Hi Fi/Home Theatre & Portable Audio

Cayin HA-2A, Compact Tube Headphone Amplifier

The new HA-2A will be available by mid-March 2024.​

The HA-2A is a member of Cayin’s HA headphone amplifier series, which includes the well-known HA-300MKii, HA-6A, and HA-3A. Now, with the addition of the HA-2A, which has a consistent layout and panel style with the HA series, featuring dual cold-light VU meters. At the same time, the HA-2A is also one of the members of Cayin’s new desktop system, forming a four-piece suit with the iDAP-8, iDAC-8, and iHA-8. The iHA-8 is a fully balanced class A solid-state headphone amplifier, while the HA-2A is a single-ended class A vacuum tube headphone amplifier. Together with the iDAP-8 digital transport and iDAC-8 DAC, they form a compact desktop audio headphone system, combining the characteristics of tube and solid-state amplification for different sonic experiences.

HA-2A is different from other HA series in that it is Cayin’s first vacuum tube headphone amplifier designed with all vintage NOS tubes. NOS (New Old Stock) refers to a tube that has never been used and is from old production. The amplifier consists of a total of five tubes, with the RCA 17AX4GT serving as the rectifier tube, supplying power to the plate electrode of the preamp tubes. This will fully exert the unique harmonic richness and warm, delicate audio characteristics of tube rectification.

The preamp and power tubes both use the renowned “Bugle Boy” Amperex vacuum tubes and Amperex is a vacuum tube brand that serious vacuum tube users are all too familiar with. The two Amperex ECF82/6U8 in the preamp stage and two Amperex 17BF11 in the power output stage have to go through a rigorous in-house testing and matching process before we can install them to our amplifier.

Cayin has been making tube amplifiers for 30 years, and we have accumulated years of know-how and development experience in the vacuum tube audio business. Our profound research experience and massive inventory of various types of audio tubes play a vital role in HA-2A development. The HA-2A uses NOS vintage tubes exclusively, which can be considered as using the best of our tube inventory.

The ECF82/6U8 and 17BF11 tubes used in the HA-2A were likely produced in the early 1950s, so they belong to the American production period, not the Dutch production period. They were specifically used in the audio section of early tube televisions and almost became the standard configuration for TV audio at that time.

The Amperex ECF82/6U8 is a composite tube that combines a high-gain pentode and a medium-gain triode. Cayin’s design engineers make full use of its low internal resistance and low noise characteristics, employing unique and ingenious design, wiring methods, and power supply arrangements to achieve rich, warm, balanced, and harmonious sound characteristics in the listening experience.

The Amperex 17BF11 is a dual pentode composite tube that was originally used with one pentode for voltage amplification and the other for power amplification in early applications. However, in the HA-2A, Cayin’s engineers have designed it to always work in a single-ended class A mode, carefully designing the gain circuit and incorporating an in-house developed Z11 iron core EI output transformer that is ultimately responsible for driving the headphones.

HA-2A is different from the previous HA headphone amplifiers because the rated frequency response of HA-2A can reach 20Hz-50 kHz at +/- 3dB range. This is a very impressive figure among our HA series tube headphone amplifiers. Like other Cayin HA amplifiers, the HA-2A is constructed using point-to-point welding to ensure the shortest signal path and enhance the transparency and refinement of audio performance. It features RCA and XLR dual inputs and is equipped with 6.35mm, 4-pin XLR balanced, and 4.4mm balanced headphone outputs. It also offers high, medium, and low impedance adjustment modes, making it convenient for users to pair with headphones of different impedance and driving requirements (Known as Impedance Matched Output that existed across all HA series headphone amplifiers). The unit is compact and weighs only 10kg, making it relatively small among tube headphone amplifiers and very suitable for desktop use.

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