The AMP18 overcomes the physical space limitations typically associated with modular amplifier cards. It employs 40 dual transistors, forming a total 80-transistor output matrix—a design that is challenging to implement within such a compact form factor.

Through careful circuit layout and the use of a large number of high-quality transistors, the AMP18 delivers higher current output, improved control over low-impedance headphones, and enhanced overall amplifier stability.

This architecture enables stronger drive capability and consistent performance across demanding headphone loads, contributing to a more controlled and accurate sound presentation.

Conventional headphone amplifiers often rely on large-loop deep negative feedback to reduce static distortion. While effective in steady-state conditions, this approach can introduce signal delay, which becomes problematic during rapid dynamic changes in music.

In passages with sudden transients—such as drum hits or complex instrumental attacks—this delay can result in slower response, reduced impact, and loss of detail.

AMP18 adopts a cascaded current feedback circuit, designed to minimize these limitations. By avoiding large-loop deep negative feedback, this architecture reduces transient distortion while maintaining control and stability.

The result is faster transient response, improved dynamic accuracy, and better preservation of musical energy across complex and demanding passages.

AMP18 employs a two-stage amplification architecture designed to balance signal accuracy and output drive.

The first stage uses operational amplifiers combined with transistors to preserve low-level detail and maintain low noise, while increasing signal drive to prevent early-stage attenuation.
The second stage adopts current mirror amplification with complementary outputs, providing the necessary current delivery for demanding headphone loads.

This structure ensures stable, linear amplification while minimizing distortion. Transient attacks remain clean and controlled, with natural decay characteristics that preserve harmonic detail and timing accuracy.

AMP18 utilizes a complementary output circuit to reduce the asymmetrical distortion commonly found in conventional transistor output stages.

By symmetrically amplifying positive and negative half-waves, the output stage maintains waveform integrity and avoids clipping artifacts that can affect low-frequency control and high-frequency extension.

AMP18 supports an external 12V DC power supply, increasing the amplifier’s voltage swing to ±12V when operating in Super Gain mode.

In this configuration, output power reaches 1740mW + 1740mW @ 32Ω, providing substantial headroom and current delivery. This allows AMP18 to drive a wide range of headphones and IEMs with authority, maintaining control across bass impact, midrange body, and extended treble response.

AMP18 is equipped with dual 4.4mm balanced outputs, functioning as both balanced phone out and dedicated balanced line out.

The 4.4mm balanced interface offers improved channel separation, higher drive capability, and better compatibility with high-end headphones and IEMs.

The dedicated balanced line output provides a clean, stable signal when connected to external headphone amplifiers, allowing AMP18 to serve as a core component in a modular Hi-Fi system together with DX340.

The AMP18 card is compatible with the DX340, and is also compatible with the DX300 and DX320 players.