HA-300MK2

Direct Heated Triode
Vacuum Tube Headphone Amplifier

The Star is Reborn

Work hard and dig deep with 
20 years of impeccable track record.

Pushing the envelop of tube amplification to
deliver practicality, performance and refinement.

Tube Amplifier Holy Grail

The Pursuit of Direct Heated Triode (DHT)
 

DHT refers to triode tubes that use the cathode as

the filament and will heat up the cathode directly.

Minimal approach, offers stellar dynamic, transient 
and transparent, extremely well-received by audiophiles.

A challenge for headphone applications. Low tolerance to 
shock and vibration, sensitive to hum/interference.

The Irresistible 300B
 

The 300B is the most renowned and sought after DHT

because of its dreamy tonal characteristic. 
 

HA-300MK2 uses a matched pair of Gold Lion Genelex

PX300B low-noise audio triode as power output tubes. 

• Endure and passed the toughest tests for reliability

• Natural, sensible and realistic sound signature

• Impressive frequency extension

Purist’s One-Way Ticket 

Less is More 
 

Single-ended Triode (SET) Amplifier uses a single triode

vacuum tube to produce amplified output without 
splitting the musical signal into parts.

2-stage amplification, a pair of driver tube amplifies

signal voltage so that the 300B output tube will perform

its amplification at a very linear condition. 

Simplicity circuit design. Displace the beautiful tone of

your vacuum tubes without any cancellation.

Single-ended Driver Stage 

Cayin developed many 300B based SET amplifiers and

6SN7 is always the first choice for driver tube. 
 

HA-300MK2 uses a matched pair of Tung-Sol 6SN7GTB

to complete the two-stages SET amplification.

 
• Low noise, high price-performance and highly reliable
• Super linear and natural sounding 
• A classical tube combination adopted in many

 Cayin SET amplifier implementations

Tube Regulated Power Supply

2-Boxes Design

Outboard Power Supply minimize ripple effect, offer a

clean, low-noise power to amplification circuit.
 

Multi-stage tube regulated power supply circuit, feed

power to different amplification stages independently.

New Old Stock (NOS) Rectifier Tubes 

HA-300MK2 uses 4 x NOS 22DE4 from RCA, one of the

best versions of 22DE4 available in tube market 
 

Convert incoming power source to DC current, 
provides cleanest power with minimum interference 
for the amplification circuit.

• Unlike output tubes, rectifier tubes don’t involve heavy

lifting load, they can last very long without deteriorate.

• No matching requirement, replace on per piece based.

Power Supply Transformer
 

The outboard power supply is driven by a high 
inductance high efficiency toroidal power transformer.

Cayin design and wind the Power transformers in-house.

Low leaking design for headphone applications.
 

Premium Vacuum Tubes

Driver Tubes: Tung-Sol 6SN7GTB (Matched Pair)
 

Output Tubes: Genalex PX300B (Matched Pair)
 

Rectifier: NOS RCA 22DE4 x 4

Transformer-coupled Design

Balanced Driven from Single-ended Triode Amplifier 

The 300B SET output drives a pair of proprietary output

transformers, support both headphones and speakers.
 

The secondary winding of the output transformers

provide an alternative phase and compose a balanced

output, enables balanced driven from an SET 
amplification circuit. 
 

Both single-ended and balanced headphone output are

"original" outputs from the transformers.

In-house Designed and Winded Transformers 

With a pair of EI Transformers,  HA-300MK2 delivers a

natural and realistic sound across the frequency range.
 

Cayin design and wind the all transformers in-house

because they play a vital role in our amplifiers.
 

• Total freedom in specifying the requirements and 
  winding instructions. 
 

• Total control on material and craftsmanship.

This Is All You'll Ever Need

Impedance Matched Phone Out

Optimized its output to handle the headphone loading

according to three headphone impedance settings
Low (L): 8Ω~64Ω; Medium (M): 65Ω-250Ω; High (H): 251Ω~600Ω.
 

Matching headphone impedance should produce a natural

sound with well-defined bass reproduction, it is different

from gain control of solid state amplifier.
 

Planar Headphones are more sensitive to impedance

matching than dynamic headphones but users can try out

different impedance settings.

Carefully Optimized Headphone Outputs
 

HA-300MK2 offers three headphone outputs: 6.3mm 
single-ended, 4.4mm balanced, and 4-pin XLR balanced.
 

The XLR4 output is a full-fetched output but the 4.4mm

output is optimized for wider range of headphones,
including high sensitivity portable headphones.
 

• 4.4mm is level-matched, lower noise, lower power 
 output with the same audio performance
 

• at LOW headphone impedance, the 4.4mm output 
 delivers roughly 70% of 4-pin XLR output only.

Powerful and Effortless
 

Combinations all audiophiles will cherish and admired:

purity of single-ended triode amplifier, dreamy sound

signature of 300B, and authoritative dynamic and control

when called for.
 

With up to 6w per channel, provides all the power you

need to handle vast selection of headphones, from 
portable friendly dynamics to extremely demanding

planar.

Professionally Precision

Low noise low distortion electronic controlled resistor

ladder analogue volume controller JRC MUSE72320V,

commonly used in high-end preamplifiers and streamers.
 

4-channel in one integrated controller offers high 
precision and zero channel imbalanced.
 

ALPS balanced potentiometer as 41-steps encoder to

provide precise and intiuative control that we are all 
familiar with.

Interface Facilitates Functions

Quick-release Connection 
 

Lock-on & quick-release aviation grade copper connectors. 
 

Silver plated Teflon umbilical cable connects between

outboard power supply and amplifier circuit.

Dual Inputs
 

Balanced (XLR) and Single-ended (RCA) to cover a

variety of inputs.
 

Balanced input will go through a pair of input 
transformers, the + and – half cycle will merge  to

become a single-ended signal.

Speaker Output

Users can toggle between speaker and headphone

output.
 

With 8W per channel Class A output, the amplifier can

driver high sensitive speakers, or common bookshelf

speaker in a small listening area.
 

High quality solid brass speaker terminals.

Enhance Your Daily Usage

Anti-Interference Improves Listening Experience

Custom-made silica gel shock absorbers between critical

tube components, chassis mainframe and tube socket,

remove microphonic effectively.
 

Reinforcing shielding of transformers and effective circuit

layout to minimize interference. 

Delay Can Be Desirable
 

60sec startup delay circuit.
 

Enhances circuit protection and minimizes pop noise

during startup.

Bundled Protection
 

Specially designed vacuum tube shielding cage to

protect users from touching the red hot vacuum

tubes during operation.
 

Removing and installing with ease, safe and flexible

for different needs.

The Art of Black Finishing

13.5mm brushed Aluminum-Magnesium Alloy

front panel, added strength and corrosion 
resistance to the amplifier.
 

The panel is black anodized, it is extremely

durable and protect the amplifier from

scratches.

The Hidden Details

The chassis and transformer pots are treated by

our proprietary 14 rounds of crafting process 
composed of scratch, spray, sanding and baking.  
 

The high gross final finishing endows a refined

and delicate texture as well as protecting the

amplifier from years of long service.