FIIO K9 AKM Authorized Store Product Serial Number Headphone Amplifier Asahi Kasei AK4191EQ AK4499EX USB DAC Headphone Amplifier [Japanese / Included]

【Voltage Compatibility】 When using electrical appliances, please note that they are designed for Japanese voltage specifications (90-110V), so if you use them with a different voltage, it may cause a malfunction.

【Plug Type】 Our products use Japanese plug types (A or B type). Please use a conversion adapter if necessary.

【Important Note on Transformers and Adapters】 A transformer adjusts voltage to match your device’s requirements. A conversion adapter only changes the plug shape and does not adjust voltage. Using only a conversion adapter without a transformer may result in damage to the product.

【Liability】 We are not responsible for malfunctions or damages caused by improper use, such as operating the product without a transformer. [Equipped with AKM's flagship separate DAC system "AK4191EQ + AK4499EX"] K9 AKM uses AKM's flagship DAC "AK4191EQ + AK4499EX". This DAC system uses a separate DAC system consisting of the AK4191EQ, which handles the digital filter and delta-sigma modulation, and the AK4499EX, which handles the analog DAC. In addition to separating the completely different functions of digital processing and analog processing at the chip level, we have combined "DWA Routing Technology" that equalizes individual differences in resistance elements to improve the S/N ratio at the chip level. This is a new generation DAC system that is not only numerically improved from the previous flagship model, but also pays close attention to the expression of texture. [Equipped with the "THX-AAA 788+" headphone amplifier circuit developed jointly with THX] The K9 AKM is equipped with the "THX-AAA 788+" amplifier circuit equipped with high-quality feedforward technology that corrects the distortion that occurs during signal amplification. This circuit is an amplifier circuit jointly developed by FIIO and THX, based on the ``THX-AAA 788'' circuit, which was designed with the ideal of providing highly transparent and pure sound. By installing two of these amplifier circuits, one for each left and right channel, we are able to achieve a high output of up to 2000mW when loaded with 32Ω and 780mW when loaded with 300Ω, while maintaining low distortion. [Fully balanced design from DAC to headphone amplifier section] The K9 AKM's audio circuit has a fully balanced configuration that thoroughly inputs differential signals into circuits separated by left and right channels, from the DAC to the volume control and headphone amplifier. In addition, the audio circuit is divided into six blocks: DAC, low-pass filter, volume control, buffer amplifier, preamp, and headphone amplifier, and each block has been carefully designed to achieve a sound that combines the majesty and detailed expression typical of a stationary product. Furthermore, by separating and optimizing the layout of each main processing section on the board, harmful mutual interference is eliminated to the utmost, enabling high-quality music playback with high signal fidelity. [Equipped with XMOS's "XUF208" and two systems of ultra-high precision crystal oscillators] The K9 AKM uses XMOS's "XUF208" as the USB decoding chip. Equipped with this chip, it has decoding capabilities of up to 768kHz/32bit for PCM and up to DSD512 for DSD, and uses dual clock management technology that always selects the optimal clock for the input source to perform high-quality D/A conversion with high signal fidelity. [Clean power supply design that is the source of high sound quality] The power transformer installed inside the K9 AKM is combined with four 4700uF large capacity capacitors to provide a clean power supply to the internal audio circuit. In addition, by supplying independent power to each circuit in the digital and analog sections, power supply noise that adversely affects sound quality is suppressed, and mutual interference between each block is suppressed. In addition, each block on the circuit is kept clean by a low-noise LDO, providing the appropriate amount of boosted power to each block. This thorough power supply design achieves high S/N and deep sound image expression. [Equipped with ADC volume control function that enables fine volume adjustment] K9 AKM is equipped with ADC volume control function for volume adjustment. Unlike the analog volume method, which directly operates the variable resistor through which the music signal is applied, this method adjusts the volume by controlling the volume IC based on the AD-converted value of the amount of rotational change of the volume knob. While allowing for detailed volume adjustment in 120 steps, we succeeded in eliminating the volume difference between left and right and noise, which are problems with analog volume. [Equipped with a wealth of input and output terminals to suit all kinds of applications] The K9 AKM is equipped with a wealth of input and output terminals, so you can not only connect it to a PC, but also connect it to a variety of digital devices to enjoy a high-quality audio experience, or easily incorporate it as part of your existing audio system. [Equipped with Qualcomm's "QCC5124" and supports high-quality wireless transmission] K9 AKM is equipped with Qualcomm's Bluetooth SoC "QCC5124" and can also be used as a high-performance Bluetooth receiver that supports high-quality Bluetooth codecs such as LDAC, aptX HD, and aptX Adaptive. K9 AKM, which allows wireless connectivity that satisfies both high information content and low latency, not only allows you to enjoy music, but also provides a more immersive gaming and video experience. [UAC1.0/2.0, connection mode can be switched freely] K9 AKM supports connection with both UAC1.0 and 2.0 standards, making it compatible with various devices including home game consoles. Switching the connection mode can be easily done from the "FIIO Control" app distributed for smartphones. [More detailed settings are possible by linking with the FIIO control app] By linking the FIIO control app distributed for smartphones with K9 AKM, it is possible to configure digital filters, various equalizer functions, channel balance changes, LED display settings, etc. to suit each user's preferences. *Equalizer function is only valid when connected via Bluetooth. The K9 AKM is a high-performance model that is equipped with the flagship audio DAC chip system "AK4191EQ + AK4499EX" manufactured by Asahi Kasei Microdevices (AKM), and uses the same design as the top-of-the-line model K9 Pro ESS for audio circuitry, board layout, etc.