Class-A Tube amp with two gain settings

The MT-04 is a balanced hybrid headphone amplifier that pairs two 6H3 vacuum tubes with a transistor-based Class A output stage. Its tube pre-amplification stage lends warmth and body to vocals, while the transistor stage provides the current necessary for headphones. Balanced and single-ended connections, two gain settings, and up to 2200mW into 32Ω give it flexibility across a range of headphones.

A hybrid approach to headphone amplification

The MT-04 assigns preamplification to vacuum tubes and power amplification to transistors. This architecture combines the tonal character of tubes with the drive and control of a solid-state output stage, supporting full vocals, responsive bass, and clear musical detail.

Two 6H3 tubes for a warmer presentation

Two 6H3 vacuum tubes shape the signal before it reaches the power stage. Their presentation emphasizes smooth vocals, a full midrange, and delicate treble, giving voices and instruments a sense of body.

Class A output with up to 2200mW

The transistor-based Class A stage delivers up to 2200mW into 32Ω through the balanced headphone output and 1800mW into 32Ω through the single-ended output. It provides fast transient response and bass control to help preserve definition as arrangements become more demanding.

Balanced and single-ended connections

Connect your source through RCA, balanced XLR, or balanced 4.4mm inputs. On the front panel, balanced 4.4mm and 1/4-inch (6.35mm) single-ended headphone outputs accommodate two common cable terminations. The balanced output offers a specified 125dB signal-to-noise ratio and 85dB crosstalk performance.

Two gain settings within reach

A front-panel switch selects between +12dB and +18dB gain. Choose the setting that suits your headphones’ sensitivity and your source’s output level, then adjust listening volume with the rotary control.

Audio-grade capacitors

ELNA audio coupling capacitors and Rubycon filter capacitors serve the signal and power circuits. These components support the amplifier’s coupling and filtering requirements.

An external ground connection

A rear-panel ground terminal provides an external grounding point to help reduce static interference and hum associated with ungrounded enclosures.

Delayed startup and circuit protection

A relay protection circuit introduces a 30-second power-on delay to allow the tubes to warm up before listening. It also suppresses switching pops and automatically cuts power in response to overload or short-circuit conditions to help protect the amplifier and connected headphones.

A clear view of the circuitry

The aluminum alloy enclosure provides structural strength and electromagnetic shielding. Clear acrylic front and rear panels reveal the internal components, with the two vacuum tubes visible above the circuit board.

Product highlights

• Hybrid tube-transistor headphone amplifier
  
• Two 6H3 vacuum tubes for preamplification
  
• Transistor-based Class A output stage
  
• Up to 2200mW balanced output into 32Ω
  
• RCA, balanced XLR, and balanced 4.4mm inputs
  
• Balanced 4.4mm and single-ended 1/4-inch (6.35mm) headphone outputs
  
• Selectable +12dB and +18dB gain
  
• ELNA coupling capacitors and Rubycon filter capacitors
  
• External ground terminal
  
• 30-second startup delay with overload and short-circuit protection
  
• Aluminum alloy body with clear acrylic front and rear panels

Specs

• Model: MT-04
  
• Amplifier architecture: Hybrid tube-transistor
  
• Output stage: Class A
  
• Vacuum tubes: 2 × 6H3
  
• Power supply: 12V DC, 2A
  
• Inputs: RCA analog, balanced XLR, balanced 4.4mm
  
• Headphone outputs: Balanced 4.4mm, single-ended 1/4-inch (6.35mm)
  
• Frequency response: 10Hz–60kHz (±0.5dB)
  
• Gain: +12dB / +18dB
  
• Dimensions: 5.35 × 4.33 × 3.19 inches (13.6 × 11.0 × 8.1cm)
  
• Weight: Approximately 1.34lb (0.61kg)
• Single-ended headphone output
  • Output power at 32Ω: 1800mW
    
  • Output power at 75Ω: 1000mW
    
  • Output power at 150Ω: 650mW
    
  • Output power at 300Ω: 330mW
    
  • Output power at 600Ω: 165mW
    
  • Crosstalk: 76dB
    
  • SNR: 118dB
    
  • THD: 0.1% (-60dB)
• Balanced headphone output
  
  • Output power at 32Ω: 2200mW
    
  • Output power at 75Ω: 1200mW
    
  • Output power at 150Ω: 800mW
    
  • Output power at 300Ω: 400mW
    
  • Output power at 600Ω: 200mW
    
  • Crosstalk: 85dB
    
  • SNR: 125dB
    
  • THD: 0.08% (-62dB)

What’s included

• Package contents were not specified in the supplied product information.