Intrigued by Dick's description of the Lazarus preamp's phono stage as having "zippy" treble transients, I ran a low-level 1kHz squarewave through the magazine's inverse RIAA network into the Cascade Deluxe's phono input (set to 47k ohms impedance). Fig.1 shows the result at the tape output sockets: excessive leading-edge overshoot which will certainly lend an "etched" quality to the sound in the treble, as well as exaggerate the audibility of disc surface noise. Note also the slight uptilt to the plateau of the waveform, implying too much upper-bass energy. The…
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Parts quality is very high. The capacitors associated with the Bitstream DAC are primarily polystyrene, all resistors are 1% metal-film types, and four of the resistors in the feedback loop are $3 non-inductive wirewound types. These resistors reportedly had a huge effect on the Prime's sound quality. In addition, a few Teflon capacitors (very expensive) are used in critical audio stages. The metal work is zinc over copper over steel, and the pcb is glass epoxy.
Overall, the Prime is an engineering marvel for its modest price. There is far more inside the unit than one would expect for…
Sidebar 3: Specifications
Description: Tube preamplifier with hybrid solid-state/tube phono design. Frequency response: 20Hz–20kHz, +0/–1dB. High-level sensitivity: 100mV in for 1V out. Phono sensitivity: 0.2mV for 0.5V output at 1kHz. Phono overload: 50mV (no frequency specified). Phono input impedance: adjustable from 26 ohms to 47k ohms in 8 steps, in parallel with 25pF. Line input impedance: 100k ohms. Measured output impedance: 1030 ohms.
Dimensions: 19" W by 10" D by 2" H.
Serial number of sample tested: 2062.
Price: $1199 (1989); no longer available (2015). Approximate…
Sidebar 1: Review System
The Prime took center stage in my digital front end for the past two and a half months. It was driven primarily by Theta's Data CD transport through Theta's own digital interconnect. The preamplifier was either the extraordinary Audio Research LS2 reviewed last month or the EVS Stepped Attenuator, a passive level control.
Loudspeakers were the Hales System Two Signatures augmented by the Muse Model 18 subwoofer, driven by VTL 225W Deluxe Monoblocks. Interconnects were the AudioQuest Diamond and Lapis or Straight Wire Maestro, and speaker cable was bi-…
Sidebar 2: Measurements
This is the first set of measurements using Stereophile's Audio Precision System One with the new "Dual Domain" upgrade. Unlike a standard System One, the Dual Domain can generate and analyze signals in the digital domain. Previously, digital signals for testing D/A converters were read from suitable test discs and taken from the digital output of a CD player. With the Dual Domain, we can generate a variety of chosen signals rather than being stuck with only the signals of test CDs. In addition, the Dual Domain has waveform capture (with 16-bit resolution) and FFT…
Sidebar 3: Specifications
Description: 4x-oversampling software-based D/A processor with Bitstream DAC. Digital filter: 4x-oversampling Theta composite filter using one Motorola 56001 DSP chip. D/A conversion: 64x-oversampling Philips Bitstream DAC. Frequency response: DC–20kHz +0dB, –0.4dB. THD+N –104dB at 1kHz referenced to full scale. Output impedance: 50 ohms.
Dimensions: 19" W by 2.5" H by 10.5" D. Weight: 14 lbs net, 16 lbs shipping.
Price: $1250 (1991); no longer available (2015). Approximate number of dealers: 90.
Manufacturer: Theta Digital, Agoura Hills, CA 91301 (…
Manufacturers' Comment
Editor: It is, of course, disappointing to receive an unfavorable review. A product designed and voiced at this level is inherently an opinion carefully stated. Michael's review is as well, and we differ. As Michael says, "that's hi-fi." We strive for fast transient ability and very low distortion. These are the qualities that we feel bring the ability to "hear the room," the 3D character of the recording space, the soundstage that removes the speakers' locations from the listener's perception. For us, this is the challenge. It is how we design and voice our systems…
During my reviews of digital processors in the past year or so, I've made comparisons with the Wadia 2000 Digital Decoding Computer first reviewed by Arnis Balgalvis in Vol.13 No.1. I've felt that, as good as the 2000 is, other processors—many costing less than the 2000's $8500 price tag—are now superior.
However, a visiting Wadia representative looked inside our sample and used the word "ancient" to describe its circuitry in relation to current production. In addition, I was never able to audition the 2000 with a glass fiber-optical interface, standard equipment on Wadia's transports.…
Follow-Up from October 1992 (Vol.14 No.10):
In my report on the Wadia Digimaster 2000 in the June issue, I reported on the latest version of this sophisticated processor's sonic and technical attributes. I found the 2000's musical presentation extraordinary—unequivocally Class A performance in Stereophile's "Recommended Components." My measurements, however, revealed some odd behavior: the low-level linearity was very poor—among the worst I'd ever measured—and the unit decoded a –90dB, 1kHz signal at –100dB and generated a spurious 2kHz signal nearly equal in amplitude to the test…
Follow-Up from December 1996 (Vol.19 No.12):
Wadia Digital has offered four upgrades of its 2000 Digital Decoding Computer since the model's 1989 debut. The first was a streamlined power supply that was much more aesthetically pleasing than the square metal box supplied with the first units. Multiple digital inputs on the 2000 also replaced the separate fiber-optical converter and its outboard power supply—necessary if you wanted to decode more than one digital source—and reduced the four-box 2000 to two.
The latest upgrade is much more extensive: the 2000's entire circuitry is…