SMSL PA400 GaN Power Amplifier Review

The PA400 is SMSL's Class D power amplifier built on Infineon gallium nitride (GaN) transistors, listed at $555. The page rates it at about 250W per channel into 4Ω in stereo mode and 500W into 8Ω in mono block mode, with THD+N of 0.003% and a 115dB SNR, and it gives XLR and RCA inputs, a size of 254x47.7x242mm and a weight of about 2.58Kg.

Specifications

Options and pricing

Four options are listed, all Silver and all $555: PA400 Silver-EU Plug, PA400 Silver-AU Plug, PA400 Silver-UK Plug and PA400 Silver-US Plug. All four showed as orderable. The names differ only by the plug they name, and the page describes no other difference between them. The page text lists no cables or accessories.

How it compares

The TOPPING B200 Mono Pure Power Amplifier at $599 carries 'Mono' in its name, while the PA400 at $555 works in stereo or mono block modes per its own page. The TOPPING LA90 Discrete Ultra-high Performance Power Amplifier at $799 has a spec line naming a discrete NFCA circuit, while the PA400's page names GaN transistors. The SMSL AO200 Digital Amplifier Bluetooth 5.0 Balanced Input at $279 has Bluetooth 5.0 in its name; the PA400 lists XLR and RCA inputs only.

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.