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.