Cayin RU9 NuTube DAC/Amp Review

Cayin's RU9 puts a Korg NuTube 6P1 stage and two AK4493SEQ DAC chips into a portable DAC and amp, with three timbre options: Classic Tube, Modern Tube and Solid State. The page lists 32-bit/768kHz PCM, native DSD512, Bluetooth V5.1 and 3.5mm and 4.4mm outputs, at a weight of 150g. HiFiGO's page prices it at $499.99.

Specifications

Options and pricing

Only one option appears, RU9, at $499.99 under the Color heading, orderable when the page was read and with no crossed-out price. The page says a magnetic leather case comes with it, and its feature list also names an L-shaped USB connector cable. Outputs are one 3.5mm single-ended and one 4.4mm balanced port, and Hyper mode needs the mode selector on DC and a power adapter connected, which the page text does not say is included.

How it compares

The iBasso PB6 MACAW is $499 and its title names four JAN6418 tubes in a headphone amplifier, where the RU9 has two AK4493SEQ chips. The QULOOS MUB1 is $449.99 and its line lists 32-Bit/384kHz PCM and Native DSD256, against 32-bit/768kHz and DSD512 on the RU9 page. The MUSE HiFi M6 Double at $390 carries JAN 6418 and IN-17 in its title. The RU9 suits buyers who want a NuTube stage and a DAC in one unit with higher listed sample rates; the PB6 suits those who already have a DAC and want four tubes.

Shipping, returns and warranty

HiFiGO sells from hifigo.com and says every order leaves its warehouse in China, usually 1-3 business days after it is placed, and says its delivery times are estimates, not promises. Its shipping policy gives the United States 1-2 weeks (about 10 days on average) by Priority and 6-10 days by Premium, both with duties and taxes prepaid by the store; Canada 2-3 weeks; the United Kingdom 1-2 weeks; and Australia 10-15 days. Express couriers (DHL, UPS, FedEx) take 3-7 days, but then the buyer pays any duties and taxes. No shipping page names New Zealand, PO boxes are not accepted, and the free-shipping thresholds differ between the store's own pages, so check the cart. One of its two shipping pages adds that a lost parcel on an order above $50 gets only a 50% refund. A US buyer reported a $40 tariff charge in August 2025, after which HiFiGO said it had added a customs notice at checkout.

Read the return terms before you order. The homepage advertises 7-day returns. Both of HiFiGO's policy pages offer a 7-day dead-on-arrival cover (a replacement or a full refund, with the return postage refunded) and also describe 30-day returns, but a request made 7 to 30 days after delivery loses 30% of the MSRP as a restocking fee (10% more if the packaging is incomplete), plus shipping both ways and duties, and the FAQ on the same pages says there is no refund or exchange once 7 days have passed. One version recommends reselling an opened product locally. Custom IEMs and custom cables cannot be returned, no return address is published, and buyers describe sending items back to China.

HiFiGO's warranty runs one year from the order date for parts and labor; its policy names desktop DACs and amps, IEMs and dongles at one year and gives cables and adapters three months. HiFiGO decides between repair and replacement, the buyer pays the shipping, and faulty items go back for service, not for a refund. Claims go to [email protected], the only contact the store lists: its pages name no company, street address or phone, and its terms are governed by the laws of China.

On Trustpilot, HiFiGO had 4.6 out of 5 from 378 reviews when we checked on 2026-10-28 (91% five-star, 5% one-star), and it had replied to about 75% of negative reviews; Trustpilot notes the store has not invited customers to review recently. The one-star reviews mostly concern the short return window and the deductions on returns, items listed in stock that turned out back-ordered, slow email support and a tariff charge on a US delivery in 2025. HiFiGO says its products are genuine and come in the brands' retail packaging; it does not claim to be an authorized dealer.