A Neat, Sweet, Simple Preamp
Technics Model SU-001 stereo preamplifier, in metal case.
Dimensions: 11 3/4 by 2 inches (front panel), 8 1/4 inches deep plus clearance for controls and connections. AC convenience outlets: 1 unswitched (300 watts max.), 3 unswitched (total 250 watts max.). Price: $260. Warranty: "limited," two years parts and labor. Manufacturer: Matsushita Electric Co., Japan; U.S. distributor: Panasonic Co., Div. of Matsushita Electric Corp. of America, 1 Panasonic Way, Secaucus, N.J. 07094.
If you have any doubts about whether the so-called micro format is intended to consist of "real" components, setting up the SU-001 should dispel them. It is finely detailed in a way that instills confidence. The back-panel contacts are gold plated, as are those on the short stereo interconnect cables that are supplied with the preamp. One is a special tuner-to-preamp-to-power-amp affair-it might almost be called a harness-that makes interconnection of an all-Technics-micro system ultraneat. Even the feet on the bottom have a special detail: a little folddown element at the front of the case to tilt the unit for better faceplate visibility. (We had no complaints about the visibility, and when the micros are stacked as Technics suggests in its multiple systems-stacking diagrams, the feature is not needed.) The size of the front panel in no way inhibits its human engineering; the controls are, if anything, easier to use than those in many full-size receivers. The detented tone controls and other knobs display their settings with exemplary clarity; the tape-monitor button (alas, for only one deck) is twice the size of many; the filter and loudness buttons are adequate for all but the ultra-myopic.
---------------------
Technics Model SU-001 Preamplifier
Frequency response
Input characteristics (re 0. moving-coil phono fixed-coil phono aux, tuner, tape
+0,-'/. dB, <10 Hz to 37.3 kHz
+0,-3 dB, <10 Hz to 170 kHz 5 V; noise A-weighted)
Sensitivity 54 pV 1.2 mV 78 mV
S/N ratio 82 dB 88'/ dB 90 dB
RIAA equalization (either phono mode) ±'A. dB, 20 Hz to 20 kHz
Phono overload (clipping) moving coil fixed coil (moving magnet, etc.)
Phono input impedance moving coil fixed coil 8.2 mV at 1 kHz 215 mV at 1 kHz 47 ohms 47K ohms; 135 pF
Output clipping level 8.8 V
Harmonic distortion (THD) <0.01%
High filter -3 dB at 8.6 kHz; 6 dB per octave
Subsonic filter -3 dB at 35 Hz; 12 dB per octave
---------------------
There even is provision on the selector for moving-coil cartridges via a head-amp stage that inserts into the phono-input circuitry. (There are no separate moving-coil input jacks.) The phono circuitry is quite flat in both modes, and the DSL data show it to be excellently engineered for minimum noise consistent with the generous overload points.
The loudness feature follows the most recent perception research in addressing the bass only. Some listeners (including some of ours) miss the extra "zing" that the more conventional approach introduces at low listening levels, but we generally agree that the sound is more natural without it. The tone controls shelve, rather than peak: good for altering inter-range balances, though less effective if you want to compensate, for example, for a speaker that sounds either boomy or bodiless in the deep bass. The range of both is limited to ± 10 dB maximum-less than average but entirely adequate, in our opinion. The high filter, which reduces 15-kHz output by only about 6 dB, doesn't strike us as particularly effective; while the subsonic filter is much better, its turnover frequency may seem a hair high for those who like organ pedal passages.
Overall performance and behavior are very good indeed.
Distortion is essentially nonexistent, even through the phono stage, which exhibits a "classic" impedance of fairly low capacitance, allowing precise tailoring to the requirements of your fixed-coil pickup. (The so-called MM phono stage is, of course, equally appropriate for moving-iron and some high-output moving-coil designs as well.) The lab found all other input and output connections well suited for hookup to any typical modern equipment.
And the preamp listens well. It is quiet, clean, unobtrusive.
While there really is no reason why a preamp should not be small-indeed many "full size" ones are no bigger than this micro-we found the elegant compactness of the Technics especially pleasurable to work with. Aside from the concerns of the ardent tape-o-phile or the inveterate user of outboard signal processors, who will find the connection options (and perhaps the features, since there is not even a stereo/mono switch) less than adequate, we see no reason why this design or its like should not find a respected place among conventional components, let alone among the micros that it so neatly exemplifies.
Also see:
Technics Model SE-C001 stereo/mono power amplifier (review, Jun. 1979)