{"product_id":"fosi-audio-gr70","title":"Fosi Audio GR70 Tube Headphone Amp \u0026 Preamp — Class A, 4 Tubes, Bass\/Treble","description":"\u003cp class=\"tp-summary\"\u003eThe Fosi Audio GR70 is a Class A, output-transformerless tube headphone amp and preamp with two 5654W voltage tubes and two 6Zh4\/6Zh8 power tubes, rated 90mW (300mW max) into 32Ω, plus 6.35mm and 3.5mm headphone jacks and an RCA preamp output. It suits listeners who want tube amplification for 16–300Ω headphones, or a tube stage between a DAC and powered speakers or a power amp.\u003c\/p\u003e\n\u003ch2\u003eWho the Fosi Audio GR70 is for\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeadphone listening:\u003c\/strong\u003e A Hi-Z\/Lo-Z switch matches 16–120Ω or 120–300Ω headphones, and the front panel has both 6.35mm and 3.5mm jacks.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTube preamp duty:\u003c\/strong\u003e RCA in and a 1.2V RCA out let it sit between a DAC or CD player and powered speakers or a power amplifier.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTube rolling:\u003c\/strong\u003e All four tubes are replaceable, and 6AC7 or CV849 tubes can substitute for the 6Zh4\/6Zh8 power tubes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTone shaping:\u003c\/strong\u003e Bass and treble knobs with center detents work whether you use the headphone jacks or the preamp output.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSkip it if:\u003c\/strong\u003e You need a DAC or Bluetooth; the GR70 is analog-only with a single RCA input, so digital sources need a separate DAC.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eFosi Audio GR70 key specs\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAmplifier type:\u003c\/strong\u003e Class A, output-transformerless (OTL) tube headphone amp and preamp\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTubes:\u003c\/strong\u003e 2 × 5654W (voltage stage), 2 × 6Zh4\/6Zh8 (power stage)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeadphone power:\u003c\/strong\u003e 90mW @ 32Ω rated, 300mW @ 32Ω max\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeadphone impedance:\u003c\/strong\u003e Lo-Z 16–120Ω, Hi-Z 120–300Ω\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConnections:\u003c\/strong\u003e RCA in; RCA out (1.2V); 6.35mm and 3.5mm headphone jacks\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTone controls:\u003c\/strong\u003e Bass and treble with center detents\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSNR \/ frequency response:\u003c\/strong\u003e ≥97dB \/ 20Hz–20kHz (±1dB)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePower:\u003c\/strong\u003e DC 12V\/3A adapter, included\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSize:\u003c\/strong\u003e 187 × 129 × 42 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIn the box:\u003c\/strong\u003e GR70, 2 × 5654 tubes, 2 × 6Zh4\/6Zh8 tubes, 2 tube protection covers, 12V\/3A power supply, user manual\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"tp-trust\"\u003eGenuine Fosi Audio stock. Free shipping on every order, 45-day returns.\u003c\/p\u003e","brand":"Fosi Audio","offers":[{"title":"Default Title","offer_id":46279093452935,"sku":"Fosi Audio GR70 -orang-","price":200.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0756\/5833\/0247\/files\/7982938295.jpg?v=1792672802","url":"https:\/\/tonepier.com\/products\/fosi-audio-gr70","provider":"TonePier","version":"1.0","type":"link"}