Digital sources: PS Audio Lambda II transport, Bel Canto DAC 1 and MSB Link III (with upsampler board, Full Nelson option, P1000 power supply) digital processors.Preamplifier: Convergent Audio Technology SL-1 Ultimate.Power amplifier: Cary CAD-2A3-SE monoblocks.Loudspeakers: Avantgarde Acoustic Uno Series Two.Cables: Digital: Illuminati Orchid, Kimber Illuminations D-60. Interconnects: Nordost Quattro Fil. Speaker: Nordost S.P.M. Reference. AC: TARA Labs Decade.Accessories: Argent RoomLenses (4) room treatment, PS Audio P-300 AC synthesizer with MultiWave…
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Sidebar 3: Associated Equipment
Sidebar 4: Measurements
For these measurements, the P-1A and P-3A were both powered from the Monolithic Sound P3 supply. The P-3A's D/A converter didn't invert absolute polarity with its front-panel LED illuminated green, but did do so when the LED was red. It had a maximum output of 2.373V RMS, just under 1.5dB higher than the CD standard of 2V, with an output impedance below 1 ohm across the audioband. Channel separation (not shown) was superb, at better than 120dB below 400Hz, but with capacitive coupling between the channels reducing this to a still excellent 87dB at 20kHz.
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Harmonic distortion (fig.7) was very low, the third harmonic being the highest in level at -91dB (0.003%), even into 600 ohms. The only other harmonic to poke its head above the -100dB level was the seventh. Intermodulation distortion was also very low (fig.8), the 1kHz difference component lying just above -100dB (0.001%). However, note the spectral spreading of the primary 19kHz and 20kHz tones, which may be due to the Crystal sample-rate-converter chip running out of mathematical headroom with this demanding signal. (I originally suspected wordclock jitter as the culprit, but the P-3A has…
I relocated the beautiful little P-3A to my listening room, returned to the lab, and looked at what the P-1A was doing in the digital domain. I used the generator board of a dual-board PrismSound DScope II to synthesize a dithered 16-bit 1033Hz sinewave at 0dBFS, and used the analysis board to perform a high-resolution (32,768 points) FFT-derived spectrum of the P-1A's AES/EBU data output. (I averaged 64 spectra to reduce the contribution of random noise.) The blue trace in fig.12 shows the spectrum of the data output by the DScope: the 1033Hz FFT bin in this 1Hz-resolution graph hits the…
Sidebar 5: Manufacturer's Comments
Editor: On behalf of everyone at Perpetual Technologies, I'd like to thank Stereophile and Bob Deutsch for this incisive and positively well-done review. We realize that the P-1A (particularly) and the P-3A present several reviewing challenges, and we really feel that the products were well understood and reviewed. Of course, this is only the opening act, as it were. My comments will be mostly nontechnical in nature, but directly after my few words from the grandstand, Peter Madnick and Keith Allsop will weigh in with some important technical comments…
Robert Deutsch wrote a Followup on the ModWright P-3A modification in October 2001 (Vol.24 No.10):
Perpetual Technologies' P-3A digital processor offers astonishingly good performance, surpassing some highly regarded products that cost significantly more than its $799 price. (See my review in the January 2001 issue.) However, the fact that the P-3A is built to sell at a relatively modest price means that component quality cannot be the best. With this sort of product, the question that occurs to audiophiles who are into DIY (Do It Yourself) is whether the sound of the unit could be…
I have always had a soft spot in my heart for Jeff Rowland's products. Going back to the Model 7 monoblock power amplifier and the Model 5 stereo amplifier of nearly 20 years ago, Rowland's designs always sounded essentially musical to me, and quite forgiving and non-fatiguing.
At a time when other designers of high-end solid-state equipment seemed to be pushing the envelope in terms of definition and detail—which, in some setups, was often at the cost of grayness or graininess (or at least fatigue)—Rowland's amps were usually a congenial refuge. Especially in the context of certain…
Sidebar 2: Specifications
Lyra Parnassus D.C.t: Low-output moving-coil cartridge with Ceralloy diamond-coated cantilever, low-mass, Ogura PA line-contact stylus, six-nines single-wind copper coils, five-nines iron core, and body milled from a single piece of titanium. Source impedance: 2 ohms. Recommended stylus pressure: 1.6–1.8gm. Compliance: Approximately 12cu (compliance units) at 100Hz. Channel separation: 35dB or better at 1kHz. Frequency range: 10Hz–50kHz. Output: JVC TRS-1007 standard, 250µV (3.54cm/s, 45° peak); CBS STR-100 standard, 350µV (5cm/s). Recommended load: 50–47k ohms…
If anyone ever thinks to compile a list of the 100 seminal audio papers that should be found in every tech-aware audiophile's filing cabinet, Harry Olson's "Direct Radiator Loudspeaker Enclosures" deserves to feature in it. Originally presented at the second Audio Engineering Society Convention, in October 1950, it was published in Audio Engineering in 1951. In 1969—in a rare and certain acknowledgement of its classic status—the AES republished it in its Journal (footnote 1).
Olson's paper was all about the shapes of loudspeaker cabinets and the influence they have on frequency response…
According to the simplified view of fig.1, we should expect to see edge reflections occurring between about 200 and 700 microseconds (µs) after the direct sound, with peaks in the reflected energy at 300µs and 650µs. An important point to note about this time scale is that these delays are all less than 1 millisecond (1ms), although they would obviously increase with larger baffle dimensions. (When path-length differences between the baffle edges and listening position are added in, the time delays increase slightly, but not by much. For instance, at a listening distance of 3m or 10', edge…