Solid State Preamp Reviews

I asked for a sample of the K-5xe so I could do a Follow-Up to Sam's review, but other review commitments kept getting in the way. When I finally spent some time with it (S/N 10J002), I found the sound a little on the robust, forward side, which made system matching problematic. Then, as I was about to spill some ink on the K-5xe, I got an e-mail from Charlie Hansen letting me know that the development of the QB-9 USB DAC had led them to rethink the K-5xe's design, and that Ayre would be sending a sample of what would be called the K-5xe^MP. After a longer delay than I had anticipated, the K-5xe^MP, priced at $3500, arrived for review.

Cycles can be seen in the fortunes of companies. Likewise cycles can be seen in the performance of companies' products. A particular range will appear to have got it just right, whatever "it" is. The designer may have hit a winning streak and thus steal a lead over the competition. C-J set a new state-of-the-art preamp standard in the late 1980s with their Premier Seven, and some of that expertise and experience are beginning to pay off in the shape of new high-performance preamplifiers at realistic prices. Two important products have emerged from all this in C-J's moderately priced FET range, namely the PF-1 preamp and the matching MF-200 power amp. By audiophile standards, these are moderately priced at $1295 and $1995, respectively.

Compared to the Krell KSA-300S power amplifier that I also review this month, the KRC preamp's design is, at first glance, almost conventional. But its thoroughly high-end internal design has been equally well thought-out and executed. Its main, four-layer, glass-epoxy circuit board is for the audio signal, DC power, and ground—two layers for the latter are said to minimize noise. The gain stages are pure class-A and complementary. As in the amplifier, the circuit is direct-coupled, with servo circuits controlling the DC offset. The fully regulated power supply is housed in an external chassis. Seven inputs are provided: four single-ended, two balanced, and one single-ended tape. All inputs are line-level except for the optional, single-ended phono stage. (This review will address the line stages; a Follow-Up will discuss the phono stage's operation.) There are three outputs: balanced and single-ended main outputs, and a single-ended tape output.

Before launching into Stereophile's first-ever report on a Mark Levinson product, an important point needs to be clarified. Although Mark Levinson products were originally made by Mark Levinson, they are no longer. Au contraire, Mark Levinson products are now being made by Madrigal, Ltd., which bought Mark Levinson Audio Systems' assets and trademark two years ago. Mark Levinson's products, as distinguished from Mark Levinson products, are now being manufactured by a company called Cello. But the subject of this report, the Mark Levinson ML-7A preamplifier, is a product of Madrigal, Ltd., not of Cello. Now that I've made that all perfectly clear, we may proceed.

Even as Robert Harley was writing his Stereophile reviewhttp://www.stereophile.com/solidpreamps/mark_levinson_no38_preamplifier…; of the $3995 Mark Levinson No.38 remote-controlled line preamplifier (it appeared in August '94, Vol.17 No.8, p.98), Madrigal Audio Laboratories announced an upgraded, cost-no-object version, the No.38S (footnote 1). At $6495, the 'S is significantly more expensive than the junior version; although it uses the same chassis, power supply, and circuit topology, it's in all other ways a different preamplifier.

Threshold is one of the longest-surviving high-end audio companies. Founded in the 1970s by Nelson">http://www.stereophile.com/interviews/1191pass">Nelson Pass and René Besne, it was acquired by a large, publicly traded corporation in 1988. This had both positive and negative results in that Threshold was then able to expand its activities, adding the cost-effective Forté line of products, but energies were drained away from cutting-edge design. Besne left the company in 1991, while Pass resigned in 1992 to pursue other interests. (These blossomed into the Pass Aleph 0 amplifier reviewed by DO in March '95, Vol.18 No.3.)

Over the years, I have become increasingly impressed by the quality of the audio engineering emanating from Simaudio, which next year celebrates its 30th anniversary. In a world where the US facilities of some well-known audio brands have been reduced to a design office coupled to a warehouse for storing product manufactured overseas, this Montreal-based manufacturer, in order to keep full control over quality and hence reliability, does as much manufacturing as possible in-house, including metalwork, some printed circuit-board stuffing, and assembly. (See my photo essay starting herehttp://forum.stereophile.com/photopost/showphoto.php/photo/856">here;.)