MARK LEVINSON NO.431

Second-hand. In excellent conditions. No visible signs of wear. Comes with original packaging and manual.

The Mark Levinson No.431 is a compact and refined stereo power amplifier that upholds the brand’s reputation for exceptional build quality and sonic performance. Compared to the earlier No.334, the No.431 is shorter, slightly wider and deeper, and significantly lighter, yet it delivers nearly double the power into both 8 and 4 ohm loads while occupying less space.

In terms of thermal management, the amplifier forgoes the prominent external heatsinks of the No.334 and the cooling fans of the No.436, opting instead for a more efficient internal solution. The heatsinks are mounted inside side tunnels with vents and perforations that promote a natural chimney effect. This convection airflow is sufficient to keep operating temperatures low without the need for fans, preventing dust accumulation and ensuring silent operation. The amplifier runs at reduced bias, which contributes to its lower heat output and suitability for domestic environments.

Control elements are split between the front and rear panels. In addition to the Power and Standby buttons, the rear hosts a Power Save switch allowing four operating modes: Off, On, Sleep, and Standby. Sleep mode reduces power consumption to under 15 watts, keeping only the control and communication circuits active—ideal for complex setups where a central system can manage amplifier status via a DC trigger. Remote control is also possible via a mini-jack input for external infrared sensors.

The rear panel features high-quality connectors: proprietary speaker binding posts, balanced XLR and unbalanced RCA inputs, an IEC inlet for a detachable power cable, and several control ports. These include an RJ-11 for RS-232 compatibility with Crestron or AMX systems and RJ-45 Link ports for integration with other Mark Levinson components. The system supports bidirectional communication—if a linked amplifier detects a fault, it can send an error code to the preamplifier for display.

Internally, the No.431 represents a major evolution. Circuit complexity has been reduced, wiring simplified, and electrical stability improved, all contributing to very low distortion. The printed circuit boards are made of Arlon 25N, an advanced material with a stable dielectric constant and superior electrical insulation, enhancing sound performance. The dual-mono configuration includes two separate power supplies, each featuring a low-noise 660VA toroidal transformer and 24,000µF low-ESR capacitors.

Technical refinements—such as oxygen-free copper bus bars, high-frequency bypass components, matched TO-3P output transistors clamped with aluminum bars, and comprehensive protection circuits—make the No.431 exceptionally reliable. Soft-clip circuits prevent harmful saturation, while servos block DC from reaching the outputs. Voltage-gain stages are fully balanced and powered by independently regulated supplies.

The No.431 shares the elegant design, robust construction, and premium components of Mark Levinson’s flagship models like the No.33H. Though more compact and lighter, it does not compromise on performance. Compared to the No.334, it offers enhanced midrange detail and treble extension, delivering a well-defined and coherent soundstage.

Technical specifications:

• Solid-state dual-mono power amplifier
• Speaker connections: four custom-designed binding posts by Madrigal
• Inputs: two balanced 3-pin XLR, two unbalanced RCA
• Other connectors: two 1/8" mini-jacks for remote turn-on, one RS-232 port via RJ-11, two Mark Levinson Link ports via RJ-45
• Output power: 200W per channel into 8 ohms (23dBW), 400W per channel into 4 ohms (23dBW), 20Hz–20kHz, <0.5% THD (FTC rated)
• Frequency response: 20Hz–20kHz, ±0.5dB
• Input sensitivity: 130mV for 2.83V output; 1.82V for full output
• Output impedance: <0.02 ohm (20Hz–20kHz)
• Signal-to-noise ratio (main outputs): >65dB (ref. 2.83V)
• Damping factor: >400 (20Hz–20kHz into 8 ohms)
• Power consumption: 175W (On), 100W (Standby), 15W (Sleep)
• Current draw at rated output (120V): 8.5A (350W into 8 ohms), 14.6A (700W into 4 ohms)
• Dimensions: 45.1 cm (W) x 19.4 cm (H) x 51.3 cm (D)
• Net weight: 43 kg (95 lbs)