Everyone knows Sansui for the silver-faced receivers. Almost nobody knows they spent the early sixties building tube gear, and the MX-10 is the good one: a six-input valve mixing preamp with five 12AX7s in the signal path, a 6X4 tube rectifier, and switchable transformer-coupled mic inputs. Three mic channels, a magnetic phono stage, a tape head input and an aux, all summed through a cathode follower output. It cost ¥28,100 new in 1960. It has outlived every solid-state Sansui built since.
FEATURES & PROS:
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Five 12AX7s and a 12AT7: the whole signal path is valve, and every tube in it is still made today.
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Tube rectification: a 6X4 in the power supply, so it sags under load the way plugins spend a lot of code pretending to.
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Transformer mic inputs: the detachable A-603 switches between 50kΩ and 600Ω. Real iron on the front end, which is the bit you actually hear.
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Cathode follower output: low impedance out, drives long cable runs without losing the top. Same idea as the Ampex and RCA broadcast preamps.
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Six inputs at once: three mics, magnetic phono, tape head and aux, mixed together.
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High-cut and low-cut filters, plus a VU meter: for working, not for decoration.
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DC amplification on the front end: a deliberate 1960 choice to keep the noise floor down, and it worked.
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444mm wide: a whisker under nineteen inches, so it panels into a rack without a fight.
WHAT YOU WOULD ACTUALLY USE IT FOR: Three channels of transformer-coupled valve gain on drum overheads, a room mic or a guitar cab. A summing and saturation box when a mix sounds too much like a computer. Or a valve phono stage with a VU meter, which is a different sale entirely.
SPECIFICATIONS
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Model: Sansui MX-10 audio mixing pre-amplifier
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Released: circa 1960
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Original price: ¥28,100
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Tubes: 5 x 12AX7, 1 x 12AT7, 1 x 6X4 rectifier
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Inputs: 3 x microphone (50kΩ / 600Ω switchable via detachable A-603 transformer), magnetic phono, tape head, aux
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Output: cathode follower, low impedance
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Frequency response: 30Hz to 15kHz within 1.5dB, 20Hz to 20kHz within 3dB
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Distortion: under 1% at 1V out (mic)
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Filters: high-cut and low-cut
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Metering: VU
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Dimensions: 444 x 144 x 195mm
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Weight: 6.4kg
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Format: tabletop, rack-mountable
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Condition: used, powers on, not yet fully bench-tested. This is a sixty-five year old valve unit, so assume it wants a recap before serious work. We will tell you exactly what we find before it ships.
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Voltage: Japanese-market unit. Confirm with us before ordering, as some export examples are switchable 110-120 / 210-220V and some are not.
Further reading: Two EQ Knobs and a Fader: How the Golden Age of Highlife Was Actually Recorded
