Sidebar 5: HDCD Overview
In case you missed my earlier reports, High Definition Compatible Digital is a sophisticated digital encoding and decoding process that preserves more musical information while remaining compatible with the CD's 44.1kHz, 16-bit storage limitation.
HDCD works on two levels: by preventing distortion that occurs during conventional coding, and by squeezing more information into the 44.1kHz, 16-bit data channel. The HDCD process starts by digitizing the analog input signal with a high sampling rate and a long word length (probably at least 88.2kHz and 20-bit…
Sidebar 6: The PMD100 HDCD Decoder
The PMD100 HDCD decoder chip not only decodes HDCD-encoded sources, but also has within it an 8x-oversampling digital filter. The filter, which is integral to the HDCD process, is used whether or not the source signal has been HDCD-encoded. Consequently, the PMD100 replaces the NPC filter used in most other processors.
The filter section within the PMD100 was designed with a number of design criteria that were derived from Pacific Microsonics' psychoacoustic research—criteria reportedly not applied to existing digital filters. Pacific…
Sidebar 7: JA on HDCD
The obvious comparison for a new technology such as HDCD is to audition the same recording in HDCD and non-HDCD formats through the same D/A processor, so that you can isolate the effect on sound quality due to the HDCD process alone. But this is hard to do. You can audition an HDCD disc through the SFD-2 Mk.II processor, which will give you the full HDCD sound quality, but you can't play the HDCD disc through the SFD-2 Mk.II with the HDCD decoding disabled. You can play the HDCD disc through a non-HDCD D/A, but then the inherent sonic differences between that…
Sidebar 8: Mk.II Measurements
The SFD-2 Mk.II's maximum output level was 3.15V from the balanced outputs, 1.57V from the unbalanced outputs—rather low levels. In fact, the Mk.II has about half the output voltage of the original SFD-2. This is no doubt due to the 6dB of gain-reduction required by the HDCD license when playing non-encoded signals (see "The PMD100 HDCD Decoder" Sidebar).
Output impedance measured at the balanced jacks was 365 ohms at 1kHz and above, increasing to 1350 ohms at 20Hz. Although these are moderately high values, the Mk.II's output impedance is…
Sidebar 9: Specifications
Description: Digital/Analog Converter with vacuum-tube output stage. Filtering: 8x-oversampling, HDCD. Conversion: differential 20-bit UltraAnalog DACs. Output stage: Fully balanced vacuum-tube. Tube complement: two Sovtek 6922 dual triodes (6DJ8). Digital inputs: coaxial on RCA jack, AES/EBU on XLR jack, and ST-type optical. Digital outputs: one S/PDIF on RCA jack. Analog outputs: one pair single-ended on RCA jacks, one pair balanced on XLR jacks. Frequency response: 5Hz-20kHz ±0.5dB. S/N ratio: >110dB ("A" weighted). Channel separation: >105dB at 1kHz,…
Back in 1968, nothing sounded better to me than "Penny Lane"—one of my all-time favorite songs—blasting out over my Dad's home-built Eico gear (when no one else was around, of course). For some reason, the various sounds packed into that song grabbed my attention as much as that old integrated amp whose steel case got as hot as the tubes inside—ouch! When the Beatles broke up, I played Magical Mystery Tour over and over for days before I felt I'd paid them sufficient homage. Like everyone else, I heard a lot of the Beatles through the '70s and '80s. (And now, of course, it may as well be the…
High-end audio is like religion: Now and again you've got to question your principles, if only to keep dogmatism and blind faith at bay. (As the famous theologian Paul Tillich put it, you've got to have faith and doubt.) Well, my trip down Penny Lane made me feel like the fifth Beatle—Doubting Thomas. You do have to wonder: If you can enjoy music so much with a car radio or a table-top special, why spend thousands on some high-resolution equipment that will just break the bank and distract you with details the musicians and producers were trying to hide in the first place? And what…
From London, England, to Santa Fe, New Mexico, is a pretty big jump, both geographically and culturally. From Hi-Fi News & Record Review to Stereophile, however, is a mere hop; the similarities overwhelm the differences. Unlike the US, mainstream magazines in the UK have managed to keep in touch with the fact that hi-fi components sound different; to edit and to write for an ostensibly "underground" American magazine presented no major philosophical problems. (I say "to edit," but as mentioned in "The Big Announcement," Vol.9 No.3, my editing is done in harness with Stereophile's founder…
Leaving aside for a moment the fact that the Wavac SH-833 costs $350,000/pair—
Okay, you can't leave it aside. Neither can I. They cost $350,000, fer chrissakes! Can any pair of amplifiers possibly be worth that? What's inside those boxes that could possibly make them cost $350,000? Will anyone actually pay $350,000 for a pair of 150W amplifiers?
Yes, $350,000 is a great deal of money to pay for a pair of amplifiers. In fact, it's a great deal of money to pay for a luxury car: you could buy an Aston-Martin Vanquish and pocket around 100 grand. It's a fair price for a…
Accidents
Despite having been carefully packed in substantial wooden crates, the SH-833 arrived damaged, including a bent isolation-transformer chassis, which is constructed not from sheet metal but from solid metal plates that range in thickness from 10mm to 50mm. There was more damage in one of the main amplifiers. It took the designer the better part of a day to undo the pallet punter's work. (I didn't get special treatment: a visit from a Wavac rep., most likely Yuzuro Ito or Yasunori Matsuki, is part of what your $350,000 buys you.) A week or so into the review, one channel failed…
