Audio Research SP9 preamplifier Guy Lemcoe SP9 Mk.II 12/90

Guy Lemcoe reviewed the SP9 Mk.II in November 1990 (Vol.13 No.11):

Is it possible to get outstanding sound from a preamplifier which costs under two grand? In today's high-end arena, cream-of-the-crop preamps sell for two, three, even four times that amount. You can easily spend two kilobucks on cables—or a cartridge! It wasn't too many years ago that you could assemble an entire system for not much more than $2000 and get credible, if not outstanding, sound. Today the stakes have changed. Thanks to publications such as Audiomart, it's still possible to assemble a fine system using components others have cast aside. If you're looking for new equipment, however, prepare for a shock. Creative design and its thoughtful execution, coupled with the use of technologically superior parts, have led to the existence of hi-fi components which bring the musical experience closer to the listener than ever before, though the cost of admission to such glorious music-making has usually been prohibitive for most consumers. Fortunately, Audio Research's SP9 Mk.II can be had for under two kilobucks and presents, in its own unique way, a strong challenges to components costing much more.

Audio Research doesn't need any introduction to Stereophile readers. It has consistently enriched the lives of music lovers with reliable, good-sounding electronics which stay out of the way of the music. The hybrid SP9 Mk.II uses two 6DJ8 tubes, one in the phono stage and one in the line section, each ringed with tube dampers, like the solitary 6DJ8 in the ARC SP14.

The SP9 Mk.II is a revision of the original SP9 introduced in the Summer of 1987, embodying what Audio Research calls a group of 14 different improvements. J. Gordon Holt gave a listen to the original SP9 (Vol.10 No.8) and came away disappointed. So did John Atkinson. Is the SP9 Mk.II a better preamp? Read on.

The SP9 Mk.II looks a lot like its big brother, the 66%-more-expensive SP14. My sample came in the optional black finish and looked good, though I prefer Audio Research's traditional silver look. The dull silver lettering on the $s3?/?1?6"-thick black front panel is not easily legible in dim light. A centrally located LED glows green to indicate the unit is on, and will dim when the mute switch is thrown. Two of the knobs—Attenuation and Rec Out—and four of the toggle switches which graced the SP14's front panel have disappeared from the SP9 Mk.II. Attenuation is used on the SP14 to adjust the level of the input signal so that the Gain control can be set to its optimum mid-rotation or high position. This was especially useful when playing CDs, as players and processors vary in their output levels. The SP9 Mk.II has addressed this situation by reducing the gain of the CD input by 12dB. In my system, with the CAL Tercet Mk.III or Tempest II Special Edition players, I found I could get realistic volume levels with the gain control of the SP9 Mk.II set straight-up. This also happened to be the most appropriate setting for phono reproduction with my AudioQuest 404i-L moving-coil cartridge (0.5mV nominal output).

The Rec Out selector knob on the SP14 enables the user to record from one source while listening to another. Its absence from the SP9 Mk.II, to me, is not serious. Neither is the lack of Attenuation. So on the SP9 Mk.II you get the basics: Gain (stepped), Balance (stepped), Mode and Input selection.

The most conspicuous of the missing toggle switches are Bypass and Outlets. Since the SP9 Mk.II has no convenience outlets on the rear of its chassis, a switch to direct power to them is not necessary. However, the lack of a Bypass switch means that signals are routed through the circuitry and cannot be "hot-rodded" to the main outs. I miss this feature. You can hot-rod the SP9 Mk.II for phono replay by taking the signal from a tape-out jack—there is no active circuitry or buffering between the line-level inputs and the tape-out jacks—but you'll then have no control over volume level unless you run from the tape-out into some sort of interface such as those from Electronic Visionary Systems or Reference Line. Remaining on the SP9 Mk.II are toggles for Power, Mute, Tape 1/Tape2, and Monitor/Source. I feel this configuration represents the minimum degree of control desired by audiophiles. The rear panel of the SP9 Mk.II looks identical to the SP14's, with the exception of a missing pair of main-out jacks (precluding practical bi-amping). Two sets of tape-out jacks are furnished. Solidly mounted, female gold-plated Tiffanys are used for all inputs and outputs.

Changing the impedance of the phono inputs for MC cartridges—47k ohms is standard—is as awkward on the SP9 Mk.II as it is on the SP14. You must turn the unit over and remove the bottom cover to locate the turret terminal posts on the bottom of the main circuit board (near the phono inputs). The desired resistors (supplied, along with a special-alloy solder) must then be soldered to these posts after first wrapping the resistor leads around them. This arrangement does not encourage cartridge-loading experimentation. It's also possible to reduce the gain of the line section by 6dB via an internal provision requiring a soldering iron.

Construction quality is typical of Audio Research—among the best in the business. The power-supply transformer is a large toroidal located well away from the phono section. Alps potentiometers are used for the volume and balance controls. Rel-Caps, Wonder Caps, and Wima parts are evident on the neat and tidy PC board. Solder traces are wide, in usual Audio Research fashion, and the joints well made.

SP9 Mk.II sound
I was anxious to compare the sound of the SP9 Mk.II to its big brother, the SP14. I was quite taken with the SP14 (giving it a rave review in Vol.13 No.6), and was curious to see if the "magic" I had become aware of in its ability to communicate a musical experience had been passed down to its less dear sibling. Before doing so, I listened to the SP9 Mk.II alone to get acquainted with its sound. Since I cling so tenaciously to analog, it's only natural that an LP be the first source of music for this audition.

As I expected, the SP9 Mk.II produced a fundamentally good sound in my system, with clear, sparkling highs and a rich, if somewhat reticent, midrange and bass. There is a family resemblance between this product and the SP14, especially in the overall "musicality" of the sound. I felt I could listen to the SP9 Mk.II for extended periods without listening fatigue. Timbres of instruments were well-captured, and male and female voices sounded good. Retrieval of fine performance details was excellent, and the recreation of the recording venue was fine, though somewhat attenuated at the rear and edges of the stage.

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