Features

Remember the old mathematical riddle about moving a football from a hundred yards out to the goal line? Known as Xeno's Paradox, it goes like this: if each time the ball is moved it travels half the distance to the goal, how many moves will it take to get there? The answer: an infinite number, because no matter how many times you cut the distance to the goal by half, you'll always be some infinitesimal distance away from it.

In the last two years, the available choices in 300B output tubes for one's low-wattage single-ended power amplifier have become an embarrassment of riches. If we include the souped-up versions—which, in fact, deviate from the original 1930s Western Electric (WE) specifications—the number of 300Bs to choose from now includes about 15 different brands and types.

Jim Austin briefly discusses MQA in his review of the Explorer² in this issue, but a more complete description of MQA can be found in an article posted on Stereophile's website at the end of 2014.

MQA involves two fundamental concepts, discussed in a paper presented to the Audio Engineering Society in October 2014, the first responsible for a potential improvement in sound quality, the second responsible for a large reduction in the bandwidth required for storage and streaming of high-resolution files...

If there's one buzzword in high-end audio for the 1990s, it's undoubtedly jitter. "Jitter" describes timing variations in the clock controlling the ones and zeros that represent the analog audio signal. If that clock isn't stable to an extraordinarily precise degree, the sound quality of the digital processor will be degraded.

A CD transport/digital processor combination introduces jitter in three ways: 1) the transport puts out a jittered signal; 2) the S/PDIF or AES/EBU interface between the transport and processor creates jitter; and 3) the digital processor adds its own jitter to the clock. These additive factors are largely responsible for the great range in sound quality we hear from different transports and interfaces.

When I need information about recordings, I go to Discogs. At Discogs, Kevin Gray has more than 2500 entries. That's as good an indicator as any of the amount of ground he has covered in his career so far as a creative participant in the recorded-music art known as mastering. Since starting out in the early 1970s, in Los Angeles, he has worked for all the major music labels and many independents, in all music genres.

One evening late last summer I took the most expensive workout of my life. In my hurry to meet a friend at the gym, I left the house, leaving my computer and hi-fi on despite the ominous look of the sky. In the South, experience teaches you to dash about disconnecting everything at the first sign of a thunderstorm. Usually I do, but this time my mind was elsewhere.

"Without content, television is nothing more than lights in a box."
---Edward R. Murrow.