Opus Audio HDS500-500 Studio Power Amplifier

The Opus Audio HDS500-500 is a British-made, dual-mono Class A/B studio power amplifier that delivers 350W per channel into 8Ω and 500W per channel into 4Ω, combining fully linear power supplies, MUSE JFET input stages and lateral MOSFET output devices for precise, transparent studio monitoring.

Handmade in Cornwall, the HDS500-500 draws on over 40 years of Opus Audio amplification heritage. Its entirely analogue signal path eliminates digital signal processing (DSP), preserving the integrity of the original audio signal. Designed for demanding professional audio environments, the amplifier combines traditional analogue engineering with refined component technology to deliver exceptional loudspeaker control, low distortion and accurate transient reproduction.

Dual-Mono Class A/B Amplification

The HDS500-500 employs a dual-mono Class A/B architecture with independent, fully linear power supplies for each channel. This design minimises interaction between channels, improves stereo separation and supports consistent performance during demanding dynamic passages.

The amplifier delivers 350W per channel into 8Ω and 500W per channel into 4Ω, providing substantial power for professional studio monitors and high-performance passive loudspeakers. Its Class A/B topology combines the linearity associated with analogue amplification with the efficiency and power delivery required for critical listening applications.

MUSE JFET Input Stages and Lateral MOSFET Outputs

High-performance MUSE JFET input stages provide the foundation for accurate signal amplification, supporting low-noise operation and faithful reproduction of subtle musical detail.

Metal-can lateral MOSFET output devices complement the input circuitry, delivering controlled power and stable amplification. Together, these components support the amplifier's wide frequency response, low distortion and natural presentation.

The HDS500-500 maintains the engineering principles of classic analogue amplification while incorporating carefully selected semiconductor technology to meet modern studio monitoring requirements.

Exceptional Loudspeaker Control and Damping Factor

With a damping factor exceeding 1,000 into 8Ω, the HDS500-500 provides exceptional electrical control over connected loudspeakers.

This high damping factor helps minimise unwanted driver movement, particularly at low frequencies, supporting tight, controlled bass reproduction and accurate transient response. The amplifier maintains precision during complex musical passages, allowing studio monitors to reproduce dynamic changes with clarity and authority.

The result supports critical mixing, mastering and detailed listening, where accurate loudspeaker behaviour plays an essential role in reliable monitoring decisions.

Directly Coupled Loudspeaker Outputs

The HDS500-500 features directly coupled loudspeaker outputs without relays or inductors in the output signal path.

This approach removes additional components from the output path, reducing potential sources of signal alteration and supporting a direct electrical connection between the amplifier and loudspeakers.

By prioritising signal integrity, the design helps preserve the tonal balance, dynamic contrasts and fine detail of the original recording without introducing unnecessary sonic character.

100% Analogue Signal Path with No DSP

The HDS500-500 maintains a completely analogue signal path, with no digital signal processing, digital conversion or DSP-based correction.

This design prioritises direct signal amplification and allows the amplifier to reproduce audio without additional digital processing stages.

Its traditional analogue architecture makes it particularly suitable for professional monitoring systems where engineers require consistent, predictable amplification and an accurate representation of the source material.

Wide Frequency Response and Low-Noise Performance

A frequency response of 5Hz to 60kHz extends well beyond the conventional audible spectrum, supporting accurate reproduction across the audio bandwidth.

The amplifier achieves a signal-to-noise ratio exceeding 116dB, helping maintain a quiet background that reveals low-level recording detail. Crosstalk performance exceeding 102dB further supports channel separation and stable stereo imaging.

A specified THD figure of 0.003% at 1kHz into 8Ω reflects the amplifier's emphasis on low-distortion signal reproduction, allowing engineers to assess recordings without excessive amplifier-induced colouration.

Professional Studio Integration

The HDS500-500 features an input sensitivity of 2.2V RMS for full rated power and an input impedance of 10kΩ, supporting integration with suitable professional monitoring controllers, preamplifiers and line-level sources.

Its 2U chassis measures 438mm wide and 520mm deep, with an approximate weight of 30 to 35kg. The substantial construction accommodates the amplifier's fully linear dual-mono power supply architecture.

Handmade British engineering and a six-year warranty reinforce the HDS500-500's focus on long-term reliability and professional performance.

Technical Specifications

Amplifier topology: Dual-mono Class A/B.

Power output into 8Ω: 350W per channel.

Power output into 4Ω: 500W per channel.

Power supplies: Fully linear, dual-mono configuration.

Input stages: MUSE JFET.

Output devices: Metal-can lateral MOSFET.

Signal path: 100% analogue, without DSP.

Loudspeaker outputs: Directly coupled, with no output relays or inductors.

Input sensitivity: 2.2V RMS for full power.

Input impedance: 10kΩ.

Frequency response: 5Hz to 60kHz.

Signal-to-noise ratio: Greater than 116dB.

Crosstalk: Greater than 102dB.

Total harmonic distortion: 0.003% at 1kHz into 8Ω, subject to confirmation.

Damping factor: Greater than 1,000 into 8Ω.

Dimensions: 2U height, 438mm width and 520mm depth.

Weight: Approximately 30 to 35kg.

Manufacture: Handmade in the UK.

Warranty: 6 years.

Why Choose the Opus Audio HDS500-500?

• Hear recordings with greater confidence: Transparent analogue amplification helps preserve the detail and tonal character essential for critical mixing and mastering.

• Maintain tight, accurate bass: An exceptionally high damping factor provides precise loudspeaker control for improved low-frequency definition.

• Power demanding studio monitors: Up to 500W per channel into 4Ω provides substantial headroom for professional monitoring applications.

• Experience natural analogue reproduction: A completely analogue signal path avoids unnecessary digital processing.

• Identify subtle recording details: Low-noise circuitry and excellent channel separation support precise stereo imaging and detailed listening.

• Invest in British engineering: Handmade UK construction, over 40 years of amplification heritage and a six-year warranty provide long-term reassurance.

• British-made dual-mono Class A/B studio power amplifier.
• 350W per channel into 8Ω and 500W per channel into 4Ω.
• Fully linear, independent dual-mono power supplies for consistent power delivery and improved channel separation.
• 100% analogue signal path with no DSP or digital conversion.
• High-performance MUSE JFET input stages for low-noise, accurate signal amplification.
• Metal-can lateral MOSFET output devices for controlled, low-distortion power delivery.
• Damping factor exceeding 1,000 into 8Ω for exceptional loudspeaker control and tight bass reproduction.
• Directly coupled loudspeaker outputs with no relays or inductors in the output signal path.
• Extended 5Hz to 60kHz frequency response for wide-bandwidth audio reproduction.
• Signal-to-noise ratio greater than 116dB for revealing subtle recording details.
• Crosstalk performance exceeding 102dB for precise stereo separation and imaging.Low-distortion design for transparent, accurate studio monitoring.
• 2.2V RMS input sensitivity for full rated power.
• 10kΩ input impedance for integration with suitable professional audio equipment.
• Robust 2U chassis measuring 438mm wide and 520mm deep.
• Approximate weight of 30 to 35kg.
• Handmade in the UK, drawing on over 40 years of Opus Audio amplification heritage.
• Six-year manufacturer's warranty.

This item, like everything we supply, comes with the complete support of our expert team. Our excellent technicians have been specifying, building and supporting studios for over twenty years. If you have any problems with installation, setup or everyday use, they’re never more than a click away, and always happy to help.

You can contact them here.