Fully-balanced power for your headphones

The Ferrum ERCO headphone DAC/amp combines an ESS Sabre ES9028PRO DAC with fully-balanced amplification derived from Ferrum’s OOR. It delivers up to 6.1 W into 50 ohms through its balanced headphone output and supports PCM up to 32-bit/384kHz and DSD256. USB-C, optical, coaxial, and RCA inputs connect digital and analog sources, while XLR and RCA outputs extend its role to powered speakers.

6.1W into 50Ω

ERCO’s proprietary amplifier uses four Linear Technology LT1210 current feedback amplifiers, fine-tuned with discrete components. Its signal path remains balanced from the early conversion stage, and RCA input signals are converted to balanced operation. With 1.2 W into 300 ohms and 6.1 W into 50 ohms from the balanced output, ERCO provides substantial power across different headphone loads.

High-resolution digital conversion

An ESS Sabre ES9028PRO chip works within Ferrum’s in-house conversion topology. Ferrum programmed the ARM processor specifically for ERCO to optimize its USB, coaxial, and optical digital inputs for audio. USB-C supports PCM up to 32-bit/384kHz and DSD256, while the coaxial and optical inputs accommodate additional digital sources.

Two headphone outputs and three gain settings

Choose the balanced 4.4mm headphone output or the single-ended 6.35mm output to match your cable. Three gain settings let you adjust amplification for headphones with different sensitivities. Headphone output impedance below 0.3 ohms helps limit tonal changes caused by interaction with a headphone’s impedance.

Analog control for headphones and speakers

ERCO’s analog volume control adjusts listening level directly. Balanced XLR and unbalanced RCA line outputs connect to powered speakers or external amplification. A volume bypass option applies to the line outputs when another component handles volume control. The RCA analog input also lets ERCO serve as a headphone amplifier for an external source.

Dedicated MQA processing

ERCO includes both MQA decoding and rendering. Its ARM-optimized processing supports MQA playback within the same component that handles digital conversion and headphone amplification.

Compact construction with direct controls

Three knobs handle ERCO’s settings. Black anodized aluminum and corten steel carry Ferrum’s design language into a chassis measuring 8.6 × 8.1 × 2.0 inches (21.7 × 20.6 × 5 cm). Its compact footprint leaves room for other components on a desk or equipment shelf.

Ready to pair with HYPSOS

ERCO supports Ferrum’s HYPSOS power supply through its proprietary four-pin Ferrum Power Link connector. A conventional DC input provides another power connection option, allowing you to choose the power supply arrangement that suits your system.

Product highlights

• Fully-balanced headphone DAC/amp with amplification derived from the OOR
  
• ESS Sabre ES9028PRO DAC
  
• Up to 6.1 W into 50 ohms through the balanced headphone output
  
• PCM up to 32-bit/384kHz and DSD256
  
• Balanced 4.4mm and single-ended 6.35mm headphone outputs
  
• Three headphone gain settings
  
• USB-C, optical, coaxial, and RCA inputs
  
• Balanced XLR and unbalanced RCA line outputs
  
• Analog volume control with line-output bypass
  
• MQA decoder and renderer
  
• Four-pin Ferrum Power Link connection for HYPSOS
  
• Black anodized aluminum and corten steel chassis

Specs

• Amplifier: Fully-balanced proprietary IC power amplifier
  
• DAC chip: ESS Sabre ES9028PRO
  
• Balanced headphone gain: −5.8 dB, +6 dB, +17.8 dB
  
• Single-ended headphone gain: −11.8 dB, 0 dB, +11.8 dB
  
• Analog input: RCA, consumer level
  
• Digital inputs: USB-C, optical S/PDIF, coaxial S/PDIF
  
• Optical input support: Up to 24-bit/96kHz and DoP64
  
• Coaxial input support: Up to 24-bit/192kHz and DoP64
  
• PCM support: Up to 32-bit/384kHz
  
• PCM sample rates: 44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384kHz
  
• DSD support: Up to DSD256
  
• DSD sample rates: 2.8224, 3.072, 5.6448, 6.144, 11.2896, 12.288MHz
  
• MQA: Decoder and renderer
  
• Headphone outputs: Balanced 4.4mm, single-ended 6.35mm
  
• Line outputs: Balanced XLR, unbalanced RCA, consumer level
  
• Volume control: Analog, with bypass for line outputs only
  
• Balanced output power: 1.2 W into 300 ohms, 6.1 W into 50 ohms
  
• Single-ended output power: 300 mW into 300 ohms, 1.7 W into 50 ohms
  
• Frequency response: 10Hz–30kHz (±0.05 dB), 10Hz–greater than 200kHz (±1 dB)
  
• Balanced output THD: Less than 0.00018% (−115 dB) at 1 mW and 100 mW into 16 ohms
  
• Single-ended output THD: Less than 0.00032% (−110 dB) at 1 mW into 16 ohms, less than 0.00057% (−105 dB) at 100 mW into 16 ohms
  
• Analog dynamic range: 130 dB, A-weighted
  
• Digital dynamic range: 120 dB, A-weighted
  
• Input impedance: 47 kilohms
  
• RCA preamp output impedance: 22 ohms
  
• XLR preamp output impedance: 44 ohms
  
• Headphone output impedance: Less than 0.3 ohms
  
• Power inputs: 5.5/2.5mm center-positive DC connector, proprietary four-pin Ferrum Power Link connector
  
• Power adapter specification: 100–240V AC to 22–30V DC
  
• Idle power consumption: Less than 15 W
  
• Dimensions (W × D × H): 8.6 × 8.1 × 2.0 inches (21.7 × 20.6 × 5 cm)
  
• Weight: 3.97 lb (1.8 kg)

What’s included

• Ferrum ERCO Gen 2 headphone DAC/amp
  
• Additional package contents are not specified in the supplied documentation.