Technics SH-9010 Stereo Universal Frequency Equalizer
Five bands per channel, each one with a center frequency you can move - a graphic EQ that thinks like a parametric, for under $450.
Overview
Here's the pitch that ran in Audio, High Fidelity, DB Magazine, and Recording Engineer around October 1977. A stereo equalizer with the slide controls of a graphic, but the sweepable center frequencies and adjustable bandwidth of a parametric, priced "under $450." Technics called the SH-9010 a "stereo universal frequency equalizer," and period advertising described it as a radical departure in circuit principles that combined the flexibility of both a graphic and a parametric equalizer (Audio, October 1977, p.49).
A normal five-band graphic gives you five fixed hinges on the spectrum. The SH-9010 gives you five hinges you can slide around (Audio, October 1977, p.49).
The five bands per channel carry nominal center frequencies of 60 Hz, 240 Hz, 1 kHz, 4 kHz, and 16 kHz. Each one is variable by as much as ±1.6 octaves with a control knob beneath its slide pot. The 60 Hz band reportedly sweeps from 20 Hz up to 180 Hz, the 240 Hz band from 80 Hz to 720 Hz, the 1 kHz band from 333 Hz to 3 kHz, the 4 kHz band from 1.3 kHz to 12 kHz, and the 16 kHz band from 5.3 kHz up to 48 kHz. That last range is the odd one. A band that reaches 48 kHz is working far above the audible range, which says something about how Technics designed the circuit's headroom and filter behavior.
The second trick is what separates the SH-9010 from a swept graphic. Bandwidth, the Q, is variable from 0.7 to 7.0. Narrow the Q and you can notch out a specific hum or resonance. Widen it and the same band balances a whole section of instruments. Technics' own copy says it plainly: broad or narrow, independently per band or several at once, "you can balance an entire string section or eliminate an annoying little hum."
The numbers behind the circuit are respectable for the price class. Total harmonic distortion is quoted at 0.02%. Frequency response is specified as 10 Hz to 20 kHz (+0, −0.2 dB) in the audio band, extending to 10 Hz - 70 kHz (+0, −3 dB). That wideband figure again points to a circuit built with more bandwidth than the audible range strictly requires. Signal-to-noise is 90 dB referenced to IHF-A weighting, and gain sits at 0 ±1 dB, so the unit is designed to pass signal at unity when the sliders are centered. Each band's level control spans +12 dB to −12 dB across five elements per channel.
The suggested retail price was $449.95. Technics was careful to note that this was a recommended figure and that actual retail would be set by dealers. The headline framing, "under $450," put a parametric-capable equalizer at a price that undercut what that feature set normally commanded.
On sourcing: period advertising positioned the SH-9010 as offering both graphic and parametric flexibility at a price under $450 (Audio, October 1977, p.49). It found its way into professional racks, not just home stereo cabinets. As with any vintage active electronics of this age, condition and service history matter more than the spec sheet, and a unit should be judged on how it actually operates.
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