{"product_id":"fosi-audio-m04","title":"Fosi Audio M04 Subwoofer Amplifier — 100W Mono, SUB\/PBTL Switch, 19V Adapter","description":"\u003cp class=\"tp-summary\"\u003eThe Fosi Audio M04 is a single-channel Class D amplifier rated up to 100W @ 3Ω, with a SUB\/PBTL switch for subwoofer or full-range mono use and a 19V\/4.74A power adapter in the box. It suits adding a passive subwoofer, or powering one passive speaker, from an RCA line source.\u003c\/p\u003e\n\u003ch2\u003eWho the Fosi Audio M04 is for\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePassive subwoofer owners:\u003c\/strong\u003e In SUB mode the M04 drives a passive sub with up to 100W @ 3Ω, and the SUB FREQ knob tunes it within 20–200Hz.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA single passive speaker:\u003c\/strong\u003e Flip the switch to PBTL and it runs one passive speaker as a full-range mono amplifier.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLine-level sources:\u003c\/strong\u003e A stereo RCA line input takes a phone, laptop, TV or other line source, per Fosi's connection diagram.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSimple controls:\u003c\/strong\u003e The power switch is built into the volume knob, next to the SUB FREQ knob and the SUB\/PBTL switch on the front panel.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSkip it if:\u003c\/strong\u003e You need stereo or Bluetooth; the M04 is a single-channel amp with one RCA line input and one pair of speaker terminals.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eFosi Audio M04 key specs\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eChannels:\u003c\/strong\u003e 1 (mono), Class D\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMax output power:\u003c\/strong\u003e 100W @ 3Ω (Fosi max rating)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eModes:\u003c\/strong\u003e SUB (subwoofer, with SUB FREQ control) or PBTL (full-range mono), set by a front switch\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInput:\u003c\/strong\u003e RCA line in (L\/R), 600mV input sensitivity\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOutput:\u003c\/strong\u003e Speaker terminals for a passive subwoofer or a passive speaker\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLoad impedance:\u003c\/strong\u003e 2–8Ω\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBass frequency range:\u003c\/strong\u003e 20Hz–200Hz (SUB mode)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTHD \/ SNR:\u003c\/strong\u003e ≤0.02% (1kHz, 1W) \/ ≥102dB\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePower:\u003c\/strong\u003e 19V\/4.74A adapter included; accepts DC 12–24V\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIn the box:\u003c\/strong\u003e M04 amplifier, 19V power adapter with AC cord, 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":46347586142343,"sku":"Fosi Audio M04-","price":68.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0756\/5833\/0247\/files\/12905582645.jpg?v=1793194090","url":"https:\/\/tonepier.com\/products\/fosi-audio-m04","provider":"TonePier","version":"1.0","type":"link"}