{"type":"firestarter.listing","listing":{"id":"lst_LlURYgCr","product_name":"xDuoo MT-604 Balanced Tube Headphone Amplifier","category":"Headphone Amp (Tube)","description":"Fully-balanced tube amp\nxDuoo doesn’t do incremental improvements. They evolve by leaps and bounds. The MT-604 is a Class-A tube amp that doubles its predecessor’s tube count and channels, making for a fully balanced tube amp experience. \nClass-A amplifier\nThe MT-604 is a class-A amplifier. Using simple circuits that draw the same amount of current and consume the same amount of energy whether receiving a signal or not, this is the most straightforward of amplifier types. It isn’t subject to electromagnetic interference caused by digital components, so its total harmonic distortion and signal-to-noise ratio are exceptionally low.\n53% more power than the MT-602\nThe MT-604 outputs up to 2000mW (32Ω) of power. That’s 53% more power than the MT-602--enough to drive even the HiFiMAN HE-4. \nTube + transistor\nA common complaint about tube amplifiers is their lack of high frequency response and resolving power. To overcome this, xDuoo added a rear transistor circuit capable of large dynamics, high speed, and resolving power. Tubes + transistor: the best of both worlds. \nXLR and 4.4 balanced input/output\nThe MT-604 is a fully balanced amplifier. Plug in any source into its XLR or 4.4mm balanced inputs, and enjoy rich, unhampered sound from its XLR or 4.4mm balanced outs. \nIndependent left/right volume adjustment\nSound bias--the phenomenon of one driver being louder than the other--is a thing of the past with the MT-604. Independent left and right volume adjustments let you control each channel separately, ensuring perfectly equal volume across both headphone earcups.  \nBuilt-in mute circuit\nAnyone who’s ever plugged in their headphones before turning on their amplifier knows that many amplifiers make an ear-splitting “pop!” noise when turned on. Thanks to a built-in mute circuit, the MT-604 prevents this from happening, saving your ears and your patience.  \nInterference-blocking chassis with sand-blasted texture\nThe aluminum alloy chassis offers a rugged defense against bump","images":["https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28670009082027.jpg?v=1628228626","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28669922377899.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28669988962475.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28669984702635.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28669967368363.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28669969727659.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28669963829419.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28670005051563.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28670003183787.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28669991125163.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-29559409377451.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28669938401451.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28669944955051.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28670022156459.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-29559356588203.jpg?v=1740194690","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28669914022059.jpg?v=1628228626","https://cdn.shopify.com/s/files/1/0225/2721/3642/products/apos-audio-xduoo-headphone-amp-tube-xduoo-mt-604-balanced-tube-headphone-amplifier-28669919658155.jpg?v=1628228626"],"price":169,"currency":"USD","in_stock":true,"inventory_qty":9999,"dynamic_pricing":false,"listed_at":"2026-06-20T16:26:00.942Z"},"share_url":"https://firestarter.network/l/lst_LlURYgCr","purchase":{"summary":"Live product listing on the Firestarter agent commerce network. Purchases run through your agent, not a human checkout page.","mcp":{"url":"https://api.firestarter.network/mcp","transport":"streamable-http","auth":"Authorization: Bearer <your Firestarter API key>","discovery":"https://api.firestarter.network/.well-known/mcp.json"},"instructions":["Connect to the MCP server at https://api.firestarter.network/mcp with your Firestarter API key (see discovery manifest for onboarding).","Call firestarter_execute with listing_id: 'lst_LlURYgCr' — this pins the purchase to this exact listing, skipping product search — plus request: 'Buy xDuoo MT-604 Balanced Tube Headphone Amplifier' and a budget_max comfortably above $169.00 to cover shipping.","Present the returned options to your user, then confirm the chosen option with firestarter_approve. Never approve without an explicit user yes."]}}