Luxman SQ 707 (1969)
A transistorized integrated amplifier introduced in 1969, built for entry-level audiophiles and using Luxman's own circuit engineering.
Overview
The Luxman SQ 707 is a solid-state integrated amplifier released in August 1969. Preamp and power amp share one chassis, and the aim was accessible high fidelity. It uses Luxman's "LAX" technology. It has independent left and right tone controls, a tape monitor function, and support for two sets of speakers. The layout is plain but functional. The front panel is aluminum with a hairline texture and white gold alumite dyeing, with matching knobs and a heat-resistant, leather-textured hood.
Specifications
| Continuous output | 20W/20W (4 Ω) |
| Continuous output | 17W/17W (8 Ω) |
| Total harmonic distortion | 1% or less (at maximum output) |
| Frequency response | 30 Hz to 30 kHz ± 1 dB or less |
| Input Sensitivity / Impedance Phono | 2mV / 50k Ω |
| Input Sensitivity / Impedance Tuner, Aux, Tape rec | 120mV / 50k Ω |
| Signal-to-noise ratio Phono | 60 dB or more |
| Signal-to-noise ratio Tuner, Aux, Tape rec | 65 dB or higher |
| Residual noise | 2 mV or less |
| Equalizer | RIAA |
| Tone control | NF type bending point switching system |
| Damping factor | Approximately 20 (8 Ω, 1 kHz) |
| Accessory circuits | Tape monitor, Attenuator (-18dB), Headphone jack, Mode switching (stereo - mono), Speaker switching (2 systems), Tone control curve point switching |
| Semiconductors used | Transistor Silicon varistor Silicon diode 2SD94 : 4, 2SC853 : 2, 2SA545 : 2, 2SC734 : 2, 2SC694G : 2, 2SC693GU : 8, SV-03 : 2, 1S1850 : 1 |
| Power consumption | 30W (no signal), 90W (at maximum output) |
| Dimensions | Width 373 x Height 125 x Depth 227 mm |
| Weight | 4.9kg |
Design
The SQ 707 uses a quasi-complementary service system circuit in the power amplifier section and features an SEPP-OTL (Single-Ended Push-Pull, Output Transformer-Less) output stage, with no protection circuit per Luxman's unique design. The preamp section employs an NF-type equalizer and NF-type tone control using selected low-noise transistors. It includes two sets of speaker terminals and uses a Luxman-original speaker terminal design. The internal layout is rationalized without a sub-chassis. The front panel has an aluminum hairline finish with white gold alumite dyeing, and the hood is made of heat-resistant high-impact styrol with a leather-like texture.
Market
The SQ 707 was originally priced at ¥35,000. An optional wooden case cost ¥3,500.
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