FiiO, DAC changed to ESS, evolved core DAP "M11 Plus ESS"

Photo: Impress Watch

Emirai changed the DAC chip of FiiO's core digital audio player "M11 Plus LTD" from that of Asahi Kasei Electronics to "ES9068AS" made by ESS, and realized further performance improvement, the successor model "M11 Plus ESS". Will be released on February 25th. The price is an open price, and the estimated retail price is around 97,900 yen. [See another image related to this article] The DAC chip of the limited production model "M11 Plus LTD" equipped with the "AK4497EQ" has been replaced with the ESS "ES9068AS" to further improve the specifications. Not only that, the D / A conversion section itself has been brushed up with the change of the DAC chip. In addition to changing the operational amplifier used for the low-pass filter from "OPA1662" to "OPA927" according to the characteristics of the chip, the DAC chip is in charge of the volume adjustment function that was previously performed by the volume adjustment IC. So, the volume IC circuit is abolished. Further improvement of characteristics has been realized. As a result, the SN ratio at 2.5mm balanced output has improved by up to 5.5dB from 120.5dB to 126dB, and THD + N, which represents the distortion factor, has improved from less than 0.00146% to 0.00085% or less (at 1kHz / 32Ω). Furthermore, the maximum output at 2.5mm balanced output has been enhanced from 588mW to 660mW (32Ω / THD + N <1%), while the continuous playback time has increased from 10 hours to 14 hours thanks to the low power consumption DAC chip. It is growing. Headphone output is equipped with 3.5mm single end and 2.5mm / 4.4mm balanced output. Furthermore, in addition to the conventional 3.5 mm line output function, a 4.4 mm balanced line output function is also installed (also used as a 4.4 mm balanced headphone output terminal). At the time of line output, the headphone amplifier section is automatically bypassed, and a higher purity audio signal can be output. Balanced line connection with a portable headphone amplifier that supports balanced connection is now possible. The headphone amplifier circuit uses the THX AAA Frontier series "THX AAA-78 amplifier". It features THX's patented feed-forward correction technology and a design method that pursues neutral sound quality. Brings a sound like that. " Compared to a general headphone amplifier circuit, the THX AAA circuit can achieve high output with high efficiency, lower noise level, and lower distortion even when the same power supply unit is used. The headphone amplifier section of the M11 Plus ESS has evolved to the second generation based on the AAA-78 circuit. By strengthening the driving force that realizes richness of low-frequency scale and sharp focus, "We have promoted further noise reduction so that noise is not noticeable even in IEM." The headphone output can be switched between low / medium / high gain. The volume can be adjusted in 120 steps for each gain level, allowing fine volume adjustment. Perfect volume control is possible, whether you're using high-impedance headphones or sensitive earphones. Adopting a modular circuit design method that promotes the low noise design concept and suppresses mutual interference of the board circuit by the newly designed internal layout. Each circuit module is covered with a shield cover, and the digital part and analog part are completely separated. It is assumed that mutual interference does not occur between each section and higher purity sound quality is realized. Independent power supplies are given to the low-pass filter section, small signal amplification section, and amplification expansion circuit in the previous stage, and special shield covers, custom-made high heat-resistant silica gel and graphene are used for various parts. By making full use of nickel silver heat sinks that absorb and release heat as needed, temperature control is thorough and the durability of the entire product is improved. Equipped with Qualcomm's SoC "Snapdragon 660". While having the ability to handle heavy tasks such as video playback and games, it can operate with ultra-low power consumption when playing music. Memory is 4GB, internal storage is 64G. It also has a microSD card slot that accepts cards up to 2TB. The Digital Audio Purification System (DAPS) is used for the signal processing circuit in the digital domain centered on FPGA, which is the key to digital signal processing. Digital data sent from the SoC is sent via a proprietary 4th generation FPGA equipped with FiiO's proprietary PLL technology. The DAC is treated so that it is most effective as a digital audio signal in the FPGA. In addition, DAPS also incorporates two custom-made NDK femtoclock crystal oscillators that achieve ultra-low jitter in the femtosecond class, providing a high-precision, low-jitter master clock for the entire digital audio circuit. , Achieves clean and extremely high fidelity D / A conversion. Equipped with FiiO custom Android 10. Intuitive operation is possible. Dark mode, night mode, and 3 navigation settings are available. In addition, Nai has a Pure Music mode that stops the operation of other applications and specializes in music playback to maximize sound quality, an Android mode that can also use third-party apps, a Bluetooth reception mode, and a USB DAC mode. It also supports AirPlay and DLNA. AAC is newly added as a Bluetooth transmission / reception codec. "IPhone users have more flexibility to enjoy HiFi-grade wireless audio," he said. The transmission compatible codec is SBC / AAC / aptX / aptX HD / LDAC, and the reception compatible codec is SBC / AAC / LDAC. A volume button + touch panel combined volume adjustment mechanism is mounted on the side of the housing. Space-saving, accurate adjustment by button operation or intuitive adjustment by slide operation on the touch panel is possible. When "DSD conversion mode" is used, the PCM signal is converted to DSD during the D / A conversion process and then played. You can experience a natural and clear sound with a texture different from PCM. This DSD conversion mode can also be applied to songs played by third-party apps. It also supports 8x decoding of MQA sound sources. The display is 1,440 x 720 dots and the size is 5.5 inches. The 18: 9 aspect ratio provides a great visual experience and a more comfortable grip. Equipped with a 6,000mAh battery that supports fast charging of QC2.0 / 3.0 / 4.0 and USB PD. After a full charge, continuous playback for about 14 hours and deep sleep for up to about 1,000 hours are possible. It has a USB-C terminal. The external dimensions are 136.6 x 75.7 x 17.6 mm (length x width x thickness), and the weight is 295 g. As a special accessory, a leather case "SK-M11 Plus LTD" is also available as an option.

AV Watch, Kentaro Yamazaki