B&K ST140


Author: Karsten Hein

Category: Gear & Review

Tag(s): Power Amplifiers

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B&K Components Ltd. was founded by John Beyer and Steve Keiser in Buffalo, NY, in 1981. The company evolved out of a single amplifier design that Steve Keiser had created attending electrical engineering school during his final year of college. Upon showing his amplifier to John Beyer, who was thinking about putting together a stereo system for his own use, John was so overwhelmed by the performance of the unit that he convinced Steve they should found a company together to market it. Initially, all units were built by hand and by the new owners themselves. From the time of the Chicago CES show, where the products were first shown to the greater public, John Beyer acted as sales and business director, and Steven Keiser performed all technical functions.

The first amplifier was to be called the ST-140 and was poised to become an instant success with audiophiles, due to its musicality and its relatively affordable purchasing price. The first version of the ST-140 was a 70 watts per channel into 8 ohms design using a standard iron core transformer. The model shown here is the updated version featuring a toroidal transformer and 105 watts per channel into eight ohms. Right from the beginning, the ST-140 followed a ‘less-is-more’ approach that makes it the ideal playing ground for music enthusiasts. While many things can go musically wrong with such a design, the right setup and combination of accessories will easily lead to a highly engaging because unfiltered musical experience.

Over the years, B&K have derived most of their income from Original Equipment Manufacturing (OEM) designing, engineering, and manufacturing products for other electronics companies and to be sold under their various brand names. The company has manufactured many amplifiers and other components that were sold under brand names such as Crestron, Harman / Kardon, Lexicon, and Onkyo Integra Research.

The ST-140 is a simple Dynaco inspired design that is able to perform into low ohm loads, an important criteria when driving ‘difficult’ speakers, such as electrostatic or magnetostatic designs. This is especially true for the revised 1989 version of the amp. It offers great musical balance and dynamics and in this sense can really ‘sing and breathe’ though a musical performance. When comparing a design like the ST-140 with more sophisticated amps, such as the higher powered Harman / Kardon Citation 22 (200 watts per channel into 8 ohms), the transparency and musicality of the smaller ST-140 is truly astounding.


  • Type: Solid-state stereo power amplifier
  • Manufacturer: B&K Components Ltd., Buffalo, NY
  • Output power (RMS, 8 ohms): 105 watts per channel
  • Total harmonic distortion (5 Hz - 45 kHz): 0.09%
  • Frequency response: 3 Hz - 70.000 Hz.
  • Year: 1989, revised 105 watts version
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