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Despite the myriads of technological breakthroughs announced month after month with tedious regularity by manufacturers of pickups, amplifiers and loudspeakers, there are only five developments in the 101-year history of audio reproduction (footnote 1) that we would call truly revolutionary. We will doubtless offend many by stating that Edison's phonograph was not one of them. It was the starting point, it was not a turning point. Emile Berliner's disc was revolutionary, in that it changed the whole format of sound reproduction, and made possible true mass production of recordings (footnote…
Sidebar: Pulse Code Modulation
Digital PCM (Pulse-Code-Modulation) encodina converts the continuous energy fluctuations of the conventional (analog) audio signal into a series of pulses which are either completely On or completely Off. All of the analog information is retained as variations in either the duration or the repetition rate of the pulses. Thus, all subsequent amplification can be done by devices acting as switches, which are either On or Off. Signal degradation can occur only as a result of imperfections in the circuits which do the PCM encoding and subsequently, the decoding…
As a film title, Quantizing Hanson Hsu might not rank up there with Kissing Jessica Stein, but we work with what we have to work with. Hanson Hsu is the principal designer at Delta H Design, Inc., an acoustics and architecture firm based in Marina del Rey, California. Though he dabbles in some weird science, Hsu doesn't wear a white lab coat, literal or figurative. He's down-to-earth and personable, with a conversational style that evinces warm wit and a real love of music. At one point in our conversations, he exclaimed, "I get so much joy when things sound good."
Hsu's background…
I presented to Hsu a hypothetical case: a 19' by 13' post-and-beam room with 10'-high sidewalls and a peaked ceiling, housing a pair of Sonus Faber Amati Futura speakers driven by Audio Research electronics. Short of the 50% coverage target, Hsu believes that the Pareto-optimal (my phrase) ZR Technology installation for an ambitious home listening room of this size would cost between $15,000 and $25,000. However, he also said that the "ultimate experience" would require spending $50,000 or more. What spending more gets you is even more of the music as it was recorded, with fewer of the…
I was weak and easily led.
In 1978, after enduring four or five years of wretched music made by men with long hair and beards and tendencies toward eonic guitar solos, I suddenly discovered that the only music worth hearing was made by clean-shaven men of limited musical proficiency. I embraced the Clash, the Pistols, the New York Dolls, the Ramones, and the Buzzcocks. I cut my hair and gave away some of my old records. I even threw out my copy of Jethro Tull's A Passion Play—which, now that I think about it, wasn't that bad an idea.
Then I woke up and remembered: I'd left the…
Sidebar: Contacts
DHDI/Delta H Design Inc., 13900 Marquesas Way #6005, Marina del Rey, CA 90292. Tel: (310) 581-2331. Web: www.deltahdesign.com
Tellurium Q Ltd., The Willows, Bonds Pool, Langport, Somerset TA10 9QJ, England, UK. Tel: (44) (0)1458-251-997. Web: www.telluriumq.com. US distributor: Fidelis High-End Home Audio & Theater, 460 Amherst Street (Route 101A), Nashua, NH 03063. Tel: (603) 880-4434. Fax: (603) 880-4433. Web: www.fidelisav.com
A note about gain: According to Reinhard Thöress, the input sensitivity of his 300B amp is intentionally low, to prevent excessive preamp noise in systems that include the high-efficiency speakers with which most Thöress amps will surely be used. The amp's low input sensitivity has the additional benefit of allowing the user to operate his or her preamplifier volume control within a moderate to high portion of its range, where channel tracking is optimal—and that certainly proved true in my system.
Listening
The first thing that impressed me about the sound of the Thöress 300B was its…
Sidebar 1: Specifications
Description: Monophonic single-ended-triode tubed power amplifier. Tube complement: one 300B, two EL803S. Input: 1 line-level. Maximum output power: 8Wpc into 16 ohms (12dBW ref. 1W into 8 ohms). Input impedance: 100k ohms. Input sensitivity: 3.25V RMS. Output impedance: transformer matched to 4, 8, 16 ohms (see text).
Dimensions: 13.4" (343mm) H (including tubes) by 5.9" (152.5mm) W by 23.3" (597mm) D (including output terminals). Weight: 28 lbs (12.7kg).
Serial numbers of units reviewed: None found.
Price: $12,995/pair. Approximate number of…
Sidebar 2: Associated Equipment
Analog Sources: Garrard 301 turntable; EMT 997, Thomas Schick tonearms; Ortofon SPU-A & SPU 95th Anniversary & CG25i, Miyajima Premium BE Mono II, EMT OFD 15 & TSD 15 pickup heads.
Digital Sources: Halide Designs DAC HD USB D/A converter; Apple iMac G5 computer running Audirvana Plus v.1.5.12; Sony SCD-777ES SACD/CD player.
Preamplification: Hommage T2 step-up transformer, Shindo Masseto preamplifier.
Power Amplifiers: Shindo Corton-Charlemagne (monoblocks) & Haut-Brion.
Loudspeakers: Altec Valencia, DeVore Fidelity…
Sidebar 3: Measurements
I performed full sets of measurements on both samples of this retro-styled amplifier, using Audio Precision's SYS2722 system (see www.ap.com and the January 2008 "As We See It"). As instructed in the manual, after inserting the tubes and running each amplifier for a while to make sure everything was at the optimal operating temperature, and with no signal applied, I rotated the rear-panel knob of each monoblock to minimize measured hum in the output. This was a straightforward operation and, as you can see from the signal/noise measurements later in this report,…