Luxman MQ‑300 Vacuum Tube Stereo Power Amplifier

Classic 300B Tube Power with Pure Musicality

The Luxman MQ‑300 is a masterfully engineered vacuum tube stereo power amplifier that brings the legendary warmth, harmonic richness, and expressive dynamics of 300B single‑ended triode design to modern high‑end audio systems. Inspired by Luxman’s iconic MB‑300 of the 1980s and updated with contemporary components and build quality, the MQ‑300 celebrates pure‑tube amplification philosophy — with zero global feedback, cathode bias circuitry, and a beautifully balanced signal path that puts musical emotion first.

Ideal for experienced audiophiles and lovers of single‑ended tube sound, the MQ‑300 pours immersive tonal colour and effortless flow into every performance. Its elegant industrial design and premium vacuum tube complement make it a superb centrepiece for refined two‑channel systems.

Key Features & Benefits

Authentic 300B Single‑Ended Output

Harnessing the beloved Takatsuki TA‑300B direct‑heated triodes in a single‑ended topology, the MQ‑300 delivers the classic tube sound audiophiles adore — warm, organic, and deeply musical — with 8 W + 8 W of output across multiple speaker loads.

Zero Feedback & Cathode Bias Circuit

Luxman’s thoughtful circuit design prioritises musical purity over measured power, using a non‑feedback cathode bias output stage and parallel two‑stage driver amplification to maintain tonal integrity and natural dynamics.

Premium Tube Complement

Featuring high‑quality vacuum tubes — including 5AR4 rectifiers, 6SN7GTB driver tubes, and the revered TA‑300B output tubes — the MQ‑300 provides not just performance but timbral nuance and authenticity.

Refined Frequency Performance

With a wide‑range frequency response from 20 Hz to 30 kHz, the MQ‑300 balances bass weight and treble clarity, giving you full‑spectrum musical reproduction.

High Signal‑to‑Noise Ratio

A respectable 105 dB (IHF‑A) S/N ratio ensures clean backgrounds and quiet listening, letting subtle musical details emerge.

Who It’s For

• Audiophiles and tube purists who value musical texture over brute power
• High‑sensitivity speaker systems that pair well with lower‑wattage tube amplifiers
• Listeners who appreciate timbral nuance and emotional engagement in analogue playback

Sound & Performance

Despite its modest wattage on paper, the MQ‑300’s 300B single‑ended design produces exceptionally rich harmonics and spatial depth, especially with efficient loudspeakers. Its non‑feedback topology and premium tubes work together to yield a smooth midrange, organic tonal balance, and engaging musical character — hallmarks of classic triode performance.

Design history

The design of the MQ-300 is a culmination of high performance parts, cutting edge technology and vacuum tube amplifier design ‘know how’ accumulated over many years. The MQ-300 is based on the cosmetic design and circuit configuration of the MB-300, the renowned masterpiece vacuum tube monaural power amplifier released in 1984. The elements of traditional design and elegant tonal quality that is unique to the performance of the TA-300B, a direct heated triode, have been maximised in the MQ-300. The MQ-300 exudes the quality of classic design from engraved nameplates bearing the company logos inlaid on the top of the metal coated transformer case and the luxurious piano finish natural walnut frame and other exterior parts. The MQ-300 represents the flagship model of vacuum tube amplifiers in which LUXMAN experience and cutting edge expertise come together to create a fitting model to celebrate the 90th anniversary of the foundation of the company.

300B single circuit configuration

The MQ-300 is a stereo power amplifier with a single configuration 8W + 8W output. The highly reliable TA-300B (manufactured by Takatsuki Electric Industry Co., Ltd) is used as the output tube for the MQ-300 and is the only output tube that is made in Japan. The configuration of the driver section is 6SN7GTB (manufactured by TungSol) two-stage parallel connection and the output section is the direct heated triode TA-300B non-feedback single power stage connection. This results in a natural and attractive tonal quality with rich musicality that is characteristic of the TA-300B. A cathod-bias type is used for the output stage which has less change in characteristics due to heat or voltage fluctuation. The DC-ignition method for heaters that suppresses hum generation is used for the 6SN7GTB and TA-300B ensuring sound quality and durability.

Large capacity output transformer

The orient cut-core large capacity output transformer with aligned magnetic fields as part of the output section supplies stable energy to the whole audio band even at the maximum power level. The logo nameplates inlaid on the top of the casings and the structure that is reminiscent of the classic OY type transformer produce a design with impact.

Output tube socket with floating structure

The output tube socket section with decorative rings has a floating support structure made of PORON which has excellent vibration damping and heat resistance to control microphonic noise. For lug terminals for wiring, large-sized steatite parts are used to provide outstanding insulation, heat resistance and durability.

Independent right and left power supply circuits

FINEMET* core material featuring low magnetic core loss and low magnetic distortion is used for the choke coil to achieve the expansive and natural sound quality. Complete independence of the right and left of the rectifying tube that includes the secondary winding of the power supply transformer, choke coil and block capacitor achieve high level separate performance.

*FINEMET is a registered trademark of Hitachi Metals, Ltd.

High rigidity aluminium chassis

For vacuum tubes design where electrons fly about, external vibration and resonance can be great enemies that can interfere with sound signal transmission. The MQ-300 combats this with a high rigidity chassis structure that combines a 1.6mm thick steel chassis, 2mm thick bottom board and a 12mm thick top panel to block such vibrations.

Rectifying tube and voltage amplifier tube

The Sovtek indirectly heated tube, the 5AR4 is selected as the rectifying tube, featuring low internal impedance and excellent regulation resulting in the gentle start-up of the power supply and thereby prolonging the life of the vacuum tube. A highly reliable TUNG-SOL 6SN7GTB that can withstand a high voltage load is used for the voltage amplifier tube.

High grade large size terminals

The MQ-300 is equipped with 4/8/16 Ω independent. 16 Ω dedicated terminals are suitable for connecting vintage speakers. Copper alloy input terminals, that combine the conductivity of copper and the hardness of brass, as well as gradation cast iron legs suppress any external vibrations.

Coupling capacitor and cathode resistance

LUXMAN’s proprietary oil capacitors are used as coupling capacitors for connecting circuits resulting in smooth sound quality. Dale non-inductive metal clad resistors are used for the cathode resistances on the output stage to avoid inductive components that may have a harmful effect on transmission signals.