{"type":"firestarter.listing","listing":{"id":"lst_HkI-gW7u","product_name":"YULONG DAART A39 Desktop R2R Pre-Amp & Headphone Amplifier","category":"Headphone Amp","description":"\nA compact powerhouse with serious control\n\nThe Yulong A39 is a Class-A headphone amplifier and reference-grade preamp that blends sophisticated tech with warm, dynamic sound. Designed to handle everything from high-impedance over-ears to sensitive IEMs, it delivers 6W of Class-A balanced power and 99-step R2R volume control in a compact, CNC-machined aluminum chassis. Paired with its retro VU meters and IPS display, it brings the brains, the brawn, and a little bit of nostalgia to your desk.\nClass-A power—without the heatstroke\nAt the heart of the A39 is a 6W constant-current Class-A amplifier, built from discrete components and driven by 16 medium-power transistors. This means rich harmonics, low distortion (0.0002%), and serious drive—without needing a fan or a fire extinguisher. The all-aluminum case pulls double duty as a heatsink, keeping things cool even when the evening gets away from you.\nReal-time monitoring and protection\nUnder the hood, a CPU running a custom Linux system manages thermal conditions, overcurrent protection, voltage, and startup sequences. So even if you’re swapping headphones mid-session or pushing power-hungry cans, the A39 keeps everything running safely and quietly.\nVolume that doesn’t suck (your tone away)\nTraditional volume pots introduce noise and lose detail. The A39 uses a CPU-controlled relay system paired with an R2R resistor ladder, giving you 99 steps of transparent, lossless attenuation. The relay locks in a closed loop, eliminating electromagnetic interference, while the R2R network keeps the signal pure.\nBuilt to pair with the D39 DAC\nThe A39 is designed to visually and functionally pair with Yulong’s D39 streaming DAC. Together, they form a full desktop control center—small enough to fit on an A4 sheet, powerful enough to anchor your entire system.\nLooks smart, acts smarter\nThe IPS LCD screen shows dynamic spectrums and classic VU meters—one eye on nostalgia, the other on precision. The intuitive knob or included remote ma","images":["https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-xduoo-dac-digital-to-analog-converter-yulong-daart-a39-desktop-r2r-pre-amp-headphone-amplifier-1154368343.jpg?v=1743798656","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-xduoo-dac-digital-to-analog-converter-yulong-daart-a39-desktop-r2r-pre-amp-headphone-amplifier-1154368347.jpg?v=1743798762","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-xduoo-dac-digital-to-analog-converter-yulong-daart-a39-desktop-r2r-pre-amp-headphone-amplifier-1154368344.jpg?v=1743798660","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-xduoo-dac-digital-to-analog-converter-yulong-daart-a39-desktop-r2r-pre-amp-headphone-amplifier-1154368345.jpg?v=1743798662","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-xduoo-dac-digital-to-analog-converter-yulong-daart-a39-desktop-r2r-pre-amp-headphone-amplifier-1154368342.jpg?v=1743798652","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-xduoo-dac-digital-to-analog-converter-yulong-daart-a39-desktop-r2r-pre-amp-headphone-amplifier-1154368346.jpg?v=1743798760"],"price":1099,"currency":"USD","in_stock":true,"inventory_qty":19998,"dynamic_pricing":false,"listed_at":"2026-06-20T16:25:57.684Z"},"share_url":"https://firestarter.network/l/lst_HkI-gW7u","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_HkI-gW7u' — this pins the purchase to this exact listing, skipping product search — plus request: 'Buy YULONG DAART A39 Desktop R2R Pre-Amp & Headphone Amplifier' and a budget_max comfortably above $1099.00 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."]}}