{"type":"firestarter.listing","listing":{"id":"lst_l2AdY4Zg","product_name":"Cayin RU3 Portable USB DAC/Amp","category":"DAC (Digital-to-Analog Converter)","description":"Note: We currently only have black in stock.\n32-Bit / 768 kHz USB DAC Dongle\nThe Cayin RU3 is a portable USB DAC and headphone amplifier dongle that combines an ESS ES9069Q DAC, SPV5068 RISC-V dual-core audio processor, 32-bit / 768 kHz PCM support, native DSD512 playback, 3.5mm single-ended and 4.4mm balanced outputs, HYP / STD power modes, app control, and a 0.96-inch IPS color display in a compact CNC aluminum chassis.\nHigh-resolution decoding\nThe RU3 uses a single ESS ES9069Q DAC with a dual-channel design based on ESS HyperStream IV Dual DAC architecture and SABRE HiFi technology. It supports PCM up to 32-bit / 768 kHz and native DSD512, giving you broad high-resolution file support whether you're listening from a phone, laptop, or tablet. \nFully-balanced power\nThe RU3 pairs two TI OPA1602 op-amps with two SGM8262 low-noise headphone amplifier chips to create a fully-balanced quad-drive architecture. That means the left and right channels are separated, which helps preserve imaging, channel balance, and clean output. In Hyper Mode, the 4.4mm balanced output delivers up to 560mW + 560mW at 32Ω, while the 3.5mm single-ended output delivers up to 180mW + 180mW at 32Ω.\nTwo power modes\nThe RU3 gives you two ways to manage output. HYP Mode unlocks the RU3’s higher power output for headphones that need more drive, while STD Mode lowers power draw and heat for everyday listening from mobile devices. \nPhone and line outputs\nThe RU3 includes both 3.5mm single-ended and 4.4mm balanced outputs, and both can operate as phone output or line output. Use phone output when connecting headphones or IEMs directly. Use line output when sending signal to an external amplifier.\nApp-based control\nThrough the Cayin Control App, the RU3 gives you access to volume, output mode, channel balance, gain, digital filters, UAC mode, UI themes, and EQ. The app includes 100-step volume control, two power modes, two gain levels, five digital filters, four UI themes, 20-step channel balance, and ","images":["https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254666.jpg?v=1778272569","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254665.jpg?v=1778272512","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254664.jpg?v=1778272450","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254663.jpg?v=1778272388","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254662.jpg?v=1778272329","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254661.jpg?v=1778272269","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254660.jpg?v=1778272210","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254659.jpg?v=1778272149","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254658.jpg?v=1778272090","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254657.jpg?v=1778272031","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254656.jpg?v=1778271969","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254655.jpg?v=1778271909","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254654.jpg?v=1778271849","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254653.jpg?v=1778271791","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254652.jpg?v=1778271729","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254651.jpg?v=1778271668","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254650.jpg?v=1778271609","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254649.jpg?v=1778271551","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237254648.jpg?v=1778271492","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237269122.jpg?v=1778286010","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237269121.jpg?v=1778285949","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-cayin-dac-digital-to-analog-converter-cayin-ru3-portable-usb-dac-amp-1237269120.jpg?v=1778285889"],"price":99,"currency":"USD","in_stock":true,"inventory_qty":9999,"dynamic_pricing":false,"listed_at":"2026-06-20T16:25:55.806Z"},"share_url":"https://firestarter.network/l/lst_l2AdY4Zg","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_l2AdY4Zg' — this pins the purchase to this exact listing, skipping product search — plus request: 'Buy Cayin RU3 Portable USB DAC/Amp' and a budget_max comfortably above $99.00 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."]}}