{"product_id":"fosi-audio-gr70","title":"Fosi Audio GR70 | Tube Headphone Amplifier and Preamp","description":"\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0023\/9255\/5595\/files\/fosi-audio-logo.webp?v=1753282757\" alt=\"fosi-audio-logo\" style=\"display: block; margin-left: auto; margin-right: auto; width: 65%;\"\u003e\u003c\/p\u003e\n\u003ch4\u003eThe Fosi Audio GR70 Features a Thoughtfully Selected Vacuum Tube Combination For a Highly Musical and Authentic Analog Sound\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eDesktop vacuum tube headphone amp and preamp\u003c\/li\u003e\n\u003cli\u003eGeneral Electric 5654W and Sovtek 6Ж4 replaceable tubes\u003c\/li\u003e\n\u003cli\u003eFeatures adjustable impedance, bass and treble control\u003c\/li\u003e\n\u003cli\u003eSupports 16-\u003cmeta charset=\"UTF-8\"\u003e \u003cspan\u003e300Ω headphone impedance\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cimg alt=\"Fosi Audio GR70 tube headphone amp sitting front right 3 quarter angle on wooden desk with bookshelf speaker behind, over ear headphones, iphone and keyboard next to it\" height=\"1360\" width=\"2048\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0023\/9255\/5595\/files\/fosi-audio-gr70-banner.webp?v=1753714915\"\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eQuad-Tube Dual Amplification\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003eBuilt with two replaceable General Electric 5654W and two Sovtek 6Ж4 vacuum tubes, the Fosi GR70 amp offers a customizable auditory experience. Immerse yourself in the authentic warmth and smoothness of analog audio. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cmeta charset=\"UTF-8\"\u003eThe 5654W tubes boost voltage, while the 6Ж4 tubes handle power amplification. This setup delivers balanced, transparent, and textured sound.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eVintage Charm with Modern Precision\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003eThe GR70 is a two-in-one headphone amp and preamp. Easily integrate this tube preamp into your home audio system with its multiple headphone jacks and RCA input\/output options. This tube headphone amp preamplifier offers intuitive controls, including a large volume knob, dual-side ventilation holes, bass\/treble controls, and high + low impedance mode switching.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eAdditional Features\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eSwitchable Output Impedance\u003c\/strong\u003e\u003cbr\u003eEnsures optimal control and cleaner sound across a wide range of full-size headphones and IEMs.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eEfficient Cooling and Thermal Stability\u003c\/strong\u003e\u003cbr\u003eKeeps dust out while maintaining airflow to protect internal components.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eCompact, Yet Powerful\u003c\/strong\u003e\u003cbr\u003eCrafted with a CNC-machined aluminum alloy body, the GR70 is both durable and refined. Despite its compact size, it delivers up to 300mW power output and 1.2V RCA output with SNR ≥97dB—offering warm, clean, and dynamic sound.\u003cbr\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cstrong\u003eTwo-in-One\u003c\/strong\u003e\u003cbr\u003e\u003cmeta charset=\"UTF-8\"\u003eIt supports low and high impedance modes switching to adapt 16Ω-300Ω headphones, and features 6.35mm\/3.5mm headphone jacks on the front and RCA Input\/Output on the rear for home audio HiFi system integration.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cimg alt=\"Fosi Audio GR70 tube amp connections diagram\" height=\"1500\" width=\"2048\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0023\/9255\/5595\/files\/fosi-audio-gr70-connections.webp?v=1753714778\"\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan\u003eSpecifications\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eInput:\u003c\/strong\u003e RCA\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eOutput:\u003c\/strong\u003e RCA, 6.35mm headphones, 3.5mm headphones\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRated Power Output\u003c\/strong\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eLow Gain: 67mW\/32Ω\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eHigh Gain: 830mW\/32Ω\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeadphone Impedance\u003c\/strong\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eLow Impedance Mode: 16Ω-120Ω\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003eHigh Impedance Mode: 120Ω-300Ω\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eFrequency Response:\u003c\/strong\u003e 20Hz-20kHz (±1dB)\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eSNR:\u003c\/strong\u003e ≥93dB\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eDynamic Range:\u003c\/strong\u003e 94dB\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTHD\u003c\/strong\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eRCA OUT: ≤0.26%\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePHONE: ≤0.5%\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNoise Floor\u003c\/strong\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eRCA OUT: ≤20uV\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePHONE: 56uV\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCross Talk\u003c\/strong\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eRCA OUT: -63dB\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003ePHONE: -65dB\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003ePower Input:\u003c\/strong\u003e DC 12V\/3A\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cspan\u003eIn the Box\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003eFosi Audio GR70 Tube Amp\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e(2x) 6Ж4 Vacuum Tube\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e(2x) 5654W Vacuum Tube\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e12V\/3A power supply\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e(2x) Tube cover\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0023\/9255\/5595\/files\/GR70_User_Manual.pdf?v=1753714299\" title=\"Fosi Audio GR70 Amp user manual\" rel=\"noopener\" target=\"_blank\"\u003e\u003cspan\u003eUser manual\u003c\/span\u003e\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Fosi Audio","offers":[{"title":"Default Title","offer_id":41640162263115,"sku":"FSI-GR70","price":199.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0023\/9255\/5595\/files\/fosi-audio-gr70-thumb.webp?v=1753714620","url":"https:\/\/bloomaudio.mom\/products\/fosi-audio-gr70","provider":"Bloom Audio","version":"1.0","type":"link"}