{"product_id":"fosi-audio-sk01","title":"Fosi Audio SK01","description":"\u003cp\u003eFosi Audio SK01 is a battery-powered analog headphone amplifier and preamplifier with 3.5mm line input, dual headphone jacks and adjustable three-band tone control.\u003c\/p\u003e\u003cp\u003eUp to 2400mW at 32Ω in high gain, pure bypass, loudness and a 2500mAh battery make it flexible for desktop and transportable wired listening.\u003c\/p\u003e\u003ch2\u003eWhy it stands out\u003c\/h2\u003e\u003ch3\u003eHigh-power analog headphone drive\u003c\/h3\u003e\u003cp\u003eHigh gain delivers up to 2400mW at 32Ω for a broad 16–300Ω headphone range.\u003c\/p\u003e\u003ch3\u003eThree-band tone shaping\u003c\/h3\u003e\u003cp\u003eSeparate treble, midrange and bass controls allow more precise adjustment than basic two-band designs.\u003c\/p\u003e\u003ch3\u003ePure and loudness modes\u003c\/h3\u003e\u003cp\u003eBypass removes tone processing, while loudness improves perceived bass and treble at low listening levels.\u003c\/p\u003e\u003ch3\u003eHeadphone amp and preamp\u003c\/h3\u003e\u003cp\u003e3.5mm line out feeds an amplifier or powered speakers with the same volume and tone control.\u003c\/p\u003e\u003ch2\u003eBest for\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003ePowerful wired headphone listening\u003c\/li\u003e\n\u003cli\u003eAnalog sources needing portable amplification\u003c\/li\u003e\n\u003cli\u003eUsers wanting three-band tone control\u003c\/li\u003e\n\u003cli\u003ePreamp use with powered speakers or a power amplifier\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eNot ideal for\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eUSB digital audio or DAC conversion\u003c\/li\u003e\n\u003cli\u003eBluetooth wireless playback\u003c\/li\u003e\n\u003cli\u003eBalanced headphone connections\u003c\/li\u003e\n\u003c\/ul\u003e\u003cdiv class=\"emiuzek-product-content-images\" style=\"grid-column:1 \/ -1;width:100%;max-width:1100px;margin:8px auto 32px;\"\u003e\n\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0604\/7422\/8829\/files\/FosiAudioSK0102_9372ec89-77fe-4bdc-995b-f254ef8d72fc.webp?v=1758520126\" alt=\"Fosi Audio SK01 high-power headphone amplifier and three-band tone control\" loading=\"lazy\" style=\"display:block;width:100%;max-width:1100px;height:auto;margin:0 auto 24px;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0604\/7422\/8829\/files\/FosiAudioSK01-03_dd374eb7-e8a5-4fc6-9320-b2354753a484.webp?v=1758524322\" alt=\"Fosi Audio SK01 line input, pre-out, 3.5mm and 6.35mm headphone connections\" loading=\"lazy\" style=\"display:block;width:100%;max-width:1100px;height:auto;margin:0 auto 24px;\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0604\/7422\/8829\/files\/FosiAudioSK01-04_28da0aac-7481-4e2e-8c91-eb44ed44ca7c.webp?v=1758524322\" alt=\"Fosi Audio SK01 portable headphone amplifier and desktop preamplifier scenarios\" loading=\"lazy\" style=\"display:block;width:100%;max-width:1100px;height:auto;margin:0 auto 24px;\"\u003e\n\u003c\/div\u003e\u003ch2\u003eEMiUZEK Buying Notes\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eSK01 is analog only; USB-C is for charging and does not carry audio data.\u003c\/li\u003e\n\u003cli\u003eIt cannot drive passive speakers directly; line out must feed an amplifier.\u003c\/li\u003e\n\u003cli\u003eHigh gain can become very loud—start at minimum volume before wearing headphones.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eFrequently asked questions\u003c\/h2\u003e\u003ch3\u003eDoes USB-C carry audio?\u003c\/h3\u003e\u003cp\u003eNo. USB-C is for 5V charging only.\u003c\/p\u003e\u003ch3\u003eCan it work as a preamp?\u003c\/h3\u003e\u003cp\u003eYes. Use 3.5mm line out into an amplifier or powered speakers.\u003c\/p\u003e\u003ch3\u003eCan it drive passive speakers?\u003c\/h3\u003e\u003cp\u003eNo. A separate power amplifier is required.\u003c\/p\u003e\u003ch3\u003eWhat headphones are supported?\u003c\/h3\u003e\u003cp\u003eFosi specifies 16–300Ω.\u003c\/p\u003e\u003ch3\u003eCan tone controls be bypassed?\u003c\/h3\u003e\u003cp\u003eYes. PURE mode bypasses the tone circuit.\u003c\/p\u003e\u003ch3\u003eHow long does the battery last?\u003c\/h3\u003e\u003cp\u003eFosi states up to about six hours, depending on use and load.\u003c\/p\u003e\u003ch2\u003eHOW TO CONNECT\u003c\/h2\u003e\u003ch3\u003ePortable headphones\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eSource:\u003c\/strong\u003e Phone, DAP or dongle DAC\u003cbr\u003e\u003cstrong\u003eConnection:\u003c\/strong\u003e 3.5mm line in\u003cbr\u003e\u003cstrong\u003eOutput:\u003c\/strong\u003e 3.5mm or 6.35mm headphone\u003cbr\u003e\u003cstrong\u003eTarget:\u003c\/strong\u003e Wired headphones\u003cbr\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e USB-C is not an audio input.\u003c\/p\u003e\u003ch3\u003eDesktop preamp\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eSource:\u003c\/strong\u003e DAC or streamer\u003cbr\u003e\u003cstrong\u003eConnection:\u003c\/strong\u003e 3.5mm line in\u003cbr\u003e\u003cstrong\u003eOutput:\u003c\/strong\u003e 3.5mm line out\u003cbr\u003e\u003cstrong\u003eTarget:\u003c\/strong\u003e Power amplifier or powered speakers\u003cbr\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e SK01 controls level and tone.\u003c\/p\u003e\u003ch3\u003eHigh-impedance headphones\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eSource:\u003c\/strong\u003e Line-level DAC\u003cbr\u003e\u003cstrong\u003eConnection:\u003c\/strong\u003e 3.5mm line in\u003cbr\u003e\u003cstrong\u003eOutput:\u003c\/strong\u003e 6.35mm headphone\u003cbr\u003e\u003cstrong\u003eTarget:\u003c\/strong\u003e 16–300Ω headphones\u003cbr\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e Choose gain carefully and start low.\u003c\/p\u003e\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\u003ch3\u003eAudio performance\u003c\/h3\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eFeature\u003c\/th\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eHigh \/ low gain output\u003c\/td\u003e\n\u003ctd\u003e2400mW \/ 300mW at 32Ω\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHeadphone impedance\u003c\/td\u003e\n\u003ctd\u003e16–300Ω\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSNR\u003c\/td\u003e\n\u003ctd\u003e108dB\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTHD\u003c\/td\u003e\n\u003ctd\u003e≤0.001% at 1kHz \/ 770mV\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFrequency response\u003c\/td\u003e\n\u003ctd\u003e20Hz–20kHz (±0.05dB)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNoise floor \/ Crosstalk\u003c\/td\u003e\n\u003ctd\u003e20μV \/ 83dB\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eConnections and power\u003c\/h3\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eFeature\u003c\/th\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eInput\u003c\/td\u003e\n\u003ctd\u003e3.5mm line in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOutputs\u003c\/td\u003e\n\u003ctd\u003e3.5mm line out; 3.5mm and 6.35mm headphones\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTone adjustment\u003c\/td\u003e\n\u003ctd\u003eTreble ±8dB; mid ±10dB; bass ±11dB\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBattery\u003c\/td\u003e\n\u003ctd\u003e2500mAh\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCharging\u003c\/td\u003e\n\u003ctd\u003eDC 5V USB-C; power only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch2\u003eRecommended System Setup\u003c\/h2\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eSetup\u003c\/th\u003e\n\u003cth\u003eConnection\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003ePortable\u003c\/td\u003e\n\u003ctd\u003ePhone\/DAP → SK01 → Headphones\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDesktop\u003c\/td\u003e\n\u003ctd\u003eDAC → SK01 → Headphones\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePreamp\u003c\/td\u003e\n\u003ctd\u003eSource → SK01 line out → Power amplifier\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch2\u003eAdditional Product Content\u003c\/h2\u003e\u003ch3\u003eFosi Audio product comparison\u003c\/h3\u003e\u003cp\u003eCompare the models by the differences that most affect system matching and everyday use.\u003c\/p\u003e\u003cdiv style=\"max-width:100%;overflow-x:auto;-webkit-overflow-scrolling:touch;\"\u003e\u003ctable style=\"min-width:860px;\"\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth style=\"min-width:150px;\"\u003eFeature\u003c\/th\u003e\n\u003cth style=\"min-width:190px;\"\u003eSK01\u003c\/th\u003e\n\u003cth style=\"min-width:190px;\"\u003eSK02\u003c\/th\u003e\n\u003cth style=\"min-width:190px;\"\u003eP3\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eProduct position\u003c\/th\u003e\n\u003ctd\u003eAnalog headphone amp \/ preamp\u003c\/td\u003e\n\u003ctd\u003eUSB\/optical DAC headphone amp\u003c\/td\u003e\n\u003ctd\u003eTube preamp \/ headphone amp\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eDigital DAC\u003c\/th\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003ctd\u003eYes, ES9038Q2M\u003c\/td\u003e\n\u003ctd\u003eBluetooth input only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMain inputs\u003c\/th\u003e\n\u003ctd\u003e3.5mm line\u003c\/td\u003e\n\u003ctd\u003eUSB, optical\u003c\/td\u003e\n\u003ctd\u003eBluetooth, RCA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eHeadphone outputs\u003c\/th\u003e\n\u003ctd\u003e3.5mm, 6.35mm\u003c\/td\u003e\n\u003ctd\u003e3.5mm, 4.4mm\u003c\/td\u003e\n\u003ctd\u003e3.5mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMaximum output at 32Ω\u003c\/th\u003e\n\u003ctd\u003e2400mW high gain\u003c\/td\u003e\n\u003ctd\u003e755mW via 4.4mm\u003c\/td\u003e\n\u003ctd\u003e150mW\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eBalanced headphone output\u003c\/th\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003ctd\u003e4.4mm\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eTone controls\u003c\/th\u003e\n\u003ctd\u003eTreble, mid, bass\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003ctd\u003eBass, treble\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eBattery operation\u003c\/th\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003ctd\u003eNo\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eLine \/ pre-out\u003c\/th\u003e\n\u003ctd\u003e3.5mm\u003c\/td\u003e\n\u003ctd\u003e3.5mm line \/ optical\u003c\/td\u003e\n\u003ctd\u003eRCA, AUX\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eBest use\u003c\/th\u003e\n\u003ctd\u003ePowerful analog portable amp\u003c\/td\u003e\n\u003ctd\u003eHi-res desktop DAC\/amp\u003c\/td\u003e\n\u003ctd\u003eTube Bluetooth preamp\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003c\/div\u003e","brand":"Fosi Audio","offers":[{"title":"Black \/ US","offer_id":43678059266141,"sku":"Fosi-Audio-SK01-Black-US","price":130.0,"currency_code":"BRL","in_stock":true},{"title":"Black \/ EU","offer_id":43678059298909,"sku":"Fosi-Audio-SK01-Black-EU","price":402.0,"currency_code":"BRL","in_stock":true},{"title":"Black \/ UK","offer_id":43678059331677,"sku":"Fosi-Audio-SK01-Black-UK","price":402.0,"currency_code":"BRL","in_stock":true},{"title":"Black \/ AU","offer_id":43678059364445,"sku":"Fosi-Audio-SK01-Black-AU","price":402.0,"currency_code":"BRL","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0604\/7422\/8829\/files\/Fosi_Audio_SK01_7a680de3-2f06-4c5e-909b-3a10273a7874.webp?v=1785380488","url":"https:\/\/emiuzek.com\/pt-br\/products\/fosi-audio-sk01","provider":"EMiUZEK","version":"1.0","type":"link"}