{"product_id":"singxer-sa-2-fully-balanced-class-a-headphone-amplifier-preamplifier-with-xlr-balanced-6-35mm-and-4-4mm-output","title":"Singxer SA-2 Fully Balanced Class-A Headphone Amplifier Preamplifier with XLR Balanced, 6.35mm and 4.4mm Output","description":"\u003cdiv\u003e\u003cb\u003eDescription:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003eThe newly designed SA-2 is a high-performance fully balanced, fully discrete Class-A headphone amplifier and preamplifier. As the next-generation model replacing the SA-1, the SA-2 retains a similar chassis design, while the internal circuit layout has been completely reworked. By increasing the power supply voltage and reducing output impedance, the SA-2 delivers a substantial improvement in output power and overall driving capability.\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003eThe SA-2 features a true four-channel, fully independent, fully discrete Class-A amplifier topology. It employs a purely analog amplification path and purely analog control, with no digital control circuitry involved. This design eliminates EMI interference introduced by digital systems, ensuring faithful reproduction of the natural, analog character of music.\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003eThe amplification stage is based on our self-developed Class-A architecture. The differential input stage uses original ultra-low-noise audio-grade transistors for ROHM in an SMD matched-pair configuration to ensure excellent device consistency. Other stages utilize high-linearity audio-grade transistors to achieve superior overall performance. The power supply section is built around high-current, ultra-low-noise LDO regulators to provide a clean and stable power foundation.\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003eThe output stage adopts a multi-stage current amplification design similar to that of high-power speaker amplifiers. Each channel uses two pairs of original medium-power output transistors (for ON Semiconductor) with a driving current capability of up to 4A in parallel configuration. This ensures extremely low output impedance and powerful drive capability, allowing the SA-2 to remain composed and controlled even during large dynamic passages.\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003eComprehensive protection mechanisms are built in, including over-current, overload, over-temperature, short-circuit, and DC protection. A power-on delay is implemented, and the output relay is immediately disconnected during power-off to fully protect connected headphones and downstream equipment.\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003eKey Improvements:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e1. Output power has been increased from 5.5W at 32Ω (SA-1) to 10W at 32Ω, with a maximum output of 15W at a 20Ω load; supports headphones with a minimum impedance of 8Ω.\u003c\/div\u003e\n\u003cdiv\u003e2. Circuitry has been optimized to maintain ultra-low distortion even at high output power levels.\u003c\/div\u003e\n\u003cdiv\u003e3. A more efficient thermal management design employing a copper block combined with an aluminum alloy heatsink.\u003c\/div\u003e\n\u003cdiv\u003e4. Reduced output impedance at the balanced headphone output, improving current delivery and providing stronger driving capability.\u003c\/div\u003e\n\u003cdiv\u003e5. Optimized PCB layout with adjusted DC bias architecture, the addition of a DC servo circuit, and inclusion of a GND\/LIFT mode switch.\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003eAdvantages:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e* Supports global AC input voltage from 100V to 240V with no manual switching required. The main unit is identical for European, US, and UK versions; only the supplied power cord differs.\u003c\/div\u003e\n\u003cdiv\u003e* Ultra-low distortion performance: THD+N of –125dB at 1kHz (A-weighted) in preamplifier mode with 5.2 V RMS output. In balanced headphone amplifier mode, THD+N reaches –117dB at 1kHz with a 32-ohm load at 8W output.\u003c\/div\u003e\n\u003cdiv\u003e* Ultra-low noise performance: at low gain, the noise floor is as low as 500nV RMS (A-weighted, 20Hz–22kHz), measured after LNA amplification. Direct measurement using an APX555 analyzer shows a noise level of 830nV RMS.\u003c\/div\u003e\n\u003cdiv\u003e* Exceptional signal-to-noise ratio and dynamic range, with SNR\/DNR exceeding 146dB (A-weighted).\u003c\/div\u003e\n\u003cdiv\u003e* Wideband frequency response from 20Hz to 80kHz with ±0.1dB deviation.\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003ePacking List:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e* 1 × Main Unit\u003c\/div\u003e\n\u003cdiv\u003e* 1 × Power Cable\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003eMultifunctional and Versatile Design:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e1. Supports both single-ended and balanced inputs, freely switchable to accommodate different source devices.\u003c\/div\u003e\n\u003cdiv\u003e2. Supports multiple output interfaces: XLR 4-pin true balanced, 6.35mm single-ended, and 4.4mm balanced. Also supports both single-ended and balanced outputs in preamplifier mode.\u003c\/div\u003e\n\u003cdiv\u003e3. It supports high and low gain design. At low gain, it can easily connect to various in-ear earphones, ultra-sensitive earphones, etc. (while still maintaining an inaudible background noise); at high gain, it can drive various high-end headphones, including various high-impedance dynamic drivers, low-impedance planar magnetic drivers, and even ultra-low-impedance headphones like the KK.\u003c\/div\u003e\n\u003cdiv\u003e4. It supports selectable high and low output impedance. High impedance is optimized for high-impedance headphones. Low impedance provides high current drive for low-impedance headphones. Freely switchable, allowing users to choose between a powerful, well-controlled sound or a more relaxed, smooth analog-style presentation.\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-01.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-02.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-03.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-04.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-05.jpg\" style=\"width: 1200px;\"\u003e\u003cbr\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003eSA-2 Class A Mode:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e* Balanced 16Ω load: below 400mW;\u003c\/div\u003e\n\u003cdiv\u003e* Balanced 32Ω load: below 800mW;\u003c\/div\u003e\n\u003cdiv\u003e* Balanced 64Ω load: below 1600mW;\u003c\/div\u003e\n\u003cdiv\u003e* Balanced loads above 64Ω: almost all output power operates in Class A.\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003eSA-2 Gains:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e1. Single-ended input, single-ended output: Low gain: 0dB; high gain: 12.8dB;\u003c\/div\u003e\n\u003cdiv\u003e2. Single-ended input, balanced output: Low gain: 6dB; high gain: 18.8dB;\u003c\/div\u003e\n\u003cdiv\u003e3. Balanced input, single-ended output: Low gain: −6dB; high gain: 6.8dB;\u003c\/div\u003e\n\u003cdiv\u003e4. Balanced input, balanced output: Low gain: 0dB; high gain: 12.8dB;\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003eInput Impedance:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e* Single-ended: 33kΩ; balanced: 20kΩ;\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003eInput Sensitivity:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e* Balanced input, balanced output: High gain: 4.2V RMS; Low gain: 18V RMS;\u003c\/div\u003e\n\u003cdiv\u003e* Single-ended input, balanced output: Low gain: 9V RMS; High gain: 2.1V RMS;\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003eHeadphone Amplifier Output Impedance:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e* LOW-Z switch: low-impedance mode;\u003c\/div\u003e\n\u003cdiv\u003e* HI-Z switch: high-impedance mode;\u003c\/div\u003e\n\u003cdiv\u003e* Low-impedance mode: Balanced: 0.15Ω; single-ended: 1.1Ω;\u003c\/div\u003e\n\u003cdiv\u003e* High-impedance mode: Balanced: 10Ω; single-ended: 11Ω;\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003ePreamp Output:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e* Single-ended output impedance: 75Ω; balanced output impedance: 150Ω.\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003eUsage Recommendations and Notes:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e1. The SA-2 is designed around a fully balanced architecture and optimized for balanced operation. For best performance, the recommended configuration is balanced input with balanced output. The second-best option is single-ended input with balanced output.\u003c\/div\u003e\n\u003cdiv\u003e2. If single-ended operation is required, it is recommended to use single-ended input.\u003c\/div\u003e\n\u003cdiv\u003e3. For high-sensitivity headphones such as in-ear earphones, high-gain mode is not recommended.\u003c\/div\u003e\n\u003cdiv\u003e4. The ground switch is set to GND mode by default. If a ground loop noise is present, switch to LIFT mode (floating ground) to eliminate the noise.\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003eUltra-Low Distortion\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003eThe images below show performance measurements of the test unit using an APX555 audio analyzer:\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-06.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-07.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-08.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-09.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-10.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-11.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-12.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-13.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-14.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-15.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003eThe following tests were conducted with balanced headphone output and a 32Ω load:\u003c\/div\u003e\n\u003cdiv\u003e\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-16.jpg\" style=\"width: 1200px;\"\u003e\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cimg src=\"https:\/\/www.comseek.com\/image\/catalog\/100503\/100503-17.jpg\" style=\"width: 1200px;\"\u003e\u003cbr\u003e\u003cbr\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003eChassis Dimensions:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e* Chassis dimensions (L × W × H): 234mm × 170mm × 46mm, excluding the height of the feet and the protruding rear connectors\u003c\/div\u003e\n\u003cdiv\u003e* Net weight of main unit: approximately 1.8kg\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003ePackaging Details:\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e* Packaging size: 350mm × 230mm × 110mm\u003c\/div\u003e\n\u003cdiv\u003e* Weight: approximately 2.3kg\u003c\/div\u003e","brand":"Singxer","offers":[{"title":"Default Title","offer_id":41028840816689,"sku":"100503","price":632.39,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0578\/4790\/6353\/files\/1768266160-9.jpg?v=1780349878","url":"https:\/\/www.thanksbuyer.com\/ru\/products\/singxer-sa-2-fully-balanced-class-a-headphone-amplifier-preamplifier-with-xlr-balanced-6-35mm-and-4-4mm-output","provider":"Thanksbuyer Online,SDR Radio, Testers and Measurement devices, Astronomy products,  Audio Amplifer and Decoders","version":"1.0","type":"link"}