{"product_id":"fiio-class-a-headphone-amplifier-and-preamplifier","title":"FiiO Class A Headphone Amplifier and Preamplifier","description":"\u003ch1\u003e\u003cstrong\u003e4,000mW balanced headphone amplifier\u003c\/strong\u003e\u003c\/h1\u003e\n\u003cp\u003eThe FiiO CLASS A is a fully discrete Class-A desktop headphone amplifier and preamplifier built around a fully-balanced differential architecture. It combines up to 4,000mW + 4,000mW of balanced output power at 32Ω with five gain levels, independent bass and treble adjustment, balanced and single-ended connectivity, and a substantial linear power supply built around a custom 60W toroidal transformer.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eFully-discrete Class-A amplification\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eThe amplification stage uses individually -elected transistors, resistors, and capacitors rather than an integrated power amplifier. FiiO pairs Toshiba twin transistors and complementary pairs with Sanken audio transistors, with quiescent current manually calibrated. The circuit is designed for the continuous-current operating characteristics of Class A amplification while supporting precise control across a wide range of headphone loads.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eFully-balanced high-power architecture\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eA fully-balanced differential circuit provides separate positive and negative signal paths for each channel. The CLASS A delivers up to 4,000mW + 4,000mW into 32Ω through its balanced headphone output, giving it substantial output capability for demanding over-ear headphones. A built-in DC servo circuit continuously monitors and corrects output DC offset to help maintain stable operation and protect connected headphones.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eLinear power supply with 20,000μF capacitance\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eA custom 60W toroidal transformer feeds a split regulated power supply designed for the high quiescent-current demands of the Class A circuit. The transformer uses a continuous silicon-steel strip core, copper windings, magnetic shielding, and a resettable thermal switch. A 20,000μF capacitor reservoir with Nichicon audio capacitors provides stored energy for transient demands while helping reduce power-supply ripple.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eFive gain levels and tone control\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eFive selectable gain settings — Low, Medium, High, Super High, and Ultra High — provide a broad adjustment range for headphones with different sensitivities and impedances. Independent bass and treble controls offer ±10dB of adjustment, allowing low- and high-frequency balance to be tailored without changing source components.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eFlexible headphone and line connectivity\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eThree front-panel headphone outputs cover 1\/4 in. (6.35mm) single-ended, 4.4mm balanced, and 4-pin XLR balanced connections. Analog inputs include 1\/8 in. (3.5mm) single-ended, RCA, 4.4mm balanced, and XLR balanced. RCA and XLR line outputs allow the CLASS A to operate as a preamplifier for downstream power amplifiers or active speakers.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eDesktop system integration\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003e12V trigger input and output allow compatible components to coordinate power control across a desktop audio system. A USB-C port is provided for firmware updates, while front-panel indicators show output mode and mute status. The illuminated volume control supports mute, output switching, and selectable indicator-light behavior directly from the knob.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eProtection for long-term operation\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eMultiple protection circuits monitor operating conditions throughout the amplifier. These include DC output protection, power-input overcurrent protection, headphone-amplifier temperature protection, overvoltage protection, output-overload detection, and transformer thermal protection.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eProduct highlights\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eFully discrete Class A headphone amplifier and preamplifier\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eFully-balanced differential amplification architecture\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eUp to 4,000mW + 4,000mW balanced output at 32Ω\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eFive selectable gain levels\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e±10dB independent bass and treble adjustment\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eCustom 60W toroidal transformer\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e20,000μF capacitor reservoir\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eToshiba twin and complementary audio transistors\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eSanken audio transistors\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eDC servo output control\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e1\/4 in. (6.35mm), 4.4mm, and 4-pin XLR headphone outputs\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eRCA and XLR preamplifier outputs\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e12V trigger input and output\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eUSB-C firmware update port\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eSpecs\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eColor: Black or silver\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eDimensions: About 8.39 x 9.41 x 2.64 in. (213 x 239 x 67mm)\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eWeight: About 7.72 lb (3.5kg)\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003ePower input: AC 100–120V \/ 220–240V, 50\/60Hz\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eMain controller: ESP32-S3\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eAmplifier transistors: 16 Toshiba twin matched-pair audio\u003c\/li\u003e\n\u003cli\u003etransistors and 8 Sanken Electric audio transistors\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eLinear power supply: 60W custom toroidal transformer\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eRCA \/ 1\/8 in. input impedance: 5kΩ\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eXLR \/ 4.4mm input impedance: 8kΩ\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eFrequency response: 20Hz–95kHz, attenuation \u0026lt;3dB\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eSNR: ≥126dB A-weighted\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eNoise floor: \u0026lt;3.7μV A-weighted\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eTHD+N: \u0026lt;0.00046% at XLR output, 1kHz, -2dBV into 10kΩ\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eBalanced output at 16Ω: Up to 2,000mW + 2,000mW\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eBalanced output at 32Ω: Up to 4,000mW + 4,000mW\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eBalanced output at 300Ω: Up to 1,360mW + 1,360mW\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e1\/4 in. single-ended output at 16Ω: Up to 2,000mW + 2,000mW\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e1\/4 in. single-ended output at 32Ω: Up to 2,850mW + 2,850mW\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e1\/4 in. single-ended output at 300Ω: Up to 350mW + 350mW\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eWhat’s included\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eFiiO CLASS A amplifier\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eDust cap\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eFuse\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eWarranty card\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eAC power cord\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eRCA cable\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eQuick start guide\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"FiiO","offers":[{"title":"Black","offer_id":48377227608300,"sku":"APS-1439-1","price":379.99,"currency_code":"USD","in_stock":true},{"title":"Silver","offer_id":48377227641068,"sku":"APS-1439-2","price":379.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0225\/2721\/3642\/files\/0039.jpg?v=1789675190","url":"https:\/\/apos.audio\/products\/fiio-class-a-headphone-amplifier-and-preamplifier","provider":"Apos","version":"1.0","type":"link"}