Douk Audio A5 TPA3255 Stereo Amplifier with Adjustable High-Pass Filter Review

The Douk Audio A5 is a compact class-D stereo power amplifier priced at $89.99. Built around TI's TPA3255 chip, it is aimed at bookshelf and other passive speakers in desktop, home stereo and home theater setups, and it adds an adjustable high-pass filter - a feature many budget mini amps skip.

The high-pass filter tunes from 30Hz to 200Hz, letting you trim the deepest frequencies that small drivers struggle with, which the maker says refines the mid-high range and creates a more dynamic soundstage. Under the hood it uses Post-Filter Feedback (PFFB) circuitry on a 4-layer immersion gold PCB for reduced distortion and better heat management. Measured performance is THD+N of 0.002% and SNR of 114dB or better, with a 20Hz-20kHz response within plus or minus 0.7dB. Power is supply-dependent, and Douk Audio publishes the numbers: a 32V/5A supply gives 78W+78W at 4 ohms, a 36V/6A unit lifts that to 107W+107W, and the headline rating is 300W x 2 at 4 ohms.

Inputs and outputs are simple: stereo RCA in, banana speaker jacks out, plus a 3.5mm AUX output with a 3.7V rated level for chaining another device. The tempered glass access panel on top lets you swap the two pluggable NE5532 op-amps for dual types such as 2134, 2604, 5532, 2068 or Muse02 without disassembling anything, and the transparent panel with adjustable internal LED lighting gives the small chassis some presence. Working voltage is DC 24-48V.

Douk Audio ships worldwide with free and expedited shipping options at varying cost by country. Packages under 2kg travel by airmail in roughly 10-25 days, while orders over 2kg ship via DHL/UPS/FedEx in about 5-8 days, and any import duties or customs charges are the customer's responsibility. Returns are free within 30 days for a full refund, and every item carries a 1-year warranty. Exclusions cover orders placed by mistake, man-made damage or misuse, a change of mind, and anything outside the warranty terms.