B&K ST-140 power amplifier Sam Tellig 1985

Sam Tellig wrote about the ST-140 in December 1985 (Vol.8 No.8):

I've been meaning to write about the B&K ST-140, but keep getting sidetracked. Well, the Steve Kaiser/Frank Van Alstine flap (footnote 1) gives me an excuse.

Seriously, I wouldn't want to see this controversy—essentially a feud between B&K's John Beyer and his ex-partner, Steve Kaiser—obscure the point that B&K products are among the finest values on the market today.

JGH reported the B&K ST-140 one of the best amps under $1000 two years ago; I think it's one of the best amps, period. That's startling when you consider its $440 price. It may well have some sonic competition from a new 100Wpc Adcom, expected to retail for around $400, but I have a hunch the ST-140 will hold its own. It has against the Threshold S/150, Quicksilver Mono Tube Amps, and the New York Audio Labs Moscode 600—all in the $1000+ price category.

Other showdowns: the ST-140 is more dynamic than the NYAL Moscode 300 ($899), and sweeter, less grainy, and more dynamic than the Tandberg 3006A ($995). And, as a bonus, the B&K even looks good, whether in black with gold handles, or all gold.

Rated at "only" 70Wpc, the B&K packs the tremendous dynamic punch of a far more powerful amp—it's been able to drive anything I asked it to. Superb with Spendor SP-1s, and equally outstanding with Quad ESL-63s, the ST-140 is probably the best amp I have used with the Quads, including the Quicksilver Mono Tube amps. It makes the Quads sound dynamic—even gutsy—yet the midrange is silky-smooth and sweet.

Compared to the Eagle 2 ($895), the B&K is slightly less detailed but just as dynamic, if not more so (footnote 2). There isn't the same richness of harmonic information, but there is a greater mellowness and richness of sound. The Eagle is like an excellent modern concert hall—crisp, clear, exceptionally clean. The B&K is more like Carnegie Hall—warm, rich, but with a very slight tendency to soften detail. In other words, tubelike. (The B&K uses MOSFETs in the output stage.)

The B&K is no slouch when it comes to reproducing low-level information, though—particularly from compact discs. You hear things—very soft bass drum beats, for instance—that you can hear with few other amps. The bass is better than I've heard from other MOSFET designs.—Sam Tellig

Footnote 1: John Beyer says he can document that the ST-140's circuitry is unique. But what if he had borrowed from Van Alstine? It's common practice for engineers to borrow elements of circuit design. In fact, it's virtually impossible not to do so—you can't reinvent the wheel every time you design a new amp. (It's apparently very difficult to patent electronic circuitry. This is a good thing; engineers would otherwise be severely hamstrung.) As far as I know, neither Steve Kaiser nor Frank Van Alstine is charging John Beyer with patent or copyright infringement. It seems to me that Kaiser is out to settle old scores, and maybe even scuttle the company—a bad case of sour grapes. B&K produces great products at terrific prices. When you get your stereo gear out of the box and hook it up, that's what really matters.—Sam Tellig

Footnote 2: On full-range speakers with significant output below 40Hz—this would not include Spendor SP-1s or Quad ESL-63s—the B&K we have here in Santa Fe is no match for the Eagle at the low end. Also, the Eagle's high end tends to be clean and extremely extended, while the B&K is a little softer. At the high end, it's a matter of taste and matching your speakers.—Larry Archibald