Counterpoint SA-3000 Preamplifier Review

The Counterpoint SA-3000 is a hybrid preamplifier combining solid-state and vacuum-tube circuitry. Its power transformer is a separate unit that’s always active when plugged into a live electrical outlet. In the preamplifier’s standby mode (equivalent to the off setting of a conventional amplifier), the tube heaters are lit from a 6-volt DC supply and all solid-state circuits are energized from their ± 6-volt and ± 15-volt supplies. Switching from standby to ready turns on the heater voltage of the 6CA4 rectifier, and the 240-volt power supply energizes the vacuum-tube stages.

Although no schematic diagram of the SA-3000's circuits is provided in its comprehensive manual, a technical description of its circuit layout indicates that, in general, each stage consists of one or more FET’s (field-effect transistors) and a triode (one-half of a 6DJ8 tube).

Buffer stages are used between each triode stage and the following load to isolate the amplifier sections from low-impedance circuits that could affect their frequency response or distortion characteristics. Counterpoint says that the SA-3000’s active stages were designed to reduce normal measurable distortion levels by at least one order of magnitude without using feedback to “preserve the desirable sound quality of vacuum tubes.” Most of the SA-3000’s performance specifications are typical of today’s high-quality preamplifiers. The line-level inputs have an impedance of 20,000 ohms (unselected outputs are shunted with 100 ohms to minimize noise pickup and crosstalk from unused inputs), and the phono inputs have a 47,000-ohm impedance The moving-coil (mc) load resistance can be reduced as desired by inserting appropriate shunt resistors into clips on the circuit board. The rated maximum level of the line-output stage is 24 volts peak to peak (8.5 volts RMS) with 1 percent distortion from 20 to 20,000 Hz. The power-supply regulator has so much reserve control range that the preamplifier is rated for operation from power sources of 88 to 133 volts at 50 or 60 Hz. Its standby power consumption is 35 watts, increasing to 50 watts in the operating mode.

The SA-3000 is a handsome component. It has a satin-silver front panel and side plates, with rounded front edges and corners, and a black top. Like most “high-end” preamplifiers, the SA-3000 has no tone controls or filters. A large knob at the left of the panel selects the input (phono, CD, tuner, video, Tape 2, or aux); a similar knob at the right end is the volume control. A rotary monitor switch selects either the source or Tape 1 playback signal for listening, and nearby is a center-detented balance control. A miniature toggle switch selects mono or stereo mode, and two other switches serve as ready/standby and operate/mute selectors.

The preamplifier’s operating status is indicated by a colored led at the top center of the panel. In stand-by mode it glows red. When the switch is moved to ready, the light turns yellow and blinks on and off for about 60 seconds while the circuits stabilize. It then remains on steadily, in yellow if mute is selected, green otherwise.

All the signal jacks on the rear apron are gold-plated. There are two pairs of main output jacks (for driving two amplifiers) and two sets of tape-recording outputs. Although the SA-3000 has separate inputs for mm and MC phono cartridges, the single phono-preamplifier section must be set for one type or the other with internal switches after removing the top cover (held in place by seventeen screws). Shorting plugs are inserted in the unused phono-input jacks.

The Counterpoint SA-3000 measures 19 inches wide, 12-5/8 inches deep, and 4-1/2 inches high, and it weighs 22 pounds. Price: $1,895.

Lab Tests

The Counterpoint SA-3000 had an input sensitivity, for a 0.5-volt output, of 31.5 millivolts (mV) through a high-level input and 1.7 mV through the mm phono input. The respective A-weighted noise levels were —87.5 and —73.2 dB, referred to 0.5 volt. The phono stage overloaded at 300 mV at 1 000 Hz and 125 mV at 20 Hz. At 20,000 Hz the overload level was a rather low 42 mV, at which point the waveform collapsed and varied erratically for a couple of seconds. Although the output eventually stabilized and did not show waveform distortion until a much higher level was reached, we consider the first obvious departure from linearity to be the actual overload point. The phono-input impedance was 47,000 ohms in parallel with a very low 25-picofarad (pF) capacitance.

The output clipped at about 8 volts rms. Total harmonic distortion (THD) was only 0.003 percent at 0.5 volt output, increasing to 0.008 percent at I volt and 0.025 percent at 3 volts. Frequency response through a line input (CD) was ±0.05 dB from 10 to 20,000 Hz, falling to — 0.2 dB at 50,000 Hz. The RIAA phono-equalizalion error was ±0.2 dB from 10 to 20,000 Hz.

Phase shift from input to output varied between +2.5 and —5.5 degrees from 20 to 20.000 Hz, and there was a polarity reversal from the CD input to the main output (contrary to the implication of the specifications in the manual). A spectrum analysis of the preamplifier’s noise output showed readings in the range of 3 to 15 microvolts between 75 and 20,000 Hz, corresponding to —104 to —90 dB referred to 0.5 volt. At 60 Hz there was a 60-microvolt hum component ( — 78 dB relative to 0.5 volt).

Comments

The quality of the Counterpoint SA-3000’s construction was apparent at first glance—an impression that was reinforced when we handled the controls and removed the top cover to examine its interior. (Every owner will get the same opportunity, since it is necessary to remove the cover to install the tubes and to set the phono preamplifier for the preferred cartridge type.) All of the controls operated with silky smoothness and a positive feel Top-quality parts are used (ceramic-wafer rotary switches for input selection, for example), and the single large circuit board is a thing of beauty, with virtually no visible wiring. The absence of the usual jungle of cables and wires snaking about the interior was striking.

Actually, this kind of construction is what one should expect from any product priced in the range of the SA-3000 (which is roughly in the middle of the Counterpoint line). We cannot judge a component’s reliability during the brief period of a test program, but we would expect this preamplifier to be as rugged and lasting as a consumer electronic product can be.

The operation of the SA-3000 fit the same pattern of quality. There were no turn-on, turn-off or switching transients and, for all practical purposes, no crosstalk.

What about sound? Well, I make no secret of the fact that (to me) all good preamplifiers sound pretty much alike. In an A/B comparison with a good but much less expensive preamplifier, playing the same CD with matched levels. I heard no difference. That came as no surprise to me, nor should it to any reader. There is more to appreciating fine audio components than what impinges on the eardrums. I have no doubt that anyone who invests in the SA-3000 and pairs it with a good power amplifier and good speakers will not be disappointed. It fairly oozes a sense of quality, and nothing about its sound or feel conflicts with that impression. It is a component I would be proud to own.

Read all

Counterpoint reviews

Read all