Yamaha A-S501 Integrated Amplifier

Yamaha has been building instruments, tuning concert halls, and engineering audio equipment since 1887 — and that institutional knowledge of how music actually sounds is baked into every circuit decision in the A-S501. This is a 85-watt-per-channel integrated amplifier designed around Yamaha's ToP-ART (Total Purity Audio Reproduction Technology) philosophy: a strictly symmetrical left/right layout, an ART Base chassis with a solid center bar that damps resonance before it can color the sound, and direct signal paths wherever the engineering allows. At $599, it competes in a segment crowded with receivers masquerading as integrated amplifiers — the A-S501 is the genuine article.

The built-in DAC accepts optical and coaxial digital inputs, so a TV, Blu-ray player, or streamer connects directly without an outboard converter. A phono MM stage handles a turntable. Pure Direct mode strips the signal down to the shortest possible circuit route — tone controls, loudness, and buffer amp all bypassed — for sessions when you want nothing between the source and the speakers. The damping factor of 240 gives the amplifier a firm grip on woofer cones, which translates directly to tighter, more controlled bass regardless of what speakers you pair it with.

The front panel is brushed aluminum, the volume control is smooth, and the input selector is a weighted rotary encoder with LED indicators rather than the flimsy selector switches common at this price. Yamaha also engineered in Bluetooth adapter compatibility (YBA-11, optional) for casual listening without disrupting the direct-signal architecture. The A-S501 is the kind of amplifier that rewards you whether you're running vintage speakers, a new stand-mount, or a full floor-standing system — and it won't embarrass itself next to components that cost twice as much.

ToP-ART Symmetrical Architecture. Left and right channels run in strict mirror symmetry from input to output binding post — the shortest possible path, with no channel crosstalk from shared circuitry. This is Yamaha's foundational design discipline, carried from their flagship C-5000 / M-5000 separates down into the A-S501.

Pure Direct Mode. Activates a bypass that removes the tone controls, loudness circuit, and buffer amplifier from the signal path entirely. What you hear is the source, the volume control, the power stage, and your speakers — nothing else.

Built-In DAC with Optical and Coaxial Inputs. A digital-to-analog converter is integrated into the chassis, accepting one optical (TV) and one coaxial (Blu-ray / streamer) source. No outboard DAC required for a modern digital-source system.

Phono MM Stage. A proper moving-magnet phono stage is on board, correctly loaded and quietly implemented — a direct connection for any turntable with an MM or high-output MC cartridge.

Damping Factor of 240. A high damping factor means the amplifier actively controls the back-EMF from the woofer, reducing overhang and smear in the bass. At 240, the A-S501's grip on your woofers is well above average for its class.

ART Base Chassis. The reinforced base with a solid center bar isolates the internal components from external vibration and suppresses resonance within the chassis — an engineering detail that shows up as a quieter noise floor in use.

Specifications

• Channels: 2
• Minimum RMS Output Power (8 ohms, 20 Hz–20 kHz, 0.019% THD): 85 W + 85 W
• High Dynamic Power per Channel (8 / 6 / 4 / 2 ohms): 130 / 150 / 185 / 220 W
• Total Harmonic Distortion (CD to Speaker Out, 20 Hz–20 kHz, 50 W / 8 ohms): 0.019%
• Signal-to-Noise Ratio (CD, input shorted, 200 mV): 99 dB
• Damping Factor (8 ohms): 240
• Frequency Response: 10 Hz – 100 kHz, +/– 1.0 dB
• Digital Inputs: 1 × Optical (TOSLINK), 1 × Coaxial (RCA)
• Analog Audio Inputs: 8 total (includes Phono MM, CD, Tuner, Line 1, Line 2)
• Analog Audio Outputs: 2 (includes Subwoofer Pre-Out)
• Phono Stage: MM (moving magnet)
• Speaker Terminals: A, B, or A+B (dual speaker system)
• Pure Direct Mode: Yes
• Loudness Control: Continuously variable
• Bluetooth: Compatible with optional YBA-11 Bluetooth adapter (aptX)
• Auto Power Standby: Yes (after approximately 8 hours of inactivity)
• Standby Power Consumption: 0.5 W
• Dimensions (W × H × D): 17-1/8" × 6" × 15-1/4"
• Weight: 22.7 lbs.
• Finish Options: Silver, Black