xDuoo MU-603 Bluetooth DAC and Tube Amp Review

The MU-603 is xDuoo's DAC with a Bluetooth input and a 12AU7 tube stage, and the page lists a Qualcomm QCC3034 chip, Bluetooth 5.1, aptX HD and an ES9018K2M DAC chip. An AUX signal output lets it feed an amplifier and speaker through an audio cable, and the case is described as aluminum-shielded with an external Bluetooth antenna. The listing text gives no power figures. It costs $101.15 and the store lists two options.

Options and pricing

The store lists two orderable options, EU and UK, both at $101.15, while a specification row on the page also names US, so the option names differ between the two places. The page shows $119.00 crossed out beside the price, which is the store's own comparison and not something we checked. The listing text does not say what separates the options.

How it compares

The SMSL AO10 is $89.99 and its listing text mentions Bluetooth 5.3, against the MU-603's Bluetooth 5.1 at $101.15. The SIMGOT DEW4 Ultra is $99 and its listing text mentions CS43198 and SGM8262, while the SMSL DAC MINI is $117.03 with ES9039Q2M mentioned.

Shipping

• Methods and costs. The store's shipping page offers Standard Shipping (4PX, Yanwen or Yun Express), free for most countries, and Express Shipping (DHL Express, FedEx or SF Express) at 15-50 USD depending on the country, free for orders over 270 USD in most countries (checked 2026-11-11).
• Large items. The page says headphones and desktop DAC/AMPs count as large items, for which Express is free only for orders over $499.99.
• Delivery times. It says an in-stock order ships within 3 working days, Standard takes about 2 weeks after shipping out (up to 1-3 months for some countries, and the store makes no refund for that transit time) and Express takes about 3-7 days. Festive seasons and other circumstances can change the timing.
• Taxes and fees. The buyer pays any customs, import or processing fees. The page says Standard via YunExpress is tax-inclusive for some countries, that remote areas can carry extra Express charges, and that a parcel refused or left uncollected over taxes is deducted two-way freight and may be destroyed with no refund.
• Where it ships. The page says the store can generally ship to most countries by Express and many by Standard, and to confirm Standard with the team for your country. It cannot ship to PO boxes or APO/FPO addresses and can only use Express to Hawaii. It does not name the US, Canada, the UK, Australia or New Zealand, so confirm before you pay.
• Lost parcels. If a parcel has been in transit for at least 3 months, the page offers a one-time reshipment or a full refund for orders under $50 and a 50% refund for orders above $50.

Returns and warranty

• Returns. The return page allows returning any non-customized product that is still factory sealed within 30 days of receiving it, with the buyer paying the shipping. Email [email protected] within that period; the store asks for the return to be shipped within 5 working days of the RMA instructions and in most cases processes a refund within 5 business days of inspecting it (checked 2026-11-11).
• Opened items. A product opened within the first 7 days after delivery can be returned for the price minus a restocking fee of 35% of its retail value, including when it still works properly.
• Refund or credit. The buyer can choose a refund to the original payment method (PayPal or card) or store credit; with no answer within 48 hours of confirmation the default is store credit, which can also be prioritized during promotions, final-sale events and for items 40% or more off retail.
• Not returnable. Customized products, including faceplate designs, are non-refundable, and the page says the same applies to carry cases, cables, ear tips and other accessories, "due to hygiene purposes". If one item in a package is defective, incorrect or missing, the refund or replacement covers only that item.

• Warranty. The page gives a 1-year warranty on products, excluding carry cases, ear tips and other accessories, and 3 months on cables and adapters, from the date of purchase. It covers factory defects that affect proper function, not damage from human error, negligence, accidents, dismantling, water, abuse or modification (checked 2026-11-11).
• Not covered or limited. It does not apply to items bought elsewhere (AliExpress, Amazon, local dealers and the like), prize or giveaway items, normal wear or colour change, commercial use, or items that were stolen or went missing. Coverage is limited for products 40% or more off retail, for review units and for items repaired or modified by anyone Linsoul has not authorized.
• Claims. Email [email protected] with the order number, the issue and photos and videos of the fault. The store may ask for the unit back for a replacement. It covers shipping for some defects reported within 7 days of delivery if the fault can be shown on video or photo; after 7 days the buyer ships it back. For wrong or missing items an unboxing video of the whole sealed parcel is required.

Before you buy

Linsoul says it was founded in 2016 by the Crazy HiFi team to bring Chinese HiFi makers closer to listeners worldwide, and that it now sells other makers' products alongside four brands of its own, THIEAUDIO, Kiwi Ears, ZiiGaat and Tripowin (checked 2026-11-11).

We have not read any independent review of this product or of the store. Ratings and owner reviews shown on the store's own pages are the store's and were not verified.