Douk Audio G4 100W Mono Digital Amplifier Review

The Douk Audio G4 is a mono digital amplifier priced at $44.99, built for two jobs: driving a subwoofer, or acting as a full-frequency channel amplifier for a single speaker. It is a class-D design in a small aluminium chassis, and the listing is upfront that it is a mono amplifier, so stereo output requires two (or three) units.

A B/M switch selects the operating mode, moving between full-frequency use (20Hz-20kHz) and subwoofer use (20-200Hz), and the speaker matching follows suit: 3-10 inch full-range or crossover speakers rated 10-200W, or 4-12 inch subwoofers rated 40-200W, all at 4-8Ω impedance. Rated power is 100W with a peak of 300W, and THD is quoted at 0.001% with SNR at 103dB. Two NE5532 op amps and a Texas Instruments TPA3116 chip handle the signal, and the maker says there is no audible noise even at high output.

The inputs are a 3.5mm AUX socket and an RCA connection, covering devices with different output types. When fed a stereo signal, the G4 combines the left and right channels, analyses and processes the signal and frequency response, and then amplifies it, which the listing says results in purer low-frequency filtering and more efficient power consumption. Two units can drive left and right channels separately to keep them isolated from each other, making the G4 equally useful as a stereo pair or as a bass amp added to an existing 2.0 system. It runs on DC 12-24V through a 5.5/2.5mm jack, measures 105 x 85 x 30mm, weighs 240g, and the 19V power supply is an option at checkout.

Specifications

How it compares

At $44.99 (the option without a power adapter) the G4 is a mono amp with a B/M switch between subwoofer mode (20-200Hz) and full-frequency mode (20Hz-20kHz), rated 100W with a 300W peak and listed at THD 0.001% and SNR 103dB. The Nobsound G2 Mini costs $36.99, which is $8.00 less (also without an adapter), and is its near twin on paper: the same TPA3116 chip and NE5532 op-amp and a mode switch, with 100W listed at 2Ω in its Parameters. It adds a four-step gain switch (20/26/32/36dB), a 40-300Hz cutoff knob and a stated 0.03% THD at 1W with SNR of at least 106dB, and matches 2-8Ω speakers against the G4's 4-8Ω. The Nobsound G2 PRO costs $64.99, which is $20.00 more, for 300W max on a TPA3255D2 with a 40-300Hz cutoff, also without an adapter at that price.

Who it suits: the G4 fits a 2.1 build, or a pair of mono amps for stereo, where one mode switch and a 3-10 inch or 4-12 inch speaker match are enough; its page says it is mono and that a stereo setup needs two. The G4 page lists no gain switch or adjustable cutoff, so the G2 Mini or G2 PRO suit a subwoofer that needs tuning. The 19V adapter is a separate option: with it the G4 costs $54.99, which is $10.00 more.

Shipping, returns and warranty

• Shipping: Douk Audio's current shipping page says orders are generally processed no later than the next business day and arrive in 2-8 business days, with duties, taxes and customs fees included in the checkout price unless noted otherwise.
• Older shipping terms are still online: airmail at 10-25 days for parcels under 2 kg, DHL, UPS or FedEx at 5-8 days above that, and a line saying the store is not responsible for import duties. Check the delivery estimate and any duties at checkout.
• Returns: ask within 30 days of delivery and wait for approval before sending anything; an approved return has to ship within 7 days. Items need all packaging and accessories and no excessive wear, or the store can refuse them or refund part of the price. Refunds go to the original payment method after inspection.
• Not refunded: original and expedited shipping, duties, taxes and customs charges, unless the law requires it or the store made the error. The return page does not say who pays return postage, and the older refund page excludes mistaken orders and change-of-mind returns from free after-sale service.
• Warranty: 24 months from purchase for manufacturing defects, with free repair, a replacement unit and free shipping both ways for covered repairs. Drops, liquid, DIY repairs, lightning, extreme temperatures and misuse are excluded (partial fees may apply), and damage from weak packing on the way back may not be covered. The older refund page still says 1 year.
• Seller: the site is run by Shenzhen Anba Technology Co., Ltd (Shenzhen, China) and HONGKONG LONGSHENG Import and Export Trading Co., Limited (Hong Kong); support is by email at [email protected]. These terms cover orders placed on doukaudio.com; other sellers apply their own.

For this product, the page lists shipping to US, UK, EU, AU and Other (the Other option is priced $10.00 higher) and shows Free Shipping, 2-8 Days Arrival, 30-Day Return and 2-Year Warranty badges near the price.