Even hedging RC with every warning we can, many people look only to it for buying advice. The commercial importance of "Recommended Components" has gotten so…
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Though it's Stereophile's most popular single feature, "Recommended Components" has many problems. The biggest is that you readers use it—but then, if I didn't want that, why would we publish it? More accurately, problems come from uncritical use, as if only products that "make" "Recommended Components" are worth buying. Alternatively, it's concluded that products which drop out have somehow been consigned to an outer darkness.
No, the $399 price listed in the specification block isn't a misprint. And yes, the Audio Alchemy Digital Decoding Engine v1.0 is indeed a full-function outboard digital processor. And since this is the August issue, not April, you can stop worrying that this review is some kind of joke.
The $399 Digital Decoding Engine is for real.
But how can Audio Alchemy make an outboard D/A converter for about half the price of the next most inexpensive decoders (the PS Audio DigiLink and Melior Bitstream D/A)? Can it be any good? These were my first reactions to the DDE, and I'm sure many…
Sidebar: Review System
I auditioned the Audio Alchemy DDE with my usual reference system: Hales System Two Signatures driven by VTL 225W Deluxe monoblock tube amplifiers, and Muse Model 18 active subwoofer. The preamp was either an Audio Research SP11 Mk.2 or the passive Electronic Visionary Systems Stepped Attenuator.
3' runs of bi-wired AudioQuest Clear/Dragon connected the VTLs to the Hales, and interconnect was AudioQuest Lapis and Diamond. Other processors on hand for comparison included the Meridian 203 ($990) and PS Audio SuperLink ($1195, footnote 1). Both these…
Sam Tellig wrote about the Digital Decoding Engine in October 1992 (VOl.14 No.10):
Would you believe $399 for a digital processor?
Now this is my kind of product. I'm a real cheapskate when it comes to anything digital, because the technology changes so fast. Think about it: your new $3000 processor will likely be superseded in six months or so by a Mk.II or III version; if you only paid $399 for your Alchemy, you won't be too worried when v2.0 comes out. If you do want to spend big bucks on hi-fi, do something sensible like buy a pair of Quicksilver Silver mono amps, or a Jadis…
Sidebar 2: Measurements
The Digital Decoding Engine performed quite well on the bench. It didn't measure as well as some more expensive units, but nothing in the measurements would indicate its budget heritage.
Driving the DDE with data representing a positive-going impulse revealed it to be non-inverting with the front-panel switch in the 0° position, and inverting in the 180° position. No DC was measured at the output jacks, but there was a very low level (2mV p–p) of high-frequency noise (350kHz) always present at the output. Output impedance was 220 ohms across the band, not…
Sidebar 3: Specifications
Description: Single-box D/A provessor. Conversion: Bitstream, PDM—256x resampled. Data input sampling range: 40kHz–50kHz. Digital filter: 4x. Analog post filter: 3rd-order at 60kHz. Noise shaping: second-order. Inputs: coaxial on an RCA jack, optical on a Toslink jack. Outputs: RCA jacks, 2.75V output level at full scale. Three front-panel indicators: analog/digital power, incoming data lock. Frequency response: 20Hz–20kHz ±0.2dB. Resolution: 16 bits. THD+noise: –90dB. S/N ratio: greater than 93dB. Channel separation: 80dB (no frequency specified). Linearity: ±…
Four years after its launch, the CD medium would appear to have come of age, at least in production terms. Annual player manufacture is now big business, and there is hardly a major audio brand without a CD machine to its name—even such analog stalwarts as Audio-Technica and Shure have succumbed.
A huge range of models is apparently available—"apparently" because many machines are repackaged versions of a few basic designs. Prime originators include Yamaha, Philips, Nagaoka, Toshiba, Kyocera, Denon, Hitachi, and Sony, these serving certain specific model requirements as determined by…
Sidebar 1: Test Program
The Cambridge CD player was subjected to a formal sequence of tests. In the lab, a range of tests was applied to explore the linearity and resolution of the machine. Factors such as shock and vibration immunity, error correction, and the like were all investigated. If A/B assessment is to be attempted, it is vital to determine absolute output levels, and it is well worth checking any deviations in frequency response which might affect the auditioning.
The precise bit resolution delivered is at present academic, as we have not yet been able to…
Sidebar 2: Measurements
On the filter 1 setting (fig.1), the response was essentially flat, measuring –0.2dB at 20kHz. On 2, the response fell away beyond 3kHz to –2dB, 20kHz. With filter 3, the output shelved just a little, this being the designer's preferred characteristic. On 4 (1 and 3 depressed), the bass rolled off early by 2dB into our low-impedance chart-recorder loading, while the high treble was slightly depressed—anti-fuzz, perhaps? On 5, the treble rolloff accelerated, while 6—all filter buttons depressed—gave a maximum level of cut at both extremes.
Fig…
Sidebar 3: Specifications
Description: Two-box, solid-state CD player.
Price: $2800 (1987); no longer available (2104).
Manufacturer: Cambridge Audio, England. US Distributor: Sumiko, Inc., Berkeley, CA 94705 (1987); Audio Plus Services, 156 Lawrence Paquette Industrial Drive, Champlain, NY 12919 (2014). Tel: (800) 663-9352. Web: www.cambridgeaudio.com.