I examined the PS Audio PerfectWave DirectStream's electrical performance with my Audio Precision SYS2722 system (see www.ap.com and the January 2008 "As We See It"). To test its USB input, I used my 2012 MacBook Pro running on battery power. Unless stated otherwise, all measurements were performed from the processor's balanced outputs. I don't yet have files of DSD-encoded test signals, so I assessed the DirectStream's measured performance with PCM-encoded files, with sample rates extending from 44.1 up to 352.8kHz. All testing was done with the DirectStream…
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The French do things differently. I first heard Triangle loudspeakers at the 1981 Festival du Son, in Paris. That was, of course, after I had obtained admission to the show, in a nonintuitive process in which members of the press obtained their credentials at a booth inside the show. But my experience of the Triangle speaker, a small, three-way floorstander, was positive: It sounded clean and uncolored, and nothing like the BBC-inspired speakers I preferred at that time. The Triangle wasn't as neutral as the English norm, but there was something appealing about its sound—something that, I…
I have mentioned before how much I appreciate Bruce Hornsby's practice of making his live concerts available for download. As I write these words, I'm listening to Bruce Hornsby & the Noisemakers' live 2009 recording of "Road Not Taken," from Dagle's Choice Vol.4 (16/44.1 ALAC transcoded from FLAC download). The Noisemakers, a superbly tight band, feature Captain Beefheart alum J.T. Thomas on keyboards, as well as bassist J.V. Collier, whose phat lines on five-string bass guitar in this track sounded propulsive through the Triangles. But the weight of the lows didn't obscure or…
Sidebar 1: Specifications
Description: Three-way, four-driver, floorstanding loudspeaker with vented enclosure. Drive-units: 1" (25.4mm) horn-loaded, titanium-dome tweeter; 7.3" (185mm) paper-cone midrange unit; two 7.3" (185mm) fiberglass-cone woofers. Crossover frequencies: 280Hz, 2.7kHz. Frequency response: 35Hz–20kHz, ±3dB. Sensitivity: 92dB/2.83V/m. Impedance: 8 ohms nominal, 3.2 ohms minimum. Power handling: 120W continuous, 240W repetitive peak power.
Dimensions: 48.4" (1230mm) H (with plinth) by 9.2" (233mm) W (with plinth, 14.6" (370mm)) by 14.7" (372mm) D. Weight: 72.6 lbs…
Sidebar 2: Associated Equipment
Analog Sources: Linn Sondek LP12 turntable with Lingo power supply, Linn Ekos tonearm, Linn Arkiv B cartridge.
Digital Sources: Ayre Acoustics C-5xeMP universal player; Apple 2.7GHz i7 Mac mini running OS10.9.3, iTunes 11, Pure Music 1.89 & 2.0, Audirvana Plus 1.5.10; Logitech Transporter media server; Auralic Vega, Luxman DA-06, PS Audio PerfectWave DirectStream D/A processors; dCS Vivaldi upsampling D/A system; Ayre Acoustics QA-9 USB A/D converter.
Preamplification: Channel D Seta L phono preamplifier; Pass Labs XP-30, Ayre Acoustics KX-R20…
Sidebar 3: Measurements
I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the Triangle Signature Delta's frequency response in the farfield, and an Earthworks QTC-40 for the nearfield and spatially averaged room responses. My estimate of the Signature Delta's voltage sensitivity was 91.8dB(B)/2.83V/m, which is both much higher than average and basically agrees with the manufacturer's specification of 92dB. The Triangle's electrical impedance and electrical phase angle are shown in fig.1 (solid and dashed traces, respectively). The Delta is a much kinder load…
Martin Colloms reviewed the Tempest in April 1987 (Vol.10 No.3)
The original Tempest, produced through the end of 1986, was reviewed by John Atkinson in Vol.9 No.6. As a result of using Mike Moffat as a consultant, however, CAL introduced some changes in early 1987, mainly relating to improvements to waveshapes and to power-supply noise levels in the digital sections. The new Tempest is not designated differently from the original, and costs $2095. An upgrade from original to current can be had for the difference in their prices ($200). CAL has also introduced a less-expensive, 16-bit…
Sidebar: Measurements
The bulk of the test data relates to the original Tempest. As regards frequency response (fig.1), this deck was less flat than most; not only does it have the usual Philips 14-bit system HF ripple, which imparts a subtle but identifiable sonic signature, it also showed a hint of treble lift (+0.2dB) by 20kHz, coupled with a 1dB droop in output by 20Hz (into the 11k chart recorder load) due to the finite size of its output capacitors. In consequence, input impedances in the 50k–100k ohm range are recommended to help maintain good bass extension. 100k loading…
Robert Harley returned to the VTL 225W Deluxe in October 1991 (Vol.14 No.10):
When I reviewed the VTL 225W Deluxe Monoblocks in January 1990, I concluded that they were the most musically satisfying amplifiers I had ever heard. Despite the intervening years and products, the 225s still do it for me. They have an unparalleled midrange liquidity, harmonic rightness, and a detailed yet unfatiguing presentation. After reviewing other amplifiers—many superb in their own rights—it is always a joy to return to the special qualities that make the 225s so musically compelling.
With the…
Sidebar: Measurements with EL34s
I'll begin the measurements with the EL34'd 225s, and save any comparisons with the KT90 version for the KT90 measurements section.
The EL34'd 225's output impedance was just under an ohm across the band, measuring 0.97 ohms at 20Hz, 0.89 ohms at 1kHz, and 0.79 ohms at 20kHz. This is a moderate value for a tube amplifier, but high in relation to most solid-state amplifiers. For comparison, the VTL Compact 160 reviewed in August had a very high output impedance of about 1.5 ohms at 1kHz in triode mode and 2.2 ohms in pentode mode. The 225's high…