Cary SLP-03 Preamp CAD-120S II Power Amplifier (TAS 208)

Equipment report
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Solid-state preamplifiers
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Cary Audio Design SLP-03
Cary SLP-03 Preamp CAD-120S II Power Amplifier (TAS 208)

Normally, I try to avoid dragging readers through the problems I have in obtaining equipment and making it function. In this case, however, I would do a distinct disservice to any audiophile looking for a great tube amp with truly musical sound, and to any audiophile who already has a Cary CAD 120S and has problems with it. My experience led to the redesign of the Cary CAD 120S and the creation of the Cary CAD 120S II, and if you have read negative “chat” about the original 120S you really need to know what happened.

The Road from the Cary-120S to the Cary-120S II

My original interest in the Cary CAD-120S began largely as a result of specsmanship. I had previously been using moderately powered tube amplifiers from PrimaLuna and VAS (the Citation One) as part of my reference system that depended on RCA inputs. Both worked very well, but I needed two things: More power than most audiophiles need, since a reviewer never can predict the sensitivity of the speakers that come in for review, and balanced inputs for compatibility with the wide range of equipment coming through my listening room.

That was the initial reason I became interested in the Cary CAD-120S. It provides 60 watts per channel in triode mode and 120 watts per channel in ultralinear mode into an 8-ohm speaker load. It also had good specs by tube standards in many other respects. (These are described in detail in the specifications listings at the end of this review.) The input circuit is a fully balanced design with separate RCA and XLR inputs; it uses 1% precision metal resistors, Kimber capacitors, and the power supply features 1120mF of capacitance for ample reserves in demanding usages. In short, the Cary CAD-120S had all the bells and whistles of a top quality design.

As for features, I was struck by the fact that, the output stage could be switched “on the fly” from triode mode to ultralinear by using a front-panel selector button, without turning the amp off and on. It also had a soft-start turn-on circuit to extend tube life, and backlit front-panel meters to show the circuit bias setting for each channel and whether it was operating correctly.

Specs are one thing, however, and reality is another. I quickly found I had serious problems with the review sample, and largely because of gain. While the Cary 120S seemed to be advertised as an amplifier that could be used with the normal range of preamps, the truth turned out to be very different. The amplifier simply did not have the gain to work with either my Pass or Quad 909 preamps. The result was it was not only impossible to take advantage of the 120S’s power, but the sound suffered from all of the typical problems that occur when there is a serious gain mismatch between components of this kind. The sound lack life and dynamics; there was no air and finer soundstage detail, and—to mix a metaphor—the music sounded “shut in.”

Enter the Cary SLP-03 Preamp

It had been a long, long time since I had encountered gain mismatch as a problem, and the specs for the 120S did not tell me enough to suggest the cause. Accordingly, I asked for the loan of a Cary preamp and got the SLP-03. Once again, the specs were impressive. The SLP-03 is not an exercise in audio minimalism. All audio path signals are amplified through 12AU7 vacuum tubes in a Class A zero-feedback circuit. Its circuit is a fully balanced design with four analog gain stages: Two separate gain stages are used for each of the two channels. One gain stage amplifies the positive phase and the other gain stage amplifies the negative phase. The two stages for each channel represent the four active line circuits. It also has eight fully regulated power supplies with separate supplies for each channel's analog circuit along with power supplies for the display and dual supplies for the Motorola processor.

The SLP-03 has a fully functional remote control, and a far wider range of inputs and outputs than many competing tube preamps. These include one pair of XLR balanced inputs, and six pairs of RCA inputs; one pair of XLR balanced outputs, and two pairs of RCA outputs. There are wide range of other features like a tape monitor loop, cinema bypass, an RS232 full remote configuration interface, and power-amplifier triggers. Unlike far too many newer tube preamps, it also had a balance control—a feature I find essential in getting the best imaging out of a given recording and that leads me to reject any design that lacks a balance control.

The only problem was that the Cary SLP-03 had the same gain problems as my Pass and Quad preamps. In short, I was right back where I started. I supposed I should have caught the gain problem earlier, but I now got far more serious about finding out what was happening, and read enough user comments on the Internet to see that others were having somewhat similar sound problems.

Enter the Cary CAD-120S II

Accordingly, I got far more proactive in contacting Billy Wright at Cary, and it became clear that the CAD-120S simply was not designed for general use. At the same time, however, Billy Wright also stated that “the CAD-120S was originally designed to match with a high-gain preamp. The input sensitivity is around 2.5–3.0 volts. The gain is around 10dB. In order to drive it to full output, the gain of the preamp would need to be around 20dB, such as that provided by the Cary SLP-98 preamplifier.

“The CAD-120S was also designed to operate as an 8-ohm amplifier. With a high gain preamp, I do not think there would be any issue with performance on 8-ohm or 4-ohm speakers. However, a modification to increase the sensitivity of the CAD-120S should eliminate any concerns with any of the preamps used in your testing.”

Not all that long afterward, I got the new version of the Cary CAD 120S, which Billy Wright said would be called the Cary CAD-120S II and which he described as follows: “The gain is increased to 28dB, and the sensitivity is 1.24V. We also made changes to the feedback network reducing overall global feedback.”

If you are a Cary SLP-98 preamp owner, these changes may not matter. If you are not, the modifications to the Cary CAD 120S that have made it into the CAD 120S II matter a lot. It is now fully compatible with any preamp I know of, and the sound is truly exceptional.

The Illusion of Live Music

As might be expected, both the Cary SLP-03 preamp and the Cary CAD-120SII are “voiced” to have the same sound characteristics and nuances. These sound characteristics are different enough from many other tube preamplifiers and amplifiers, and most sold-state preamps and amplifiers, to be an important option in a field where components increasingly stress apparent detail over musical realism, and in a world where far too many recordings seek the same emphasis on detail in ways that can make the end result too bright and hard.

I should make my listening biases clear here. I listen almost exclusively to acoustic music, much of it classical chamber music where any tilt in timbre can make the upper strings, woodwinds, brass, piano, and harpsichord sound slight unpleasant. The same is true of close-miked female voice and, much more rarely, a tenor pushing towards the limits of his register. I am only interested in musical detail to the extent that I hear it in live performances and that it does not interfere with a natural balance of the midrange and upper octaves. I am also particularly irritated when bright upper octaves seem to interact with the limits of the equipment used in making the recording, and harden peaks and transients. I am not interested in listening to technical accuracy; I am interested in listening to a close to the illusion of live acoustic music as possible.

Far too often, the high end seems to have moved in the opposite direction in recent years. This may well work with electronic and synthesized music where upper midrange peaks seem far less common, and most acoustic jazz and orchestral music does not highlight these problems to the same degree as recordings of chamber music and soloists do. Nevertheless, the search for technically flat frequency response and maximum detail has combined with recording problems to create the paradox that some recordings sound better in a mid-fi or home-theater system than a high-end system balanced for maximum upper-octave energy. There are reasons why some skeptics of the high end can say that “it sounds better on my car radio.”

In contrast, both the Cary SLP-03 preamp and the Cary CAD-120SII produce a sound that emphasizes the natural warmth of the midrange and upper bass, and that produces musically natural upper-octave energy without losing the highs you hear in live music. They also both set a soundstage that slightly emphasizes depth over width in comparison to many other preamps and amplifiers—when the music permits. Detail is natural, centerfill is excellent, and imaging is as about as realistic in size and as stable as the recording and the rest of your system and set up permit. Applause is more realistic, and sounds like the rustling of scores do not alter to emphasize the higher frequencies. Flute, clarinet, and piano have transients and peaks that sound musically realistic; the brass has bite without being hard, and female voice does not lose its warmth or emphasize sibilants and breathing sounds.

There is a cost to these advantages, although one that is slight compared to any system that overemphasizes or hardens the upper octaves. The sound characteristics of the Cary SLP-03 and CAD-120S II are less revealing with those older recordings that were miked at too great a distance or had softer highs in the first place. They are much more suited for speakers that emphasize flat, extended highs than those that effectively roll the highs or slightly depress the upper midrange. With truly neutral recordings, and with a properly balanced speaker and room setup, there are trade-offs in natural musical detail between the warmth of the Carys and top solid-state electronics like the Pass XP20 preamp and Pass XA160.5 amplifier I use as references.

As for the deep bass, the Cary CAD-120S II does very well, and its extra power can make a real difference in providing better dynamics and control than lower-powered tube amps. Nevertheless, even the best tube amplifier will have some limits in controlling the bass of most speakers compared to the best solid-state designs. It will also be somewhat more load dependent, although the Cary CAD-120S II is less sensitive to speaker loads than many other tube amps.

Incidentally, if you are wondering about the trade-off between the 120-watt ultralinear and 60-watt triode options, I preferred the 120-watt option most of the time. It was not as soft or sweet, but it sounded slightly more detailed and realistic with musical transients, and the bass and dynamics were consistently better. A bit like the choice between daylight and candlelight, much will depend on your mood.

No preamp and amp can do everything. No matter how you tailor your system, you have to give up something to get something. In fact, I found that with my front ends, and with the Quad 2909s and Vandersteen 5As in my listening room, the combination of the Cary SLP-03 preamp and the Cary CAD-120SII were a bit too warm, and got the best results with a combination of the Pass XP20 preamp and the Cary CAD-120SII.

This, however, highlights a point that we reviewers probably need to make more often. Even if you could disregard the recording and your front end, you would still be subject to the interactions of four components: the preamp, amp, speaker, and listening room. We are reviewing nuances and seeking an illusion in a world where system synergy involves far too many variable to predict what balance of timbre and detail will be most natural in any given setup—and “natural” is hard to apply even to acoustic music recorded in a hall or venue you know well. The range of components in making the recording is at least as subject to coloration and the range in playing it back. I can tell you that the Cary SLP-03 and Cary CAD-120S II are likely to be exceptionally musically real in any good setup in any good listening room, but finding the best synergy to create your illusion of choice is still going to be part of the chase in your hunt for the absolute sound.

SPECS & PRICING

CAD-120S II
Circuit type: Class AB, push-pull amplifier, ultralinear or triode mode operation with front panel selector switch
Gain: 28dB
Sensitivity: 1.24V
Power output: 120 watts per channel, ultralinear; 60 watts per channel, triode
Inputs: XLR balanced or RCA single-ended
Noise: -80dB
Input impedance: 100k ohm both RCA and balanced
Frequency response: 17Hz–25kHz @ 1 watt
Tube complement: Two 6SN7 input gain stage; two 6SN7 driver; eight KT88 output
Weight: 65 lbs.
Dimensions: 17” x 8” x 14”
Price: $5500

SLP-03
Preamplifier inputs: One pair balanced XLR connections, six pair single-ended RCA connections
Preamplifier outputs: One pair balanced XLR, two pair RCA
Tube complement: Four 12AU7 dual triode
Input impedance:100k ohm on RCA, 200k ohm on XLR
Output impedance: 500 ohm on XLR, 500 ohm on RCA
Rated output: RCA1V (8 volts maximum); XLR 2V (16 volts maximum)
Weight: 25 lbs
Dimensions: 17” x 4.5" x 13”
Price: $3000

CARY AUDIO DESIGN
1020 Goodworth Drive
Apex, NC 27539
(919) 355-0010
caryaudio.com