Integrated Amp Reviews

In July 2000, I reviewed the Mark Levinson company's first integrated amplifier, the No.383, and found that its sound had "clarity, transparency, liquid mids and highs, with dynamic contrasts." Also evident were the No.383's power-output limitations, the result of building large power supplies and heatsinks into a single case that had to fulfill multiple functions. Still, the No.383's price of $5900 was much less than the total cost of the equivalent in Mark Levinson separates. Later, in April 2007, I reviewed a similarly powered integrated amplifier, Bryston's B100-DA ($3195), which included a built-in DAC.

Nuvistors—miniature, small-signal, vacuum tubes made of metal and ceramic—were introduced by RCA in 1959, at the dawn of the transistor revolution. RCA used them throughout the 1960s in its New Vista line of television sets, mostly in the tuner section. But by the early 1970s, solid-state devices had all but replaced tubes, nuvistors included (with a few notable exceptions). Ampex based the electronics of its well-regarded, late-'60s MR-70 open-reel tape deck on nuvistors, which were also used in microphone preamplifiers—in both cases for their very low noise and reputation for reliability and long life. For a time, Conrad-Johnson used them as well. While nuvistors may seem exotic today, they're hardly rare. On eBay you can find for sale hundreds if not thousands of used and new-old stock (NOS) nuvistors, as well as nuvistor sockets, without which the tubes are less easy to implement. (But they can be, and often are, hard-wired into a circuit.)

As an audio scribe, the fiercest demons I wrestle are beliefs—yours and mine; those of my friends, my editors, my fellow reviewers; and those of the engineers and promoters of the products I write about. Sometimes the force of these rabidly held and (mostly) conflicting beliefs paralyzes me with self-doubt: What do I know? What makes me qualified to listen and judge?