Cary SLP-98P tube preamplifier

I had it all wrong. I assumed that the "SLP" in SLP-98P stood for stereo line preamplifier. But Dennis Had, Cary Audio's founder and chief designer, told me that it actually stands for sweet little preamplifier. In a day and age when acme is a word without meaning and the fighting Irish are neither, this strikes me as a risky marketing gambit—but one that may be effective if the name proves true.

For their part, the numbers are more objective: The first preamp in this series, the Cary SLP-90, was designed in 1990. Its successor, the SLP-94, was designed in 1994 (I reviewed it in Listener magazine in 1996). Can you guess the age of this, Cary's most recent preamp design—and how far behind the curve I am in writing about it?

The SLP-98P, though physically similar to its predecessors, is a different design from the ground up. It uses tubes for voltage gain and buffering only, not for rectification or regulation. And for the first time in Cary Audio history, their flagship preamp is built around the well-loved 6SN7GT, a husky dual-triode from the 1940s that's become popular in recent years as one of the single-ended-triode (SET) input tubes of choice. The SLP-98P uses two of these per channel, as line-level gain amps and cathode followers, for low output impedance.

Like its predecessors, the basic SLP-98 is available with or without an onboard phono preamp, and while the culturally impoverished can opt for a line-only version—the Cary SLP-98L, which retails for $3100—the SLP-98P reviewed here incorporates pairs of 12AX7 and 12AU7 tubes, for phono gain and buffering, respectively. Covers for the phono tubes, to help prevent microphonics, are a part of the deal, as is RIAA equalization, of course, and a patch of mu-metal shielding on the chassis. Dennis Had points out with glee that, these days, the phono version of his preamp outsells the line-only version by ten to one; not so long ago, the opposite was true.

Also like its predecessors, the newest Cary preamp uses a separate box to house its power supply, containing as it does a frame-type transformer, a choke, and two good-sized smoothing capacitors (together comprising a Pi filter of the usual sort), six regulators, a rectifier bridge, a relay, and other bits. These are connected to the preamp itself through a multi-conductor umbilical cord with threaded connectors at both ends. The power supply isn't dual-mono throughout, but it does have separate regulators for the two channels' filament and B+ voltages.

In what has become a recent Cary tradition, the chassis of the SLP-98P is painted in an automotive finish—a stunning Chinese red from the nice people at Jaguar, in this case—and hand-rubbed to a lustrous fare-thee-well. This, combined with the fact that the Cary preamp is only as large as it needs to be and forgoes the silly pretense of rack-mounting, results in a preamp of greater than average beauty, I think.

To is a preposition
Back inside: Except for the bits associated with the Cary's remote control, everything here is hard-wired, point to point. This is a labor-intensive way to build a preamp, and I admire its finished appearance as much as I assume the SLP-98P is made that way for sonic reasons, above all. (I continue to wonder whether signal integrity suffers from the discontinuities of wide, flat PCB traces as compared with round wire of a relatively small gauge, which is more like the leads of all the passive parts in the circuit—all the while tipping my hat once more to Dennis Morecroft for making the same observation at least two decades ago.) Terminal strips are fastened to the inside of the chassis using a variety of means, including nuts and bolts, self-adhesive standoffs, and epoxy. The chassis itself is well-crafted, and the parts quality is fine if not boutique-y. (Cary does, however, offer stylish oil-filled coupling capacitors at extra cost.) Four tallish, Sorbothane-like feet are bolted to the sturdy bottom cover.

The SLP-98P has a volume/balance-control scheme I enjoyed using. The signal begins its journey at a pair of 100k ohm pots (one for each channel), which provide a full range of channel-specific attenuation for adjusting balance. From there it goes to a nice Alps pot, piggybacked by a little electric motor for the remote. The selector switch is a five-position rotary affair, and there are separate two-way toggle switches on the front panel for muting and the tape monitor. The back row has the five pairs of input jacks, plus monitor loop and two pairs of outputs. Subwoofer users, rejoice; mono enthusiasts, hang down your heads and cry.

The remote handset is bare-bones but useful, with four soft-touch buttons: volume up and down, mute on and off. The remote mute is in addition to the front-panel mute switch, and obviously addresses a separate relay for this purpose: switching the mute from the handset does not physically move the front-panel switch. If the preamp has been muted using the front-panel switch, you can't unmute it with the remote handset; on the other hand, it's possible to double-mute the SLP-98P, for an extra margin of safety with software that's very, very bad.

The Cary's controls are so complete and well-thought-out that I feel like a grump for voicing this complaint: The Tape Monitor switch is somewhat counterintuitive, for two reasons. First, for normal listening, the switch must be flipped to a position opposite that of the mute switch next to it; ie, in order to play music, while one switch is pointed up, the other must be pointed down. Second, to play music, the monitor switch must be flipped to the position marked Tape. This really confused the heck out of me until I realized that, in this instance, tape is meant as a verb, not a noun. My English degree comes in handy from time to time after all.

I used the Cary preamp with my own SET amps—the Fi 2A3 Stereo and Audio Note Kit One—and, thanks to a loan from EAR USA, I was able to try it with that company's lovely 890 amplifier, as well. [Art's review of the 890 will appear in our April issue.—Ed.] Thus I can say with confidence that the SLP-98P didn't appear to perform differently into mildly different loads. Because the Cary is described as phase-inverting on both its line and phono inputs, and because all the amplifiers I used with it are not, I made sure to reverse cable polarity at both loudspeakers before listening, in order to preserve the integrity of the music waveform's precise shape to whatever extent was possible. Of course, that assumes that the music selections I made during that time—capriciously and at random, as always—comprised more phase-correct recordings than phase-incorrect ones (or, more perniciously, multitrack recordings made up of both), which is an assumption of no great pedigree.

Powering up the Cary is an exercise in gratification deferred, but a prudent one. A master switch on the outboard power supply gets the AC flowing through its transformer and Pi filter, but only after the rotary power switch on the preamp itself is turned one click do the smaller regulators begin to power up the various tube filaments: a standby mode for keeping the tubes warm but otherwise unperturbed. Turning the power knob one more click to the right gets the rail voltage flowing; the SLP-98P is now ready to play.

The SLP-98P's phono section had sufficient gain for the one moving-magnet cartridge I tried with it—a nice old Rega Elys—and it worked well with Dynavector's entry-level, high-output moving-coil cartridge, the 10x5, which I reviewed in Stereophile's October 2003 issue, and which I'd better send back or buy soon before this magazine's sage critics link me to international terrorism or the kidnapping of the Lindbergh baby. On its own, however, with the low-output MC cartridges I usually use, the Cary's phono section couldn't quite cut the mustard. So I combined it with my own Audio Note AN-S2 step-up transformer and a borrowed Tamura L2-D transformer, which is quite good. I really like step-up transformers, anyway.

Sound is a verb
I wouldn't hesitate for a second to describe the Cary SLP-98P as sounding like a tubed preamp, notwithstanding such stereotypically untubey characteristics as the Cary's clear (if pleasantly full) lower octaves and overall excellent rhythm and pacing. With all sources, the musical colors passed by the SLP-98P sounded rich to me—not at all lacking in air or believable treble sparkle, but nonetheless distinctly velvety throughout the mids. I mean that in a positive way, of course: a compliment in this wayward age of needlessly complex hybrid circuits that, often as not, make pianos sound like trash compactors and voices like alarms.

Footnote 1: On the old mix as well, the floor tom is used to fill in for an absent electric bass—which it does, but barely. It sounds to me like someone lost their nerve during the recent remix, perhaps assuming that modern listeners would be less willing than their elders to accept such a relatively "lean" sound.—Art Dudley
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