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The audio industry lost another of its veterans on May 23 with the passing of George Bischoff. Over more than four decades, George touched many facets of the industry beginning with Personalized Audio, his retail shop in Dunellen, NJ. He began many creative audio pursuits. He sold over 300 kits that replaced the two tweeters of the Dahlquist DQ 10. With his first speaker he independently discovered the Dynaco A35's aperiodic bass loading. George was an importer for Pink Triangle turntables, Helius tonearms and Beard electronics. He was a partner and co-designer for Melos starting with the…
This is a true story about a surprising 1W integrated amplifier—a push-pull, class-A, output-transformerless tube amp—that drove my DeVore Fidelity Orangutan O/93 speakers to 90dB average levels with grace, spiderweb detail, liquidity, and—unbelievably—a small degree of bass slam.
What the hell is it?
Have you ever observed an object for which you had no name? I mean, no whatchamacallit name at all? In the anthropological story of humans, the act of naming has powerful significance. In our everyday world, humans, objects, and forces don't fully exist for us until they're baptized,…
Later, when I inserted in front of the ZOTL—which I now used as a tubed line stage—PrimaLuna's ProLogue Premium, a 36Wpc tubed amplifier ($2199), the slam pinned my psychic VU meters, but transparency and flow weren't diminished at all. If you're a freak for pace, rhythm, and timing (aren't we all?), the Linear Tube Audio amp can shake, boogie, and run with the best. Oh, yes—and it plays Schubert lieder as sung by Elly Ameling, and Robert Johnson's "Walking Blues" as performed by Paul Butterfield!
The combo of microZOTL2.0, ProLogue Premium, and Soul Supremes played music in a uniquely…
Sidebar 1: Specifications
Description: Tubed, stereo headphone amplifier with separate 12V DC power supply module. Tube complement: two 12AT7 miniature dual-triodes, two 6SN7 octal dual-triodes. Maximum output power: 1Wpc into 4 ohms, 0.5Wpc into 14 ohms. Voltage gain: 10.3dB into 4 ohms, 12.4dB into 14 ohms. Sensitivity: 600mV RMS for full output. Output impedance: 2 ohms. Input impedance: 50k ohms.
Dimensions: 9.4" (241mm) W by 4.7" (120mm) H by 7.7" (197mm) D (amplifier chassis). Weight: 5.5 lbs (2.5kg).
Finishes: Black or Midnight Blue, clear Lexan top.
Serial number of…
"This is getting to be a habit."
That's how I ended the first paragraph of my review of Bowers & Wilkins' 800 Diamond speaker, in the May 2011 issue; apparently, Stereophile's habit of reviewing models from B&W's 800 series remains unbroken.
Later in that review, I said that "The 800 Diamond doesn't look radically different from its predecessors." That doesn't apply to the 802 D3 Diamond ($22,000/pair). It's still a three-way system with tapered-tube high-frequency and midrange enclosures, stacked and nestled into a generous bass enclosure that's vented on the bottom into…
Sidebar 2: Associated Equipment
Analog Source: Linn LP12 turntable, SME M2-9 tonearm, Dynavector DV-20X2L cartridge.
Digital Sources: Schiit Audio Bifrost D/A converter, Integra DPS-7.2 disc player.
Preamplification: Dynavector SUP-200 step-up transformer & P75 Mk.3 phono stage; Parasound Halo JC 3+ phono stage; PrimaLuna ProLogue Premium, Simaudio Moon Neo 350P preamplifiers.
Power Amplifiers: Line Magnetic LM-518IA, PrimaLuna ProLogue Premium, Simaudio Moon Neo 330A.
Integrated Amplifiers: Schiit Audio Ragnarok, Simaudio Moon Neo 340i.
Headphone Amplifiers:…
After connecting the 802 D3s to my Theta Digital Dreadnaught D power amplifier with AudioQuest Oak biwire cables, I fine-tuned the B&Ws' final positions by ear with familiar recordings.
Listening
Although my usual protocol is to do no critical listening for a few weeks, I was able to get down to it very quickly: my sample had been shipped not from B&W's factory but from their design, research, and listening facility in Steyning, West Sussex. For all I know, they're the pair I auditioned when I visited last August).
At Steyning, the first thing I'd noticed about the…
Sidebar 3: Measurements
I performed a full set of measurements on the Linear Tube Audio microZOTL2.0 using my Audio Precision SYS2722 system (see the January 2008 "As We See It"). The three sets of outputs—headphone, RCA jacks, speaker terminals—are connected in parallel, with a shunt 470k ohm resistor connecting the hot connection to ground. I therefore took most of the measurements from the RCA jacks. Because the amplifier's unique output stage uses an RF oscillator modulated with the audio signal, there was around 7mV of RF noise present on its output, so I experimented with using…
Sidebar 1: Specifications
Description: Three-way vented-box loudspeaker. Drive-units: 1" (25mm) diamond-dome tweeter, 6" (150mm) Continuum-cone FST midrange driver, two 8" (200mm) Aerofoil-cone woofers. Crossover frequencies: 350Hz, 4kHz. Frequency range: 14Hz–35kHz. Frequency response on reference axis: 17Hz–28kHz, ±3dB. Sensitivity: 90dB/2.83V/m. Harmonic distortion (second and third harmonics, 90dB, 1m): <1%, 80Hz–20kHz; <0.3%, 100Hz–20kHz. Impedance: 8 ohms nominal, 3.0 ohms minimum. Recommended amplification: 50–500W into 8 ohms on unclipped program. Maximum recommended cable…
Sidebar 2: Associated Equipment
Digital Sources: Oppo Digital BDP-105 universal BD player; Baetis XR2 PC-based music server; exaSound e28, Merging Technologies NADAC-8 multichannel D/A processors; QNAP TS569L NAS.
Preamplifiers: Audio Research MP1, Parasound Halo P 7.
Power Amplifiers: McIntosh Laboratories MC303, Parasound Halo A 31, Theta Digital Dreadnaught D.
Loudspeakers: Bowers & Wilkins 800 Diamond.
Cables: Digital: AudioQuest Vodka (HDMI) & Carbon (USB). Analog Interconnects: AudioQuest Earth/DBS balanced, Kubala-Sosna Anticipation (RCA, XLR). Speaker:…