FIIO K7 Compact Desktop Headphone Amplifier with USB DAC and Dual Built-in THX-AAA 788+

Dual AKM DAC Chips: The K7 features the latest AK4493SEQ DAC chips, a redesign of the predecessor AK4493EQ by Asahi Kasei Microdevices (AKM) using current high-quality sound technology. Designed based on advanced VELVET SOUND technology, the AK4493SEQ delivers rich information, a sense of speed, and realistic spatial expression while effectively reducing power consumption through optimized impedance. Furthermore, a revised noise design significantly improves perceived noise beyond catalog specifications. Specified S/N ratios of up to 128dB and THD+N of -115dB deliver superior analog performance. Fully balanced design from DAC to headphone amplifier: The K7's audio circuitry is based on the same architecture as the top-of-the-line K9 Pro ESS model, and is a fully balanced circuit consisting of six blocks: DAC, low-pass filter, volume control, buffer amplifier, preamplifier, and headphone amplifier. By thoroughly using differential signal inputs to each block separated by left and right channels, mutual interference that adversely affects sound quality is minimized, enabling higher-level music reproduction with greater fidelity to the signal. Equipped with two "THX-AAA 788+" headphone amplifier circuits jointly developed by FiiO and THX: The K7 is equipped with the same "THX-AAA 788+" amplifier circuit as the K9 Pro ESS, FiiO's flagship desktop headphone amplifier. This amplifier circuit was jointly developed by FiiO and THX based on the "THX-AAA 788" circuit to provide ideal detail and dynamics for all headphone playback, from high to low efficiency. The K7 features a fully balanced configuration with two amplifiers, one per left and one per channel, delivering a maximum output of 2000mW at 32Ω load and 560mW at 300Ω load. XMOS XUF208 for PCM 384kHz/32bit and DSD256 Playback: The K7 uses the XMOS XUF208 USB decoding chip, which provides PCM decoding up to 384kHz/32bit and DSD decoding up to DSD256 (Native) and DSD128 (DoP). Dual Clock Management technology ensures high-quality D/A conversion by constantly selecting the optimal clock for the input source. Clean independent power supply circuit design: To suppress power supply noise that can adversely affect sound quality, the K7 uses a power supply circuit design that provides independent power to each circuit block. The power supplied from the 12V external switching power supply is kept clean by low-noise LDOs for each block, and is then adjusted to the appropriate level before being supplied to the components. ADC volume control function for precise volume adjustment: The K7 employs an ADC volume control function for volume adjustment. Unlike analog volume systems that directly operate a variable resistor through which a music signal is passed, this system controls the volume IC based on the value obtained by converting the amount of volume change caused by the volume knob's rotation into an analog-to-digital conversion. This allows for precise volume adjustment in 112 steps while eliminating the left-right volume difference and noise that are problems with analog volume controls. Two-level hardware gain adjustment: The K7's hardware gain can be adjusted to two levels, High and Low, by operating the GAIN switch on the front of the unit. By adjusting the gain to match the efficiency of the connected headphones, you can always enjoy music at a comfortable volume level. Versatile inputs and outputs allow the K7 to function as the center of your audio system: It supports digital inputs via USB, RCA coaxial, and rectangular optical connectors, analog inputs and outputs via RCA connectors, and single-ended and balanced outputs via a 6.35mm headphone jack and a 4.4mm jack. In addition to connecting to a PC, you can connect various digital devices to enjoy music with high-quality balanced connections, or easily integrate it into your existing audio system. Use the INPUT button on the front panel to switch between inputs. When you press the button, the indicator lights up in various colors to indicate the input selection. Use the OUTPUT switch to switch between three output modes. In addition to enjoying music with headphones, you can select the appropriate output mode for connecting to active speakers or as a pure DAC to an external amplifier. Equipped with RGB indicator lights that combine function and design: The K7's RGB indicator lights have been further improved from the K5 Pro ESS, allowing it to display not only a single color but also a mixture of multiple colors. The K7's unique and vibrant colors shine in response to power on/off and input switching, making it a visually striking presence on your desk. Elegant and simple design: The K7's chassis is made from highly rigid aluminum alloy, assembled using CNC-machined components. Its compact size—55mm high and less than one-third the width of an A4 sheet—allows for a neat and tidy installation on your desk. The simple, modern design blends seamlessly into any interior. The K7 is a compact desktop USB DAC/headphone amplifier the same size as the K5 Pro ESS, but it features AKM's latest DAC chip, the AK4493SEQ, in a dual configuration, with one chip operating on each channel. The audio circuit shares the same fully balanced design as the flagship K9 Pro ESS model. This latest model supports balanced headphone connections, a popular request from users. The headphone amplifier circuit also uses the same THX-AAA 788+ technology as the K9 Pro ESS, accurately reproducing the musical details contained in the signal without compromising them, while delivering an astounding 2000mW of driving power from its compact housing.