The Cayin HA-1A MK3 is a fully tube headphone amplifier, designed with Single-Ended Class A circuitry and manually wired Point-to-Point internal wiring. Its design combines a tube amplification section, headphone outputs with single-ended and balanced connections, and a variable preamplifier output. It is intended for headphone listening and integration into an audio system with sources equipped with RCA outputs.

Tube structure and circuitry

The tube section uses two JJ 12AU7/ECC82 tubes for voltage amplification and two Electro-Harmonix EL84EH/6BQ5 tubes for power amplification. The EL84EH tubes operate in a Single-Ended Class A configuration, while the Point-to-Point internal wiring manually connects the circuit components. This setup defines the construction character of the Cayin HA-1A MK3 without using modules or configurations other than those stated.

The model also incorporates output transformers developed specifically for this amplifier. The power supply features separate sections for the voltage amplification stage and the power stage; the latter also has a regulated high-voltage power supply. The product incorporates a start-up delay of approximately 50 seconds, as stated in the project specifications. A removable protective cage is positioned above the tubes.

Headphone outputs and impedance matching

The Cayin HA-1A MK3 offers two different headphone outputs. The 6.35 mm jack connection is single-ended and provides a declared power of 2,500 mW + 2,500 mW. The 4-Pin XLR output is balanced and reaches 2,800 mW + 2,800 mW. The values are expressed for the two channels and clearly distinguish the nominal performance of the two connections.

The panel includes impedance matching selection, with two dedicated ranges:

• Low: from 8 to 150 Ohm;
• High: from 151 to 600 Ohm.

The selection allows you to set the range corresponding to the impedance of the connected headphones. Before listening, it is therefore advisable to check the headphones’ nominal value and select the Low or High position. The 6.35 mm jack is suitable for headphones with a standard connector of this format, while the XLR output requires a compatible four-pin balanced connection.

Audio specifications of the headphone output

The declared frequency response is between 20 Hz and 24 kHz, with a tolerance of ±3 dB. The signal-to-noise ratio of the headphone output is 110 dB, A-weighted. Total harmonic distortion is specified at 0.3% at 1 kHz and 200 mW; at rated power it remains within 5%. Sensitivity is specified in the range from 1,200 to 2,000 mV.

These data describe the reference conditions used for the amplifier specifications. Frequency response, signal-to-noise ratio and distortion are distinct parameters: the first concerns the declared frequency range, the second the ratio between signal and noise, and the third the harmonic distortion measured under the stated conditions. Power varies instead according to the output used and the selected impedance range.

Inputs and preamplifier output

For connecting sources, the Cayin HA-1A MK3 has two RCA audio inputs. This allows analog sources with RCA outputs to be connected and the signal sent to the headphone section to be selected. The RCA connections use the usual left- and right-channel analog layout.

There is also a pair of variable-level PREAMP Out RCA outputs. The preamplifier output reaches a maximum voltage of 5 V, has a gain of 9 dB and a declared output impedance of 2.0 kOhm. The input sensitivity of the preamplifier section is 750 mV. These values are useful for assessing connection to an audio device with a compatible analog input.

For the PREAMP section, harmonic distortion of 0.1% at 2 V RMS and a signal-to-noise ratio of 105 dB, A-weighted, are also declared. The variable RCA output can therefore be used to send the signal to an additional audio device, taking into account the impedance and maximum voltage stated in the specifications.

Use and installation

The basic connection involves plugging the source into one of the two RCA inputs and connecting the headphones to the appropriate output. For headphones with a standard connection, use the 6.35 mm single-ended jack; for headphones designed for balanced connection, the four-pin XLR output can be used. The choice between Low and High must follow the nominal impedance of the connected model.

Before proceeding, it is advisable to leave sufficient space around the unit and the tube cage. The device reaches an operating temperature typical of tube equipment: it is therefore important not to cover the openings or place objects on top of the protective cage. The approximately 50-second start-up delay is part of the declared operation and must be taken into account when switching on.

The protective cage is removable, but removing it exposes the tubes. Any work on the tubes or inside the unit must be carried out only by qualified personnel and with the product disconnected from the power supply. The specified tubes are part of the model’s declared configuration.

Dimensions, power consumption and placement

With dimensions of 240 × 240 × 140 mm, the Cayin HA-1A MK3 has a compact width and depth, while requiring a stable surface suitable for the presence of the tubes. The net weight is 8.8 kg. The declared maximum power consumption is 60 W.

The dimensions must be considered together with the space needed to connect the RCA cables, the 6.35 mm jack or the four-pin XLR connector. Placement must also allow access to the controls and impedance matching selection. The model is available in silver and black finishes, according to the intended commercial configuration.

In summary

The Cayin HA-1A MK3 combines Single-Ended Class A tube circuitry, two RCA inputs, a variable PREAMP Out and two headphone output formats. The JJ 12AU7/ECC82 tubes handle voltage amplification, while the Electro-Harmonix EL84EH/6BQ5 tubes are dedicated to power. The Low/High selection covers headphones from 8 to 600 Ohm through two separate ranges. Specifications include up to 2,500 mW per channel through the 6.35 mm jack and up to 2,800 mW per channel through the balanced XLR output, with a frequency response from 20 Hz to 24 kHz ±3 dB. Thanks to the RCA preamplifier output, it can also be integrated into a broader analog audio chain, respecting the declared electrical parameters.

Main features

• Inputs: RCA
• Headphone outputs: 6.35 mm single-ended; 4-Pin XLR balanced
• Signal-to-noise ratio: 110 dB, A-weighted
• Power consumption: maximum 60 W
• Amplifier type: Fully tube headphone amplifier
• Operating class: Single-ended Class A

Technical specifications

Main device/unit technical weight	8.8 kg
Inputs	RCA
Headphone outputs	6.35 mm single-ended; 4-Pin XLR balanced
Signal-to-noise ratio	110 dB, A-weighted
Power consumption	maximum 60 W
Amplifier type	Fully tube headphone amplifier
Operating class	Single-ended Class A
Circuitry	Single-Ended Class A
Device type	Tube headphone amplifier
Dimensions	240 × 240 × 140 mm
Distortion	0.3 at 1 kHz and 200 mW output %
Frequency response	20 Hz – 24 kHz, ±3 dB
6.35 mm headphone output power	2500 mW + 2500 mW
6.35 mm headphone output	Single-ended
6.35 mm headphone output power	Up to 2.5 W per channel
XLR headphone output	Four-pin XLR
4-Pin XLR headphone output power	2800 mW + 2800 mW
Height	140 mm
High impedance matching	151–600 Ohm
Low impedance matching	8–150 Ohm
Internal wiring	Point-to-point
Depth	240 mm
Maximum output voltage	5 V
Output transformers	Developed specifically for the model
Outputs	RCA PREAMP Out, 6.35 mm, 4-Pin XLR
Power supply design	Separate power supply for the voltage gain and power sections; regulated high-voltage power supply for the power section
Power tubes	2 × Electro-Harmonix EL84EH/6BQ5
PREAMP gain	9 dB
PREAMP input sensitivity	750 mV
PREAMP maximum voltage	5 V

Technical insights

The specifications provided help compare the product’s configuration, compatibility and performance.

Related products

Cayin Soul 170HA · Xindak MT2(II) · Cayin HA-2A

Frequently asked questions

How many RCA sources can I connect to the Cayin HA-1A MK3?

The Cayin HA-1A MK3 has two RCA audio inputs, intended for connecting analog sources with RCA outputs.

Which headphone outputs are available?

There is a 6.35 mm single-ended jack output and a four-pin balanced XLR output. The declared power is 2,500 mW + 2,500 mW through the jack and 2,800 mW + 2,800 mW through the XLR output.

How is impedance matching selected?

The selector offers two ranges: Low for headphones from 8 to 150 Ohm and High for headphones from 151 to 600 Ohm.

Can the model be connected to another audio device?

Yes. A pair of variable-level RCA PREAMP Out outputs is available, with a maximum voltage of 5 V, a gain of 9 dB and a declared output impedance of 2.0 kOhm.

Which tubes does the amplifier use?

The configuration includes two JJ 12AU7/ECC82 tubes for voltage amplification and two Electro-Harmonix EL84EH/6BQ5 tubes for power amplification.