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Conrad-Johnson Premier 7A preamplifier Measurements

Sidebar 2: Measurements

Before I began measuring, I noted that the mute switch on the Premier 7A's left channel was defective. It would stick in one position. Pulling it out manually would release it, but it would then simply stick at the next engagement. Fortunately it stuck in the non-mute position.

The gain of the Premier 7A's line stage—from input to main output—measured 29.6dB in the left channel. The right-channel gain was 0.2dB lower. The line input impedance depended to a small degree on the channel and the setting of the volume control, but ranged from just over 18k ohms…

Music in the Round #25

I've been reading and sometimes participating in a number of Internet discussions that begin with something like "Is SACD (and/or DVD-Audio) Dead?" Regardless of your one-word answer, it seems that the issue is still quite lively. I won't address the question here (you know where I stand), but it almost doesn't matter. Many high-resolution multichannel recordings are still being made. It's just that they may be distributed in different ways.

I asked Robert von Bahr of BIS Records about the fiscal viability of making SACDs. I wondered if the small numbers of sales to audiophiles might be…

Music in the Round #25 Page 2

A case in point is Cary Audio Design's Cinema 11 surround processor ($3000). Last fall, when I first stumbled on a prototype Cinema 11 at the annual Expo of the Custom Electronics Design and Installation Association, I was impressed by its small size, sleek lines, and intriguing features. Although it lacked any video inputs or video processing, it was Dolby-HD compatible, and had room equalization (EQ) and a 7.1-channel analog input that could be bypassed or digitized. As it turns out, the production version contains all of these, though not exactly as I'd imagined them. In the broadest…

Music in the Round #25 Recordings In The Round: Special Opera Edition

Sidebar: Recordings In The Round: Special Opera Edition

RUED LANGGAARD: Antikrist
Soloists: Sten Byriel, Helene Gjerris, Morten Suurballe, Jon Ketilsson, Johnny Van Hal,
Poul Elming, John Lundgren, Susanne Resmark, Camilla Nylund, Anne Margrethe Dahl. Thomas Dausgaard, Danish National Symphony & Choir.
DaCapo 6.220523-24 (2 SACD/CDs)

Fasten your seatbelts! From the spine-tingling opening through passages of power, beauty, and even great nastiness, the opera Antikrist, by Danish composer Rued Langgaard (1893–1952), stands, for me, as the latest in a historic series…

Listening #55

When audio designer Ken Shindo was a little boy, his father kept an enormous collection of 78rpm records in their home in Tokyo. During the final days of World War II, the Japanese authorities did their best to evacuate the city, but the elder Shindo was steadfast: He refused to leave, for fear that the records would be gone when he returned.

The evacuation was inevitable, and the worst came to pass: Virtually all of the family's belongings were destroyed. Yet by the end of 1947, according to one of Ken's sisters, the record collection had been replaced entirely—and a fine new music…

Listening #55 Page 2

Equally impressive—and altogether unexpected—was the Montille's extraordinarily high value for the money. I've opened its chassis a number of times and marveled at the Montille's build quality, not to mention the provenance of its parts. More important, I've listened to it for hours on end, and been thoroughly enchanted by this little amp's performance every single time I've powered it up. To think that so unique and musically superior a design, hand-built to such a high level of quality, can sell for only $3995 is nothing short of wondrous.

Shindo Masseto preamplifier
So there I…

Heavy Load: How Loudspeakers Torture Amplifiers

Why, in loudspeaker reviews, is impedance measured (assuming that the magazine in question bothers to measure anything)? Generally, for one principal reason only: to establish whether the speaker presents an "easy" or a "difficult" load to its partnering amplifier. In the design context, much more information can be extracted from a graph of speaker impedance vs frequency—such as details of the bass alignment, and indications of internal or structural resonances that can be difficult to identify by acoustical measurements. But for a magazine audience, the principal interest in a loudspeaker's…

Heavy Load: How Loudspeakers Torture Amplifiers Page 2

All this was clear from Eric Benjamin's aforementioned AES article, but the message seems not to have filtered through in the 13 years since (footnote 5). Loudspeaker impedance continues to be assessed by considering modulus and phase separately when, as Benjamin showed, there is a much better way to reflect the load's severity from the amplifier's viewpoint. What he did—as Douglas Self did later (footnote 6), though by the less elegant means of SPICE circuit simulation rather than mathematical analysis—was to plot peak output-stage power dissipation vs frequency with respect to a stated…

Heavy Load: How Loudspeakers Torture Amplifiers Page 3

So is this the real Otala effect we are looking at here? Do some speakers present more difficult loads than their impedance measurements suggest, not because of a failure of conventional measurement but simply because the data are not interpreted properly? To be certain about this, we must do what Otala and his coworkers failed to do: put the idea to the test using representative music signals. Eric Benjamin performed this crucial reality check and concluded that the dissipation behavior depicted in figs.5–10 is relevant to music signals. Let's see if we achieve a similar result using a…

Recording of June 1992: <I>Nevermind</I>

Nirvana: Nevermind
Geffen/Sub Pop DGCD-24425 (CD only). Butch Vig, Nirvana, prods. AAD. TT: 59:22

I was driving home from work the other day when I saw a group of three boys, all around 13, sauntering down Guadalupe all attitude, wearing ratty skateboard chic and holding their skinny-ass arms out away from their sides like they were too muscular to swing freely. Nothing very extraordinary as far as 13-year-old boys go. But just as they got to the corner, one of the boys took a running leap and karate-kicked the massive steel signal-light pole. I mean, he whaled that sucker. It being…