Pioneer SG-90 Graphic Equalizer – 17 Bands, Silver, Japan
$345.00
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Pioneer SG-90 — Seventeen Bands per Channel at 0.001% Distortion
A Japanese-built silver-faced two-thirds-octave equalizer with seventeen bands per channel — thirty-four sliders in total — and a specification sheet that belongs on considerably more expensive equipment.
Seventeen Bands per Channel
Most graphic equalizers give you seven or ten bands per channel, which is enough to shape a sound but not enough to fix a room. The SG-90 gives you seventeen, on two-thirds-octave centres running from 16 Hz to 25,000 Hz. That resolution is the difference between nudging “the bass” and actually addressing the specific 63 Hz peak your room produces because of where the walls are. Anyone who has fought a boomy corner or a hard-surfaced living room will understand immediately why this matters.
Measured Performance
The measured performance is what elevates it. Total harmonic distortion of 0.001% with controls flat, a signal-to-noise ratio of 120 dB, and frequency response from 10 Hz to 100,000 Hz. Those are figures you would expect from serious separates, not from a tone-shaping accessory, and they mean the SG-90 can sit permanently in your signal path without costing you anything when it is not being used. It was built in Japan, in the years when that still described the top of Pioneer’s manufacturing rather than the average of it.
Control Ranges
Two control ranges are provided. The plus or minus 12 dB setting is for normal corrective work; switching to plus or minus 6 dB halves the range across every slider so the same physical movement produces a finer adjustment. It is the difference between a coarse tool and a precise one, and it is exactly what you want once you are past the obvious problems and into the last few decibels.
Beyond Equalization
There is more here than equalization. An auto fader with display creates smooth fade-ins and fade-outs, which is a genuine luxury for anyone still making compilations. The equalizer character selector inverts the entire frequency curve, which allows the SG-90 to perform tape noise reduction by recording with one curve and playing back with its mirror image. Two tape decks can be connected with equalization applied during dubbing, and EQ switches let you equalize what you are listening to while recording the source unequalized. It is a piece built when tape was still how people kept music, and it takes that job seriously.
Connections
Connection is by standard RCA through a tape monitor loop, so it works with essentially any receiver or integrated amplifier that has tape terminals. It is also switchable between 120 and 220 volts.
Condition
Cosmetically graded Good, with honest wear consistent with its age and nothing affecting performance. Thoroughly inspected and tested in-house and working properly.
Seventeen bands per channel with distortion at one thousandth of a percent is a genuinely uncommon combination, and it makes the SG-90 one of the more capable equalizers of its era — a piece that can properly fix a difficult room rather than merely colour it.
Pioneer SG-90 Specifications
- Design: Stereo graphic equalizer, two-thirds octave
- Bands: 17 per channel, 34 total
- Centre frequencies: 16, 25, 40, 63, 100, 160, 250, 400, 630, 1k, 1.6k, 2.5k, 4k, 6.3k, 10k, 16k, 25kHz
- Control range: +/-12dB / +/-6dB, switchable
- Total harmonic distortion: 0.001% (20Hz-20kHz, controls flat)
- Signal to noise ratio: 120dB
- Frequency response: 10Hz-100,000Hz
- Output level: 1V
- Gain: 0dB, controls flat
- Features: Auto fader with display, equalizer character selector (reverse response), two-deck dubbing with EQ, Tape 1 / Tape 2 / Source selection
- Power: 120V / 220V switchable
- Finish: Silver
- Year of introduction: 1983
- Original manufacturer: Pioneer – Made in Japan
- Dimensions: (Width x Height x Depth) 16.54 x 5.16 x 13.82 inches (420 x 131 x 351 mm)
- Weight: 15.9 lbs (7.2 kg)
✅ Good News for International Buyers
This unit is switchable between 120V and 220V, so it can be set to suit most markets worldwide. No step-down transformer is required — only an appropriate plug adapter.
✅ Buy With Confidence — The Radique Promise
Backed by Radique Audio’s Bumper-to-Bumper Warranty and our Perpetual Trade-Back Program. When you’re ready to move on, we’ll take it back. That’s the Radique difference.
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| Weight | 18 lbs |
|---|---|
| Dimensions | 17.82 × 20.54 × 9.16 in |
| Mains Voltage | Selectable / Universal Voltage |
Pioneer began in Tokyo in January 1938, when Nozomu Matsumoto set up shop around the A-8 speaker he had built the year before. By the late 1970s its SX receivers were at the heart of the hi-fi power race. We carry Pioneer stereo receivers and AV receivers, CD players, cassette decks, tuners and equalizers. We've had more than 240 Pioneer listings so far, covering 140 different models. Every used Pioneer here is inspected, tested and serviced as required, then photographed in-house and covered by our Bumper-to-Bumper Warranty and Perpetual Trade-Back Program. Don't see the model you want? Tell us on First Dibs and we'll email you when one arrives.
Pioneer is one of our two top-selling brands of vintage amps and receivers, along with Marantz. Our five best-selling Pioneer models so far: the SX-650, SX-750, SX-580, SX-780 and SX-680, all vintage stereo receivers from the 1976 and 1978 SX families. We also offer our custom cherry cabinets for these vintage Pioneers, hand-made from all-natural Ottawa Valley cherry, and we've upgraded dozens of Pioneers with them so far.
The Pioneer story, 1938 to today
Nozomu Matsumoto developed the A-8 speaker in 1937, and in January 1938 he set up Fukuin Shokai Denki Seisakusho in Tokyo. "Pioneer" was first the name of that speaker. Some histories give 1936 in Osaka as the start, but Pioneer dates itself to January 1938 in Tokyo. The company was incorporated in 1947 and renamed Pioneer Electronic Corporation in 1961.
Stereo and the US. In 1962 Pioneer introduced the PSC-5A, which it calls the first stereo with separate speaker cabinets, and its first PL turntables. Pioneer Electronics U.S.A. was founded in New York in 1966.
The power race. After a 1974 US Federal Trade Commission rule tightened how amplifier power was rated, receiver makers competed on watts. Pioneer's SX-1250 of 1976 was rated at 160 watts per channel, and the SX-1980 of 1978 to 1980 at 270.
CD and Elite. The P-D1 of 1982 was Pioneer's first CD player, and Elite-branded components were on sale by 1985.
Today. Pioneer sold its home audio business to Onkyo in 2015, keeping its car and DJ businesses, and Pioneer-branded home theatre gear was later made under licence. In December 2025 CarUX, part of Taiwan's Innolux, completed its purchase of Pioneer Corporation, which now focuses on in-car products.
Which Pioneer is which?
Early-1970s SX receivers: models such as the SX-424 to SX-828, rated at about 15 to 50 watts per channel.
The 1976 "x50" SX receivers: from the SX-450 at 15 watts per channel up to the SX-1250 at 160. Our best-selling SX-650 and SX-750 come from this family.
The 1978 "x80" SX receivers: including the SX-580, SX-680 and SX-780 we sell most, up to the SX-1980 flagship with quartz-lock tuning, which weighs more than 35 kg.
Spec and Exclusive separates: higher-end amplifiers such as the Spec-1 preamplifier (1976 to 1980) and the Exclusive C3/M3 pair (1974).
Elite: Pioneer's upper line from the mid-1980s, for example the PD-9010X CD player.
PL turntables, CT cassette decks and CD players: PL turntables from 1962, such as the PL-12 and the linear-tracking PL-L1; CT decks such as the three-head CT-F1000; and CD players from the 1982 P-D1 to magazine-loading changers such as the PD-M6.
Buying used Pioneer: what to check
Controls and switches. Crackle when you turn a control or work a switch usually means dirt, and restorers clean every pot and switch.
Capacitors. Electrolytic capacitors in 1970s receivers are often past their best, and full restorations replace them.
Big SX models. Owners and restorers report heat stress on the power-supply board of large receivers such as the SX-1250. Ask what has been done.
Relay, lamps and bias. The protection relay is a common replacement, dial lamps burn out and are often converted to LED, and restorers set the bias and DC offset.
Cassette decks. Check the heads, fast-forward and rewind, Dolby and every button. Belts age even when the deck looks perfect.
Everything we list is inspected, tested and serviced as required here, and comes with our warranty.
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