Luxman SQ77 (1964)
The Luxman SQ77 is a tube-type pre-main (integrated) amplifier released in April 1964 at ¥27,800. It's compact: 348mm wide, 130mm high, 215mm deep, and 8.7kg. The output stage is push-pull 6BQ5 (EL84) with a high-fidelity output transformer using a dedicated NF coil. The tube complement runs nine total: four 6BQ5s for the output and seven 12AX7s in the preamp and driver stages. Silicon rectification (four SM-150b diodes) helped keep the chassis small for its era.
Early production units were rated at 10W+10W (55 Hz, 1% or less distortion) with a frequency response of 20 Hz to 25 kHz (-2dB). Later production circa 1965 raised output to 12W+12W, with a revised response spec of 20 Hz to 20 kHz ±1dB. Input sensitivity also shifted slightly between runs. Phono and tape stayed at 4mV, while the two aux inputs went from 280mV to 300mV. Tone control is a left/right independent NF-type circuit offering ±9dB at 100 Hz (bass) and ±9 dB at 10 kHz (treble). The front panel also carries a tape monitor, an 80 Hz rumble filter, a 5 kHz scratch filter, and a headphone jack. The panel design appears to have changed between the early and later production runs.
Beyond its listing in period equipment directories, almost nothing is recorded about the SQ77's market position or reception. The naming gets confusing from here. Sources reference later "SQ77T" and "SQ77T/II" variants, and one French forum claims the SQ77T/II "succeeds the first SQ77" and is "the same but with tubes." That reads oddly, since the base SQ77 is itself fully tube-based. Another archive dates an SQ-77T to 1975 and calls it solid-state, while StereoNET lists the SQ77T/II as circa 1968 and mentions "Germanium valve/transistor." None of these sources explicitly confirm the relationship between the designations, and the base model's facts above come from a single spec page with no independent corroboration. A service manual exists for the SQ77TII variant, but its contents weren't accessible for this research.
Known specifications for the base SQ77 (1964):
- Output: 10W+10W (early) / 12W+12W (later), 55 Hz, 1% or less THD
- Frequency response: 20 Hz–25 kHz −2dB (early) / 20 Hz–20 kHz ±1dB (later)
- Input sensitivity: Phono 4mV / Tape 4mV / Aux 280mV (early) or 300mV (later)
- S/N ratio: Phono 57dB / Tape 55dB / Aux 63dB
- Tubes: 6BQ5 ×4, 12AX7 ×7
- Dimensions: 348 × 130 × 215 mm; 8.7 kg
- Price at launch: ¥27,800
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