Overview

North Flat Japan (North Flat Japan Co., Ltd.) lists the FX-AUDIO D802J++ as a full-digital amplifier, reportedly adopting the STMicroelectronics STA326 chip per published materials. Aimed at desktop use, it is indicated to provide multiple digital inputs and an analog input, along with tone control functions. Specific configurations may vary by sales period and documentation.

Scientific Validity

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As of writing, we could not locate official measured data such as THD, SNR, output impedance, and damping factor for the product. While specifications are described in general terms, the absence of implementation-level measurements limits scientific evaluation.

Technology Level

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The STA326 is a general-purpose chip, and we did not find public descriptions of proprietary algorithms or measurement-improvement measures unique to this model. The implementation appears focused on basic functionality; originality cannot be firmly assessed from open information.

Cost-Performance

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Cost-performance receives an average evaluation. The D802J++ market price of 111 USD, and the AIYIMA A07 Premium (featuring TPA3255, SNR 103dB, THD 0.05%) at 73 USD. Calculation: 73 USD ÷ 111 USD = 0.66, rounded to 0.7. The A07 Premium discloses clear measurement data and adopts a higher-performance chip, offering superior technical transparency, though the price difference is not substantial.

Reliability & Support

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Domestic support is generally identifiable from public information. However, due to limited disclosure of detailed technical specifications and measurement data, we conservatively evaluate predictability for advanced troubleshooting. Warranty and repair appear within common ranges, subject to the latest official information.

Rationality of Design Philosophy

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Given the limited scope of measurement disclosure, transparency of performance verification appears constrained, resulting in a cautious score. Utilizing off-the-shelf chips is rational, yet the presentation of validation details appears limited in public materials.

Advice

When considering this model, check whether the maker discloses measurement data, confirm required features (input types, tone control) against your setup, and review support arrangements. Priorities will differ depending on the weight placed on domestic support versus transparency of measurements. Always verify the latest official documentation.

(This article is based on publicly available information at the time of writing and may change without notice.)

(2025.8.8)