholeness and the Implicate Order. Ark Books, 1995, ISBN 0-415-11966-9.
[5] M. Talbot, The Holographic Universe. Grafton Press, 1991; HarperCollins, 1996.
[6] Ben Duncan, "Evaluating Audio Op-Amps, Part 3." Studio Sound,…
Sidebar 2: Integrated Circuits
In 1950, the US Navy's Bureau of Aeronautics needed to build complex, reliable, serviceable weapons systems, but were hampered in this by the tube technology of the time. They thus set up a study of automated tube circuit assembly. The resulting prefabricated circuits were fine, but by the time they were ready, the crucial development of making transistors reliably and cheaply by making them "epitaxially"—ie, by growing doped layers on crystals rather than by hit-or-miss mechanical assembly—made several million dollars' worth of fine tube-based engineering…
Sidebar 3: Hard-Line Objectivists
"Hard-Line Objectivists" is my name for certain self-appointed Czars of audio equipment design. They think that the senses of humans, even skilled audio professionals, should never be relied on in matters of audio equipment assessment using music; that only test gear should decide; that audio equipment is perfect and sounds "blameless," provided it meets highly limited tests; that only a steady sinewave is required to discover all that is knowable about audio equipment; that capacitor, resistor, thermal, and dynamic distortions do not exist because they…
Sidebar 4: Acid Tests for Musically Refined Electronics
My colleagues have noticed over the years that, with refined audio electronics built to be musically satisfying,
The worst room acoustics can be conquered or at least greatly ameliorated.
Music can be played effortlessly at extreme SPLs without ear pain or stress (see my "Earlash" in the June 1995 Studio Sound).
Threshold shift is absent—when a 130dB peak SPL sound stops, birdsong is as audible as if nothing loud had happened.
In people with previously damaged ears, tinnitus is not triggered…
Postscript August 2020
As a band plays a lazy jazz-blues in the corner, and everyone has gotten refreshed with eine kaltes Bier, the professor's central-European audience are warned that a small spectral leakage across multi-channel ICs is developed into a far greater and wider kind of audioland X-contamination, as outlined below.
Another threat is the Ring of 3, an op-amp "state variable" topology used in posh equalizers and crossovers. As with the innards of NFB amplifier stages, while low distortion on the outside lures use, voltage waveforms inside the ring aren't pretty.…