Cayin HA-300MK2 silver

The Cayin HA-300MK2 is a headphone amplifier that uses the 300B triode in a transformer-coupled (SET) architecture, renowned for its harmonic reproduction qualities. Designed with a dual-chassis layout featuring a separate power supply and entirely hand-wired point-to-point circuitry, it combines traditional technologies with modern audiophile expectations. It can be used as a headphone amplifier, thanks to its three dedicated outputs (unbalanced and balanced), or as an amplifier for high-efficiency speakers, delivering 6 watts of pure class A power.

A Visionary Dual-Chassis Architecture

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

The power supply block houses a toroidal transformer specially developed by Cayin, along with four NOS RCA 22DE4 rectifier tubes that convert alternating current into direct current. This essential section ensures exceptionally stable power delivery, free from fluctuations and noise. Components are connected by shielded cables with aviation-grade copper connectors, guaranteeing perfect electrical transmission.

The main amplification module features the prestigious Genalex Gold Lion PX300B tubes, paired with Tung-Sol 6SN7GTB driver tubes. This carefully selected tube combination is renowned among the most demanding audiophile circles. The thick metal chassis rests on damping feet that isolate the electronics from unwanted 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 acclaimed for their unique ability to reproduce music with holographic presence and exceptional harmonic richness. Their sonic signature is characterized by natural midrange smoothness, remarkable transparency, and an ability to bring life and emotion to recordings.

The HA-300MK2 harnesses these legendary tubes in a two-stage SET (Single-Ended Triode) configuration. The 6SN7 tubes first amplify the signal voltage before the 300B tubes take over for current amplification. This architecture ensures optimal linearity and harmonic distortion mainly composed of even-order harmonics, which are 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 provide an extended frequency response from 10 Hz to 45 kHz, preserving the subtlest musical details.

Remarkable Adaptive Versatility

One of the HA-300MK2’s standout features is its ability to precisely adapt to any headphone thanks to its three-position impedance selector. This ingenious adjustment optimizes the ratio between the amplifier’s output impedance and that of the headphones, 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 designed 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 usage range.

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

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

Beyond Headphones: A Complete Hi-Fi Solution

A rare feature for a headphone amplifier, the HA-300MK2 also includes outputs for loudspeakers. A simple toggle switch transforms the device into a hi-fi amplifier delivering 2×8 watts in pure class A. While this power may seem modest, it is more than sufficient to drive high-efficiency speakers (90 dB/W/m and above) in a medium-sized room.

Audio inputs include a pair of unbalanced RCA and a pair of balanced XLR connectors, compatible with any quality source such as a CD player, external DAC, or 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 amplifier for headphones and speakers, 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