{"product_id":"fosi-audio-gr70-tube-headphone-amp","title":"Fosi Audio GR70","description":"\u003cp\u003eFosi Audio GR70 is a Class-A tube headphone amplifier and RCA preamplifier for analog desktop and HiFi systems.\u003c\/p\u003e\u003cp\u003eA two-stage four-tube circuit, dual headphone outputs, selectable impedance modes and tone controls provide warm analog listening for headphones or downstream amplifiers.\u003c\/p\u003e\u003ch2\u003eWhy it stands out\u003c\/h2\u003e\u003ch3\u003ePure tube amplification\u003c\/h3\u003e\u003cp\u003eTwo 5654W and two 6Ж4\/6Ж8 tubes form a two-stage analog amplification path.\u003c\/p\u003e\u003ch3\u003eHeadphone and preamp functions\u003c\/h3\u003e\u003cp\u003eUse 3.5mm or 6.35mm headphones, or connect the RCA output to powered speakers or a power amplifier.\u003c\/p\u003e\u003ch3\u003eSelectable impedance modes\u003c\/h3\u003e\u003cp\u003eLow and high settings support headphones from 16Ω to 300Ω.\u003c\/p\u003e\u003ch3\u003eDirect analog tone control\u003c\/h3\u003e\u003cp\u003eFront-panel bass, treble and volume adjustment simplify sound tuning without software.\u003c\/p\u003e\u003ch2\u003eBest for\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eAnalog headphone listening\u003c\/li\u003e\n\u003cli\u003eHigh-impedance and conventional full-size headphones\u003c\/li\u003e\n\u003cli\u003eAdding tube character before a power amplifier\u003c\/li\u003e\n\u003cli\u003ePowered speaker systems with RCA input\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eNot ideal for\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eUSB, optical, coaxial or Bluetooth sources without a separate DAC\u003c\/li\u003e\n\u003cli\u003eDirectly driving passive speakers\u003c\/li\u003e\n\u003cli\u003eBalanced headphone or XLR systems\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eEMiUZEK Buying Notes\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eGR70 is an analog headphone amplifier\/preamp; digital sources require a DAC with RCA output.\u003c\/li\u003e\n\u003cli\u003eIts RCA output cannot power passive speakers directly; use powered speakers or a power amplifier.\u003c\/li\u003e\n\u003cli\u003eUse only officially confirmed compatible tubes and allow installed tubes to cool before handling.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cstyle\u003e@media (min-width:650px){.pbg__notes .emiuzek-product-content-images{width:calc(148.148% + 50px)!important;margin-left:calc(-48.148% - 50px)!important}}@media(max-width:649px){.pbg__notes .emiuzek-product-content-images{width:100%!important;margin-left:0!important}}.emiuzek-product-content-images img{display:block;width:100%;height:auto}\u003c\/style\u003e\u003cdiv class=\"emiuzek-product-content-images\" style=\"margin:32px 0\"\u003e\n\u003cp style=\"margin:24px auto\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0604\/7422\/8829\/files\/Fosi_Audio_GR70_Tube_Headphone_Amp-03.webp?v=1761102474\" alt=\"Quad-Tube Dual-Stage Amplification\" loading=\"lazy\" style=\"display:block;width:100%;max-width:1100px;height:auto;margin:0 auto\"\u003e\u003c\/p\u003e\n\u003cp style=\"margin:24px auto\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0604\/7422\/8829\/files\/Fosi_Audio_GR70_Tube_Headphone_Amp-17.webp?v=1761102553\" alt=\"Product Overview\" loading=\"lazy\" style=\"display:block;width:100%;max-width:1100px;height:auto;margin:0 auto\"\u003e\u003c\/p\u003e\n\u003cp style=\"margin:24px auto\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0604\/7422\/8829\/files\/Fosi_Audio_GR70_Tube_Headphone_Amp-18.webp?v=1761102558\" alt=\"Product Connection and Usage Diagram\" loading=\"lazy\" style=\"display:block;width:100%;max-width:1100px;height:auto;margin:0 auto\"\u003e\u003c\/p\u003e\n\u003c\/div\u003e\u003ch2\u003eFrequently asked questions\u003c\/h2\u003e\u003ch3\u003eDoes GR70 include a DAC?\u003c\/h3\u003e\u003cp\u003eNo. It accepts analog RCA input.\u003c\/p\u003e\u003ch3\u003eCan it power passive speakers?\u003c\/h3\u003e\u003cp\u003eNo. A separate power amplifier is required.\u003c\/p\u003e\u003ch3\u003eWhich headphones are supported?\u003c\/h3\u003e\u003cp\u003eThe official specification covers 16–300Ω using selectable low\/high impedance modes.\u003c\/p\u003e\u003ch3\u003eDoes it have balanced output?\u003c\/h3\u003e\u003cp\u003eNo. Headphone outputs are 3.5mm and 6.35mm, with RCA pre-output.\u003c\/p\u003e\u003ch3\u003eCan it be used as a preamplifier?\u003c\/h3\u003e\u003cp\u003eYes, through the rear RCA output.\u003c\/p\u003e\u003ch3\u003eWhich tubes are supplied?\u003c\/h3\u003e\u003cp\u003eThe official package lists two 5654 tubes and two 6Ж4\/6Ж8 tubes.\u003c\/p\u003e\u003ch2\u003eHOW TO CONNECT\u003c\/h2\u003e\u003ch3\u003eAnalog headphone system\u003c\/h3\u003e\u003cp\u003eSource icon: streamer\u003cbr\u003eSource: DAC \/ streamer with RCA output\u003cbr\u003eConnection: RCA line input\u003cbr\u003eOutput connection: 3.5mm or 6.35mm output\u003cbr\u003eTarget icon: headphones\u003cbr\u003eOutput: Wired headphones\u003c\/p\u003e\u003ch3\u003ePowered speaker system\u003c\/h3\u003e\u003cp\u003eSource icon: streamer\u003cbr\u003eSource: Analog source \/ DAC\u003cbr\u003eConnection: RCA line input\u003cbr\u003eOutput connection: RCA pre-output\u003cbr\u003eTarget icon: speakers\u003cbr\u003eOutput: Powered speakers\u003c\/p\u003e\u003ch3\u003eSeparate power amplifier system\u003c\/h3\u003e\u003cp\u003eSource icon: streamer\u003cbr\u003eSource: Analog source \/ DAC\u003cbr\u003eConnection: RCA line input\u003cbr\u003eOutput connection: RCA pre-output\u003cbr\u003eTarget icon: amplifier\u003cbr\u003eOutput: Power amplifier driving passive speakers\u003c\/p\u003e\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\u003ch3\u003eAnalog connections\u003c\/h3\u003e\u003cdiv style=\"width:100%;overflow-x:auto\"\u003e\u003ctable style=\"width:100%;border-collapse:collapse;table-layout:fixed\"\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth style=\"width:42%;padding:11px;border:1px solid #ddd;text-align:left\"\u003eFeature\u003c\/th\u003e\n\u003cth style=\"padding:11px;border:1px solid #ddd;text-align:left\"\u003eSpecification\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\" style=\"width:42%;padding:11px;border:1px solid #ddd;text-align:left;vertical-align:top\"\u003eInput\u003c\/th\u003e\n\u003ctd style=\"padding:11px;border:1px solid #ddd;vertical-align:top\"\u003eRCA line input\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\" style=\"width:42%;padding:11px;border:1px solid #ddd;text-align:left;vertical-align:top\"\u003eOutputs\u003c\/th\u003e\n\u003ctd style=\"padding:11px;border:1px solid #ddd;vertical-align:top\"\u003eRCA pre-output; 3.5mm and 6.35mm headphone outputs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\" style=\"width:42%;padding:11px;border:1px solid #ddd;text-align:left;vertical-align:top\"\u003eAmplification\u003c\/th\u003e\n\u003ctd style=\"padding:11px;border:1px solid #ddd;vertical-align:top\"\u003eClass-A tube\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\" style=\"width:42%;padding:11px;border:1px solid #ddd;text-align:left;vertical-align:top\"\u003eTube complement\u003c\/th\u003e\n\u003ctd style=\"padding:11px;border:1px solid #ddd;vertical-align:top\"\u003e2 × 5654W; 2 × 6Ж4\/6Ж8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003c\/div\u003e\u003ch3\u003eHeadphone and power\u003c\/h3\u003e\u003cdiv style=\"width:100%;overflow-x:auto\"\u003e\u003ctable style=\"width:100%;border-collapse:collapse;table-layout:fixed\"\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth style=\"width:42%;padding:11px;border:1px solid #ddd;text-align:left\"\u003eFeature\u003c\/th\u003e\n\u003cth style=\"padding:11px;border:1px solid #ddd;text-align:left\"\u003eSpecification\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\" style=\"width:42%;padding:11px;border:1px solid #ddd;text-align:left;vertical-align:top\"\u003eRated output\u003c\/th\u003e\n\u003ctd style=\"padding:11px;border:1px solid #ddd;vertical-align:top\"\u003e90mW @ 32Ω\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\" style=\"width:42%;padding:11px;border:1px solid #ddd;text-align:left;vertical-align:top\"\u003eMaximum output\u003c\/th\u003e\n\u003ctd style=\"padding:11px;border:1px solid #ddd;vertical-align:top\"\u003e300mW @ 32Ω\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\" style=\"width:42%;padding:11px;border:1px solid #ddd;text-align:left;vertical-align:top\"\u003eHeadphone impedance\u003c\/th\u003e\n\u003ctd style=\"padding:11px;border:1px solid #ddd;vertical-align:top\"\u003eLow: 16–120Ω; High: 120–300Ω\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\" style=\"width:42%;padding:11px;border:1px solid #ddd;text-align:left;vertical-align:top\"\u003eRCA output level\u003c\/th\u003e\n\u003ctd style=\"padding:11px;border:1px solid #ddd;vertical-align:top\"\u003e1.2V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\" style=\"width:42%;padding:11px;border:1px solid #ddd;text-align:left;vertical-align:top\"\u003eSNR\u003c\/th\u003e\n\u003ctd style=\"padding:11px;border:1px solid #ddd;vertical-align:top\"\u003e≥97dB\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\" style=\"width:42%;padding:11px;border:1px solid #ddd;text-align:left;vertical-align:top\"\u003ePower input\u003c\/th\u003e\n\u003ctd style=\"padding:11px;border:1px solid #ddd;vertical-align:top\"\u003eDC 12V \/ 3A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003c\/div\u003e\u003ch2\u003eAdditional Product Content\u003c\/h2\u003e\u003ch3\u003eComparison: Which Fosi Audio model is right for you?\u003c\/h3\u003e\u003cdiv style=\"overflow-x:auto\"\u003e\u003ctable style=\"width:100%;border-collapse:collapse;min-width:680px\"\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eModel\u003c\/th\u003e\n\u003cth style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eGR40\u003c\/th\u003e\n\u003cth style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eGR70\u003c\/th\u003e\n\u003cth style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eK7\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eProduct position\u003c\/th\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eTube DAC \/ headphone amp \/ preamp\u003c\/td\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eAnalog tube headphone amp \/ preamp\u003c\/td\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eBalanced digital DAC \/ headphone amp\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eDigital inputs\u003c\/th\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eUSB, optical, coaxial, Bluetooth\u003c\/td\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eNone\u003c\/td\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eUSB, optical, coaxial, Bluetooth\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eHeadphone outputs\u003c\/th\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003e3.5mm\u003c\/td\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003e3.5mm and 6.35mm\u003c\/td\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003e3.5mm and 4.4mm balanced\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eSpeaker-system output\u003c\/th\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eRCA pre-out\u003c\/td\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eRCA pre-out\u003c\/td\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eRCA line output\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eBest use\u003c\/th\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eDigital sources with tube stage\u003c\/td\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eAnalog tube headphone system\u003c\/td\u003e\n\u003ctd style=\"padding:10px;border:1px solid #ddd;text-align:left\"\u003eHigh-output HiFi and gaming\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003c\/div\u003e","brand":"Fosi Audio","offers":[{"title":"Silvery \/ US","offer_id":43725789069405,"sku":"Fosi-Audio-GR70-Silvery-US","price":925.0,"currency_code":"BRL","in_stock":true},{"title":"Silvery \/ AU","offer_id":43725789233245,"sku":"Fosi-Audio-GR70-Silvery-AU","price":1192.0,"currency_code":"BRL","in_stock":true},{"title":"Silvery \/ EU","offer_id":43725789266013,"sku":"Fosi-Audio-GR70-Silvery-EU","price":1192.0,"currency_code":"BRL","in_stock":true},{"title":"Silvery \/ UK","offer_id":43725789298781,"sku":"Fosi-Audio-GR70-Silvery-UK","price":1192.0,"currency_code":"BRL","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0604\/7422\/8829\/files\/Fosi_Audio_GR70.webp?v=1785223557","url":"https:\/\/emiuzek.com\/pt-br\/products\/fosi-audio-gr70-tube-headphone-amp","provider":"EMiUZEK","version":"1.0","type":"link"}