The xDuoo MT-603 is a compact tube buffer and source switcher that routes four analog inputs, three RCA pairs and a front 3.5mm jack, through a 12AU7 tube to one RCA output at 0dB gain. It suits listeners whose amplifier or powered speakers are short on inputs and who want a tube stage in the chain.
Who the xDuoo MT-603 is for
Amps short on inputs: Four front push buttons select AUX1 to AUX4, so up to four sources share a single input on your amplifier or powered speakers.
Adding a tube stage: The selected source runs through a 12AU7 tube buffer at 0dB gain, so the tube joins the chain without raising the signal level.
Phones and portable players: AUX4 is a front-panel 3.5mm jack for a phone, laptop or portable player, next to three RCA inputs on the back.
Compact racks and desks: The aluminum chassis measures 12 × 7.8 × 4cm, uses gold-plated RCA jacks and runs from a 12V/2A DC supply.
Skip it if: you need volume control, a headphone jack or a DAC; the MT-603 has none of these, so volume stays on your amplifier and digital sources need their own DAC.
Build: Aluminum alloy chassis with sandblasted panel; gold-plated RCA jacks
Size and weight: 12 × 7.8 × 4cm; 0.36kg
Genuine xDuoo stock. Free shipping on every order, 45-day returns.
xDuoo MT-603 vs similar options
vs Douk Audio P1: Adds USB and Bluetooth 5.0 inputs and a 3.5mm headphone output around two tubes; pick the MT-603 to switch four wired sources (three RCA, one 3.5mm) into one RCA output through a 12AU7.
vs Douk Audio P6 MINI: Adds Bluetooth 5.0 and USB-drive inputs with two 6A2 tubes; pick the MT-603 to switch four wired analog sources, three RCA and one front 3.5mm, through a 12AU7 tube at 0dB gain.
Yes. Every unit we sell is genuine and brand-new, shipped in its original packaging, and backed by our 1-year TonePier warranty and 45-day returns.
Where does my order ship from, and how long does it take?
Every order ships from our warehouse in China, with full tracking, and most orders ship within 3 business days. Shipping is free on every order; most US orders arrive within 7–15 business days and most orders to other countries within 7–20 business days — see our shipping policy for details.
What if it isn't for me?
You get 45 days to decide. Keep the packaging, keep it in like-new condition, and send it back for a refund. Ear tips unsealed for hygiene reasons are fine — we expect you to actually listen.
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