AIYIMA A03 2.1 Channel Class D Amplifier 50W+50W+100W TPA3116 Subwoofer Bluetooth Amp HiFi Power Amplifier with Power Adapter

Received the unit quickly from Amazon. Plan to build a custom sound bar for the TV in the basement.It supports three outputs as L & R speakers and a subwoofer. Building a wood case may take some time, I decided to test the unit as a base configuration. Very easy to install and connect all required cables, included manual explained all the functionalities and operation. Just be careful about the choice of power supply. Tested with both 12V and 20V DC 5A power sources and found that with 20V DC 5A was producing more clear L/R separations with plenty of basses. The AMP is very small (palm size), and it can be easily put into the enclosure or inside of the speaker housing.Sound quality: by given size, it is far better than similarly priced AMP. Clear separation and better sound stages.Build Quality: Good, cannot see any issuesVolume and other knob controls: all precisely workingHeat issue: Getting worm, but, no issuesBluetooth function: Easily sync and nice sound quality compared to the direct connection, within workable ranges (about 10 meters), no issuesThis is one of affordable & the best HiFi amp at the given price.

I had real low expectations when i bought this little amp. The first power source i tried was a 19v laptop power supply and it sounded pretty good hooked up to a pair of bookshelf speakers and then even better with a pair of Transmission Line speakers I have. It was during the COVID lockdowns so i had way too much free time on my hands and i decided to make this amp as good as possible. First thing I did was replace the no-name caps on the PCB. Followed by a proper 24v 8a power supply made by CUI (meanwell equivalent) which really improved the sound due to the higher voltage and amp capability. I was building some drawers for my closet at the time and had some scrap birch plywood and 1/4" Walnut boards and made those into an enclosure. Some perforated sheet metal for a bottom,and a piece of sheet metal (painted) for the top. The plate for the controls is 1/8" aluminum and the labels were made using laser transfer paper. I extended the antenna to an SMA connector using some coax to the rear of the amp for a proper antenna as well as wired up some RCA jacks for the line-in. Some cheap speaker terminals and a small 5v sunon fan to keep everything cool.One thing to note, this amp makes a lot of noise if you don't run a wire that loops around each of the threaded part of each volume knob, and grounding that wire. The other thing i don't like is the switch for x.1 mode. It is a low pass filter for just the sub channel, and doesn't remove the low bass from the L and R channels. Ill be making a crossover for my speakers when i have the time since they've got small drivers and don't like all that bass.

Positive side: Dead quiet. Excellent sound. I have installed with a high quality linear supply at 21VDC and using line input where source is audiophile grade Oppo player and speakers are $10k+. Also worked fine with 19vdc 5amp laptop supply. Compares well with any priced power amplifier where a clean 20 watts is all you need. Noiseless controls. Treble control has proper shelving. Decent hardwire connections. Great option for a DIY portable player or mini system. Insane good sound and features for $30!Negative side: PCB had rosin residue. This should have been cleaned off. Unit seems to mute when signal is extremely low. Long quiet fadeouts on recordings get chopped. If player is turned off then on in a short time span, it will not accept line in mode. It seems to want a 20+ second off cycle to reset and behave normally. Threads on controls not long enough for faceplates thicker than 1/8". Subwoofer channel has poor design decisions. Low pass control 80 - 250hz is only 6db slope. Control should allow for lower low pass crossover point like down to 40hz.

This is a very good board, better than others I've tried. Sound quality is great for the price. My cargo van turned camper had no tunes- this was super easy to install, and very efficient which is a concern when camping off grid. Have it running a pair of 6x9 coaxial speakers in the doors, and a 12" sub behind the seat. Rocks hard when I want to crank it up.l, sounds good at lower levels too. Signal to noise ratio is better than some of the others brands I've tried, and no annoying popping or cranking.Bluetooth pairing is very quick and easy. Better than most anything I've tried. Havent really tested the range yet.I like that it comes with adjustable bass and treble levels and crossover frequency.Runs great on the nominal 12 volt automotive electrical system- no need for an extra power supply to step up voltage unless you just want to blast it crazy loud. I like loud music and It's PLENTY loud and crisp for me.Since this is so efficient, I plan on buying another one for use in the off grid house to hook up to a pair of higher end house speakers for home theater sound, with the laptop for my tv.