Tube Preamp Reviews

In just a few years, Sonic Frontiers has evolved from a parts and kit vendor to a full-line audio manufacturer (footnote 1). Their initial offerings were well received, but their kit origins were apparent in the layout and cosmetics of their products. While SF still offers kits (like their high-value Assemblage DAC-2), the new line of vacuum-tube electronics has world-class construction, design, and packaging. This generation of SF equipment is evidence of their advanced evolution, even though their constructor genome can be detected in the use of audiophile-preferred, as opposed of OEM, components.

How important is the use of balanced circuit typology in the design of preamplifiers and power amplifiers? Ask the top audio designers (I didn't, but just play along, okay?) and you'll get a wide variety of opinions. Some reject the balanced approach outright, arguing that it represents a needless duplication of circuit components, and that better results can be achieved if the same attention and resources are devoted to perfecting a single-ended circuit. In his provocatively titled article "Balance:">http://www.stereophile.com//features/335/">Balance: Benefit or Bluff?" (Stereophile, November 1994, p.77), Martin Colloms questioned the advantages of balanced designs, suggesting that while the results may be better in certain respects (eg, noise level), the reproduced sound may suffer in other, perhaps more important ways (eg, rhythm and dynamics).

From the front, the LS5 looks identical to Audio Research's popular LS2: two knobs on either side of the Audio Research nameplate, and a row of toggle switches along the bottom. But that's where the similarities end; the LS5 is a completely different animal from the LS2, or even the balanced LS2B.