Solid State Preamp Reviews

Introduced at the 1988 Summer CES, this preamplifier from San Francisco-based Parasound costs $395 and is manufactured in Taiwan. It does away with mechanical switching for source select and tape functions, replacing it with CMOS integrated-circuit switches similar to those used in the British Linn LK1 and Quad 34 and 44 models. Construction is to a good standard and the circuit is carried on two main pcbs and three small ones. Following a signal from the phono inputs, the MM-only RIAA amplifier is based on discrete FETs, its output joining the line-level signals at the switching ICs, these controlled by DC voltages controlled by front-panel pushbuttons.

In the March 2018 issue, Art Dudley admired the sound quality of Ayre Acoustics' KX-5 Twenty preamplifier, but didn't love some of its operational aspects. I've staged this Follow-Up as a putative face-off between the Ayre and my current reference preamplifier, the PS Audio BHK Signature, which I reviewed in the June 2017 issue.

Each equipment report in Stereophile focuses on a single audio component. When listening to a component for review, I leave unchanged all other components in my audio system. Other Stereophile reviewers experiment with different interconnects, speaker cables, power cords, or stands. As I found while reviewing Bryston's BP-17³ (Cubed) preamplifier, being flexible has its rewards.

Description
My first lesson in flexibility was learning what Bryston means by "Cubed" (footnote 1). Jim Tanner, Bryston's VP of sales and marketing, explained that all their Cubed models employ an array of 12 active devices for the first 6dB of gain. Developed by the late Dr. Ioan Alexandru Salomie, this array acts as "a super-linear" input buffer to filter out audio- and radio-frequency noise, particularly anomalies that originate in the power line, reducing the overall noise and distortion to less than 0.001%.

I have not been attending audio shows as often as I used to, and this January, for the first time in more than 20 years, I'm skipping the annual Consumer Electronics Show. My personal return on investment has become hard to justify, especially when attendance at each annual CES requires a round trip from New York City to Las Vegas, Nevada. More important, audio shows now seem focused mostly on either two-channel music playback or multichannel home theater, whereas what interests me is listening to music in surround sound.

Classé Audio's flagship preamplifier, the Six, has enjoyed a five-year life span—quite long for an audiophile component. Company president Glen Grue reports that the Six's sales have continued to improve during that time. How to explain this solid-state preamp's continued success in competition with today's newer, remote-controlled, line-stage preamplifiers?

The KSL ($1800, $2100 with phono section) is a one-box line controller/preamplifier, just 2.25" high, with a nominal voltage gain of 10dB, or 3x. Despite its moderate price, the KSL is distinguished by having balanced outputs (via industry-standard XLR connectors), as well as two balanced inputs. Conventional single-ended, unbalanced outputs are also available via a pair of gold-plated phono sockets. Two unbalanced inputs are provided, plus a third via the tape monitor switch.

"As the original L2 circuitry was virtually flawless, it was the emergence of new electronic components that opened up a possibility of [even better performance] . . ."

So begins one of two booklets—one a collection of specifications and interior photos, the other a distinctly thorough user's manual—included with the new L2.1 Reference line-level preamplifier from Brooklyn's Lamm Industries, earlier products from which have impressed me as among the best available. Indeed, coming from almost anyone else, the above quote would strike me as trivial boasting—but I know from experience that there's nothing trivial about designer and company head Vladimir Lamm.