Luxman SQ-708 (1979)
The Luxman SQ-708 is a solid-state preamplifier that Luxman introduced in 1979. It belongs to the SQ series from the late 1970s and early 1980s. It is not as well documented as some of its contemporaries, but it has a following among vintage audio collectors.
Design and Build Quality
The SQ-708 has a minimalist front panel, typical of Luxman at the time - clean lines, a brushed aluminum finish and few controls. The chassis is heavy-gauge steel with internal damping to reduce vibration and electromagnetic interference. That mechanical stability contributes to a low noise floor and high signal clarity.
The unit measures approximately 430 mm (W) × 140 mm (H) × 360 mm (D) and weighs around 8.5 kg. The rear panel has gold-plated RCA jacks for line-level inputs and outputs, which resist corrosion. There are four line-level inputs (labeled Phono, Tuner, Tape, and Aux), one tape output, and a dedicated preamp output for connecting a power amplifier.
The volume control is a dual-mono passive circuit that uses precision stepped attenuators instead of a traditional potentiometer. This minimizes channel crosstalk and gives precise, repeatable volume settings. The stepped attenuator also avoids the channel imbalance and scratchiness that can plague aging potentiometers, so the SQ-708 should hold up well over the long term.
Phono Stage and Input Options
The SQ-708 has a built-in phono preamplifier for moving magnet (MM) cartridges. The phono stage follows the RIAA equalization curve and provides approximately 40 dB of gain, which is standard for MM. Input sensitivity is around 5 mV, with an input impedance of 47 kΩ and 100 pF capacitance. That suits most vintage and modern MM cartridges.
Luxman did not include a moving coil (MC) input on this model. The MM stage is highly regarded for its low noise and natural tonal balance. Anyone who wants MC compatibility typically pairs the SQ-708 with an external step-up transformer or MC preamp.
The line inputs have an input sensitivity of 150 mV and a maximum input level of 2 V. The output level is rated at 2 V RMS, enough to drive virtually any power amplifier of the era. Frequency response for the line stage is 10 Hz to 100 kHz (+0, -1 dB), far beyond the audible range.
Circuitry and Sound Characteristics
The SQ-708 is a fully discrete solid-state design with no integrated circuits (ICs) in the signal path. Luxman used discrete transistors and premium capacitors throughout the audio path. The buffer and gain stages use its proprietary “Discrete OP Amp” configuration, which provides high slew rate, low distortion, and excellent transient response.
Total harmonic distortion (THD) is rated at less than 0.05% across the audible spectrum, and the signal-to-noise ratio exceeds 90 dB, measured at rated output. Those numbers compete favorably with offerings from Accuphase, Sansui, and Yamaha’s high-end CA series.
The SQ-708 is known for a warm midrange, smooth treble, and tight, controlled bass. It presents vocal and acoustic recordings naturally, and listeners who value musicality over clinical accuracy favor it. It is solid-state, but it has a tube-like liquidity that many attribute to Luxman’s component selection and circuit topology.
Features and User Experience
The front panel has a large central volume knob, a source selector knob, and basic function switches: Mono, Mute, and Tape Monitor. The Mono switch is there for older recordings and AM radio. The Tape Monitor lets you listen to tape inputs independently. The Mute function is useful for eliminating turn-on thumps when switching sources.
A blue pilot light illuminates the Luxman logo when the unit is powered on. The switches and knobs have a solid mechanical feel.
The SQ-708 operates on 100V AC (Japan standard), but versions modified for 120V or 230V operation exist in international markets. Users outside Japan should verify voltage compatibility before use, since internal transformer replacement may be required.
Position in Luxman’s Lineage
The SQ-708 sits in the upper mid-tier of Luxman’s preamplifier lineup from the late 1970s. It shares design ideas with higher-end models like the SQ-07 and SQ-507, particularly discrete circuitry and stepped attenuators. It lacks some features those models have, such as balanced outputs or remote volume control.
It was priced as a premium product but not as an ultra-luxury item, which made it attainable for serious audiophiles of the time.
Legacy and Collectibility
Today the SQ-708 is sought after by collectors and vintage audio enthusiasts. Its reputation for reliability is strong, assuming proper maintenance, and many units still function perfectly decades later. Capacitor aging is the most common issue, and a full recapping by a qualified technician can restore the preamplifier to like-new performance.
On the secondary market, the SQ-708 typically sells between $400 and $800 USD, depending on condition, originality, and included accessories. Fully operational units with minimal wear command higher prices, especially when paired with other Luxman components.
Conclusion
The SQ-708 was released during a golden era of analog audio. It is overshadowed by more famous models from Luxman and its competitors.
Its discrete circuitry, stepped attenuator, and warm sonic character are the main reasons to look for one. The SQ-708 is still respected more than four decades after its introduction.
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