Cayin HA-300MK2 black

The Cayin HA-300MK2 is a headphone amplifier that uses the 300B triode in a transformer-coupled (SET) architecture, renowned for its harmonic rendering qualities. Designed as a dual-chassis unit with a separate power supply and fully hand-crafted point-to-point wiring, it blends traditional technologies with modern audiophile expectations. It can be used as a headphone amplifier, thanks to its three dedicated outputs (single-ended and balanced), or as an amplifier for high-efficiency speakers, with 6 watts of pure Class A power.

A visionary dual-chassis architecture

The HA-300MK2’s two-module design is not merely an ostentatious aesthetic choice, but a fundamental technical necessity. This physical separation between the power supply and amplification sections radically eliminates electromagnetic interference that could degrade the audio signal.

The power supply unit houses a toroidal transformer specially developed by Cayin, along with four NOS RCA 22DE4 rectifier tubes converting AC to DC. This essential section ensures exceptionally stable power delivery, free from fluctuations and noise. Components are connected by shielded cables with aviation-grade copper connectors, ensuring perfect electrical transmission.

In the main amplification module sit the prestigious Genalex Gold Lion PX300B 300B tubes, paired with Tung-Sol 6SN7GTB driver tubes. This carefully selected tube pairing is a renowned combination among the most discerning audiophile circles. The thick metal chassis rests on damping feet that isolate the electronics from parasitic vibrations, while a silicone suspension system specifically protects the 300B tubes from microphonic effects.

The excellence of 300B triode amplification

The reputation of 300B tubes in the audiophile world is well established. These directly heated triodes (DHT) are celebrated for their unique ability to reproduce music with holographic presence and exceptional harmonic richness. Their sonic signature is characterized by natural midrange sweetness, remarkable transparency, and an ability to breathe life and emotion into recordings.

The HA-300MK2 leverages these legendary tubes in a SET (Single-Ended Triode) configuration with two amplification stages. The 6SN7 tubes first amplify the signal voltage before the 300B takes over for current amplification. This architecture ensures optimal linearity and harmonic distortion primarily composed of even-order harmonics, considered musically pleasing to the ear.

Each 300B tube is paired with its own output transformer, designed and manufactured by Cayin specifically for the HA-300MK2. These high-quality EI transformers deliver an extended frequency response from 10 Hz to 45 kHz, preserving the subtlest musical information.

Remarkable adaptive versatility

One of the HA-300MK2’s distinguishing features is its ability to precisely adapt to any headphone via its three-position impedance selector. This clever adjustment optimizes the ratio between the amplifier’s output impedance and the headphone’s impedance, ensuring ideal sound reproduction with all models on the market.

For low-impedance headphones (8-64Ω), the “Low” position offers optimal damping and perfect driver control. The “Medium” position suits models from 65-250Ω, while “High” is tailored for high-impedance headphones from 251-600Ω. Each of these settings corresponds to an independent secondary winding of the output transformer, ensuring optimal acoustic performance across the entire operating range.

The Cayin HA-300MK2 offers three complementary headphone outputs:

• A traditional single-ended 6.35 mm jack output delivering up to 5000 mW at high impedance
• A 4.4 mm balanced Pentaconn output with level matching, lower noise, and ideal for portable headphones
• A 4-pin balanced XLR direct output offering maximum power up to 6000 mW

Beyond headphones: a complete hi-fi solution

A rarity for a headphone amplifier, the HA-300MK2 also includes speaker outputs. A simple toggle switch turns the unit into a hi-fi amplifier delivering 2×8 watts of pure Class A power. While modest on paper, this output is more than sufficient to drive high-efficiency speakers (around 90 dB/W/m and above) in a medium-sized room.

Audio inputs include one unbalanced RCA pair and one balanced XLR pair, connectable to any quality source such as a CD player, an external DAC, or a network player. These balanced inputs are converted via dedicated input transformers, ensuring perfect signal integrity.

Volume control is handled by a premium 41-step ALPS potentiometer, offering extremely precise adjustment and preserving audio signal integrity, unlike many digital volume systems that degrade resolution.

Technical Specifications

Concept and Architecture

• Type: Tube headphone and speaker amplifier, pure class A, single-ended triode (SET) with output transformers
• Technology: Directly heated triodes (DHT) 300B tubes, renowned for their exceptional musicality
• Use: Hybrid headphone and speaker amplifier, with balanced and unbalanced outputs

Highlights

• Directly heated 300B amplification: holographic and natural sound reproduction
• Triple headphone output with dedicated impedance adjustment
• Speaker output 8 W + 8 W: compatible with high-efficiency speakers
• Separate external power supply for ultra-low noise
• True balanced output (no simulation)
• Hand-selected NOS and audiophile-grade components
• Exceptional build quality, designed to last

Audio Performance

• Compatible headphones: 8 Ω to 600 Ω
• Impedance adjustment (3-position selector):
  • Low (L): 8–64 Ω (optimum: 32 Ω)
  • Medium (M): 65–250 Ω (optimum: 64 Ω)
  • High (H): 251–600 Ω (optimum: 300 Ω)
• Headphone output power (per channel):
  • XLR 4: up to 6000 mW (H)
  • 4.4 mm: up to 5400 mW (H)
  • 6.35 mm: up to 5000 mW (H)
• Speaker output: 8 W + 8 W in class A
• Frequency response:
  • Headphones: 10 Hz – 45 kHz ±3 dB
  • Speakers: 10 Hz – 40 kHz ±3 dB
• Total harmonic distortion (THD): 1% @ 1 kHz
• Signal-to-noise ratio (SNR):
  • Headphones: 100 dB (A-weighted)
  • Speakers: 95 dB (A-weighted)
• Input sensitivity: 200 mV at 650 mW (headphones), 400 mV (speakers)
• Input impedance: 50 kΩ

Tubes and Components

• Output tubes: 2× Genalex PX300B
• Driver tubes: 2× Tung-Sol 6SN7GTB
• Rectifier tubes: 4× NOS RCA 22DE4
• High-voltage tube rectification for clean and stable current
• Volume potentiometer: JRC MUSES72320V with 41-step ALPS
• Coupling capacitors: MultiCap audiophile
• Internal wiring: point-to-point, shielded silver wires for ultra-clean signal

Design and Construction

• Dual chassis design:
  • Amplifier block
  • Dedicated power supply block (with shielded toroidal transformer)
• Transformers: EI and toroidal, made in-house for perfect matching
• Anti-vibration:
  • Silicone suspension system for 300B tubes
  • Shielded and filtered chassis
• Delay function: 60-second startup delay for tube protection
• VU meter: high-end, integrated on the front panel
• Tube protection grille: removable
• Power connector: aviation-grade copper locking with silver-plated Teflon cables

Connectivity

• Audio inputs:
  • 2× balanced XLR
  • 2× unbalanced RCA
• Headphone outputs:
  • 1× 6.35 mm jack (unbalanced)
  • 1× 4.4 mm Pentaconn (balanced, level adaptation)
  • 1× 4-pin XLR (balanced)
• Speaker output:
  • 1× pair of binding posts (8 W + 8 W)

Physical Characteristics

• Amplifier: 286 × 368 × 210 mm – 19 kg
• Power supply: 150 × 345 × 210 mm – 10 kg

Power Supply and Operating Conditions

• Power consumption: 185 W
• Fuses:
  • 220–240 V: T1.6AL250V
  • 100–120 V: T3.15AL250V
  • Tube: T100mAE250V