e.One REF501S Stereo Amplifier

The REF501S Stereo Amplifier delivers powerful, high-resolution performance from a compact, all-aluminum chassis. Its refined analog topology, high current capability, and responsive 250-watt output offer remarkable speed, control, and accuracy—providing a stable, low-distortion foundation for any system.

The REF501S stereo amplifier, solidly built all-aluminum compact chassis, delivers dynamic, accurate high-resolution sound at 250 Watts with incredible speed and control.

• Max Power Output 250W @1% THD per Channel
• Minimum Load: 2 ohms per Channel
• Peak Output Current: 17.5 Amps per Channel
• Balanced Input Impedance: 95 Kohms
• Voltage Gain 27dB

The REF501S delivers reference-level power with precision and control, pairing a compact all-aluminum chassis with a fast, high-current design. Its 250-watt output, low-distortion performance, and wide input impedance create a clean, stable platform that preserves detail, tone, and dynamic impact—bringing lifelike clarity and authority to every listening session.

REF501S Stereo Amplifier Features

Impedance Optimized Input Stage uses selected precision resistors in a balanced high Common Mode Rejection, low output impedance driver that is critical to the amplifier's performance, ensuring that the refined dynamic qualities of the recording are preserved.

DC Signal Path

The REF501S is DC coupled with no coupling capacitor in the signal path. This optimizes the audio signal quality and maximizes both micro and macro dynamic performance. The amplifier will protect itself and your speakers if excess DC is detected with very fast shut-off.

At the Core

High-speed ultra-efficient switch mode amplification delivers literally unheard-of levels of performance using an innovative 5th order loop filter. This technology provides extremely low noise and distortion performance over the entire audio bandwidth, allowing the musical message to come through unchanged and with remarkable purity.

Why Class D?

Well-designed Class D switching supplies generally sound more open through the midrange with better Bass control. Note that 250W is 23.9dBw, which means that it will drive an 85dB speaker to 108dB with 111dB peaks, theoretically. In a large room with the volume control 10dB below max, we're measuring about 25W of continuous power. This is loud! Most power concerns are more about control rather than how much real power is delivered. This gives further advantage to Class D and switching power supplies, as their efficiency is high even at lower power outputs, helping them sound 'bigger'.

WBT NextGen Speaker Connectors

The WBT NextGen connectors provide the best possible connection from the amplifier to the speaker cables. We choose them because they impart minimal sonic signature to the sound, remaining open and grain-free up throughout the audio frequency band.