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I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the JBL Stage A170's frequency response in the farfield, and an Earthworks QTC-40 mike for the nearfield responses. I left off the loudspeaker's grille for the measurements.

JBL specifies the A170's sensitivity as 89dB/2.83V/m, which is both higher than average and confirmed by my measurements. Props to JBL for an honest sensitivity specification. The impedance is specified as 6 ohms; while the solid trace in fig.1 shows that the impedance does drop below 6 ohms in the lower…

I realize that products such as the darTZeel NHB-468 ($170,000/pair) are for the very few, but the very few include far more people throughout the world than you may realize— people who can afford such costly audio products…

With the NHB-468s swapped in, cold out of the box, I listened again. Big sonic change! All for the better, building on…

Description: Solid-state monoblock power amplifier. Inputs: one unbalanced (RCA); one unbalanced Zeel (BNC); one balanced (XLR). Output power: 475W (26.8dBW, 550W peak) into 8 ohms, 625W (25.0dBW, 700W peak) into 4 ohms, 222W into 2 ohms (17.45dBW, 300W peak)—"design limited because CP2C power is delivered differently into speakers than when statically measured." Voltage gain (user selectable): 26 or 32dB into 8 ohms. Input impedance: >30k ohms, (RCA); 50 ohms, ±1 ohm (Zeel); 10k ohms per phase (XLR). Output impedance: <0.28 ohm, 20Hz–20kHz (into 8 ohms).…

Analog sources: Continuum Audio Labs Caliburn, & Castellon turntable & stand; SAT CF1-09 and Kuzma 4Point tonearms ; SME Synergy turntable, Lyra Atlas, Atlas SL, Atlas SL mono, Etna, and Etna SL, Ortofon MC Century, Anna Diamond, A95, Miyajima Labs Infinity (mono) and Destiny (stereo) Grado Epoch (mono).
Digital sources: dCS Vivaldi One SACD player DAC; Lynx Hilo A/D-D/A converter, Roon Nucleus; Pure Vinyl and Vinyl Studio software.
Preamplification: darTZeel NHB-18S, Ypsilon MC-10L, MC-16L, Consolidated Audio SUTs step-up transformers;…

Because of the darTZeel NHB-468's bulk and weight, and also because the amplifiers needed to be picked up for photography as soon as Michael Fremer had finished his auditioning, I drove my Audio Precision SYS2722 system—see the January 2008 "As We See It"—its host computer, my digital and analog oscilloscopes, cables, and all the rest of my test gear to his New Jersey home to perform the measurements.

Prior to trekking to Mikey's, I had received several emails from designer Hervé Delétraz about the new circuit topology he had incorporated in ?the NHB-468,…

Among Toronto's abiding successes, an audio show hasn't been one of them. While the city hosted the annual TAVES, established in 2011 as primarily an audio show, the event's attempt to transform itself over the…

The source consisted of the Roksan 20 Plus turntable ($CAD5300) with Sara unipivot tonearm ($CAD3600) and Shiraz cartridge ($CAD5300). Roksan's Caspian VSC S2 speed control/phono stage completed the package. Though lacking in ultimate scale and bloom, the sound of the system was…

Was I in a hotel room? Couldn't tell, because the sound coming from a pair of Grandinote Mach 9 speakers with carbon fiber enclosures ($CAD50,000/pair), a Grandinote 37Wpc Shinai integrated amp ($CAD20,000), and a Grandinote Volta music server ($CAD14,000), with cabling by Nordost, completely obliterated the walls around me. I was somewhere else. But I think what surprised me most about…