Rolls Bellari HA540 Mk2 Pure Class A Stereo Headphone Amplifier

A dedicated tube stage for headphone listening.

The Rolls Bellari HA540 MK2 combines a 12AX7 tube input stage with a MOSFET output circuit in a Class A stereo headphone amplifier. Connect the analog output of your DAC or another playback source and give your headphones a dedicated amplifier without replacing the rest of your system.

Tube input, MOSFET output

The included 12AX7 tube operates with 150 regulated volts at the plates, while the MOSFET output stage drives your headphones. A zero-feedback design offers another approach to headphone amplification for listeners who want to explore a tube-based signal path.

Connections for different listening setups

Input 1 provides RCA and 3.5 mm stereo connections, while Input 2 provides RCA connections for a second source. Both 1/4-inch and 3.5 mm stereo headphone jacks accommodate common headphone plugs. Use a source with a compatible analog output; digital sources require a separate DAC.

Broad headphone impedance compatibility

The HA540 MK2 lists support for headphones rated from 8 to 2,000 ohms. Impedance alone does not determine how much power a headphone needs, so consider headphone sensitivity and your preferred listening level when matching your setup.

At a glance

• Design: Class A stereo headphone amplifier with 12AX7 tube input and MOSFET output
• Input 1: RCA and 3.5 mm TRS stereo
• Input 2: RCA
• Headphone connections: 1/4-inch and 3.5 mm TRS stereo jacks
• Listed headphone impedance range: 8–2,000 Ω
• Input impedance: 47 kΩ
• Maximum gain: 19.6 dB
• Total harmonic distortion: 0.04%, 20 Hz–20 kHz at 1 VRMS
• Signal-to-noise ratio: 85 dB, unweighted
• Frequency response: 6 Hz–51 kHz, ±3 dB
• Crosstalk: −75 dB
• Included tube: One RUBY 12AX7
• Compatible tube types: 12AX7, 12AX7A, 7025, ECC83, 12AX7WA, and 5751
• Warm-up time: 30 seconds
• Power requirement: 15 VDC, 500 mA
• Dimensions: 6 × 2.5 × 5.4 inches (W × H × D)
• Product weight: 2 lb / 0.9 kg
• Manufacturing: Hand built in Salt Lake City, Utah

In the Box

• Bellari HA540 MK2 tube-powered headphone amplifier
• PS27s 15V power supply

Includes a limited 1-year warranty.