The JAVA Hi-Fi Carbon Double Shot 400 combines an LDR-based preamplifier and GaN FET power amplifier in a single enclosure. Its fully balanced dual-mono signal path delivers high power, precise channel control and direct signal transmission for demanding stereo systems.

Alongside its line-level sources, the amplifier includes an 18-bit NOS R-2R DAC based on two Analog Devices AD1865 chips, an MM phono stage and Bluetooth aptX connectivity. A headphone output, fixed-level and variable-level XLR outputs, and a remote control for volume and source selection provide flexible integration into a wide range of audio systems.

The Carbon Double Shot 400 features a next-generation Class D output stage based on gallium nitride transistors. Compared with conventional silicon MOSFETs, GaN FET technology enables faster switching that more closely approaches the theoretical ideal, supporting high linearity, low distortion and reduced electromagnetic emissions.

JAVA GaN modules operate in a closed control loop at switching frequencies between 400 and 500 kHz. Selected through laboratory measurements and listening tests, this operating range balances efficiency, stability and sound quality, while the amplifier delivers a rated output of 400 W per channel into 8 Ω.

Instead of a conventional potentiometer, the preamplifier stage uses light-dependent resistors, or LDRs, for volume control. The control current adjusts the brightness of an internal LED, and the resulting light intensity changes the resistance to set the signal level.

JAVA’s proprietary LDR circuit separates the audio signal path from the control electronics and employs contactless input switching. With no metal or carbon wiper of the type used in conventional volume controls placed in the signal path, the sensitive analogue signal can follow a short and direct route.

The design uses NSL32SR3 LDRs. The passive preamplifier stage provides precise volume control without introducing an active gain device, while both volume and source selection can also be operated remotely.

The Double Shot configuration uses a fully balanced dual-mono topology. Separate processing for the left and right channels supports consistent operation across both sides of the stereo system, reduces interaction between channels and contributes to precise spatial imaging.

Four pairs of balanced XLR line inputs allow multiple analogue sources to be connected. The rear panel also provides one pair of fixed-level and one pair of variable-level XLR outputs, allowing the amplifier to be integrated with external components or additional power amplifiers.

The balanced signal path operates as a unified system from the LDR preamplifier stage through to the GaN FET power amplification. This design combines high output power with direct signal routing and separate handling of the left and right channels.

The built-in USB DAC is an 18-bit non-oversampling (NOS) R-2R converter based on two Analog Devices AD1865 chips. It supports files with sampling rates up to 768 kHz and is powered by a dedicated linear voltage regulator. Native MSB adjustment within the AD1865 improves linearity, particularly around the zero-crossing point, with the aim of producing smoother signal transitions and reducing residual distortion errors.

In the fully balanced Double Shot architecture, the left and right channels each receive a dedicated DAC board to reduce interchannel crosstalk. Digital playback is complemented by an MM phono stage fitted with ETI Research Silver RCA sockets, Bluetooth aptX connectivity and a dedicated headphone output.

A defining feature of the Carbon Series is its 9 mm-thick solid carbon-fibre outer casework. The favourable vibration-damping properties of carbon fibre reduce the influence of mechanical disturbance on the sensitive audio circuitry.

The casework also helps reduce the ingress of radio-frequency and electromagnetic interference into the amplifier. This is particularly important around the preamplifier and phono circuits that handle low-level analogue signals.

The carbon-fibre outer casework is complemented by an 8 mm-thick black anodised aluminium front panel. This mechanical construction protects the sensitive internal components, enhances durability and creates the consistent visual identity of the Carbon Series.

The upgraded power supply of the Carbon Series uses premium Mundorf capacitors. These high-quality components support the stable power delivery required by the high-output GaN FET power stage and the consistent operation of both amplifier channels.

The audio circuitry is mounted on an inverted printed circuit board. This structural arrangement reduces the influence of mechanical vibration and resonance on the audio circuitry.

The signal-conducting elements in the Carbon Double Shot 400’s ETI Research Kryo speaker binding posts are made from silver-plated tellurium copper, combining high conductivity with mechanical strength and durability. The CNC-machined conductor body is designed to keep resistance, inductance and capacitance low while providing a stable, low-loss connection for high speaker currents.

The connectors undergo a controlled cryogenic treatment at extremely low temperatures to stabilise the material structure and reduce internal stresses. The brass housing and polymer clamping assembly provide mechanical damping, protection against electromagnetic and radio-frequency interference, and even clamping pressure; the binding posts accept banana plugs, spade connectors and bare speaker cable.

The enclosure rests on IsoAcoustics Gaia IV isolation feet. These mechanically decouple the amplifier from its equipment rack or furniture and reduce the transmission of environmental vibration into the chassis and internal circuitry.

Weighing 16.1 kg, the amplifier measures 440 mm wide, 415 mm deep and 130 mm high. Its wide, low-profile enclosure provides stable placement, while the carbon-fibre casework and black aluminium front panel reflect the technical construction in its exterior design.