Audio Amplifier Board, Icstation Ḅḷụẹ-ṭọọṭḥ-Compatible Stereo Audio Amplifier Module 2x5W BT 5.0 Mini Amplifier Board 3.7V 5V for DIY Speakers

Summary:Great value for a dual mode, USB + Bluetooth audio module. Good performance of output power versus distortion. Bluetooth pairs and maintains connection well with both Android and iOS sources, and presents good wireless performance in crowded RF airspace and distances of at least 40 feet of line of sight.Packaging and included parts:The module comes in a static-safe bag, with supplied connectors for left and right speaker, and a battery. On all 3 connectors, one side is a JST 2-pin plug, and the other is bare wire, intended to be soldered on to a battery and speaker terminals.Given the height of the plastic connectors, and a relatively large electrolytic capacitor (not surface-mount), I would have liked to see some crush/impact cushion like foam or bubble-wrap. However, since Amazon usually ships with their own impact cushioning envelopes or box filling, I don’t see this as a big negative (though I would encourage the vendor to add some packaging to err on the side of caution)The bare wire and connectors are fairly flexible and robust, and I had no trouble soldering them to terminalsComponents and physical board:The module consists of some passive components and 3 main ICs:* JL AC19AP1R101 - Zhuhai Jieli Technology Co., Ltd Bluetooth ICThere is not much data about this chip online. It does seem to be a popular BT IC found in many Chinese manufacturer’s products* (2x). NS4165B - 5W Mono, AB/D Class Dual mode audio amplifierThis one has a full data sheet available online.The board itself appears well laid out with appropriate grounding and solder connections, especially on the connectors, were solid. There was no sign that the connector solder points were cold/loose or prone to breakage even with moderate pulling force applied to the connectors.The module claims to support a Li-Ion/Li-poly battery, directly connected to the battery terminals on the module, and that it can charge that battery when itself is connected via USB.Performance:For the purposes of evaluation, the module was connected to two general purpose (wide-range) 4 inch speakers, 4 Ohms and about 10W maximum power handling. Power was provided by the computer in the USB Audio case, and a USB battery pack (capable of 2+ Amp output) in the Bluetooth case.No Li-Ion battery was attached directly.* USB AudioThe module enumerates itself as a generic audio device, with the name “JieLi BR21”. Querying capabilities shows support for a single playback mode, 16-bit, 48000HZ.Playback from various applications within Windows 10 was trouble free without stuttering. Varying volume was smooth and linear across both channels. Multiple plug/unplug was without issues.* BluetoothBluetooth functionality was tested with (1) an iPhone running iOS 13.1.3, and an a OnePlus 5 (Android) phone running Android 9. Both phones paired immediately with the module. Connection was stable in an environment with 6 different 2.4 Ghz channels in moderate use (WiFi). I tried it at line of sight distances up to 40 ft., and a single wall obstruction at around 30 ft. In both cases, playback continued without noticeable stutter or disconnections.Disconnecting the module from power and reconnecting - causing a BT reconnect - also worked flawlessly from both phones.On the downside, the module doesn’t seem to support APTX (the protocol for high def. audio over Bluetooth); I have used the OnePlus 5 with APTX compatible receivers and can confirm it supports it; it was unable to make the same type of connection with this module. However, I won’t consider this as a negative since it was never advertised as supported, and really it would be incredible for a module in this price bracket to support it (I believe Qualcomm charges fees for the use of APTX)* Audio outputSound presentation was clean using music with a wide spectrum. There was some clipping at the upper end of the volume range, but well within expectation for this type of module (and the amplifier used), and it is difficult - with my test setup - to attribute how much the speakers themselves contributed.The module is fairly sensitive to noise; Switching from a USB battery pack to a standard “USB charger” (the kind you plug into the wall to charge a phone), resulted in considerable noise to the output. On an oscilloscope, intermittent spikes of up to 200 mV were seen, when input was clamped to 0v.On clean power from the USB battery pack, noise spikes were less than 50 mV, and spurious (not periodic). This is fairly respectable for a module in this class.(Audibly, this was imperceptible on my test speakers)Playing back pure sine and square waves yielded fairly accurate waveforms on the scope, even at high output levels; the remained relatively consistent as power varied. There was some overshoot and distortion, but again it’s well within what I expect from this class/price-bracket of audio module.And again, in practice, the sound of the music used as test source was very clean and more than acceptable for most things one would use this module.Other notes:* The audio outputs are independent and do not share common signals; do not attempt to tie the negative (-) terminals together, in order for example, to connect to a set of speakers using a 3.5 mm Tip-Ring-Sleve (with a common ground; these usually feed into an amplifier anyways, and the signal in this case is amplified already).* Current draw from the USB port went beyond 1 Amp at high volume levels, but even with several minutes of playing, the 2 amplifier ICs remained only moderately warm.* I did NOT have a chance to test the Li-Ion battery connector/source, nor the charging capabilities of the module.VERDICT:5 Stars.

Fantastic little cheap easy solution for decent sound. Had a pair of old computer speakers that the amp inside was bad, 4ohm 4 watt from 2004 per label on them. Decided to try this to make the speakers useful, repurpose if you will. Ingredients: using one of those cheap portable battery chargers for cell phones from local w-mart and this adaptor with the speakers, some thin wire, a single pole switch and soldering iron and hot glue for the project.Pretty straight forward, solder the power line to pins 1 and 4 on the portable battery usb type A output, this is your 5 volt dc and ground if unsure which pins look it up on web very straight forward. Took the 5 volt side from battery to switch. Other side of switch to the adaptor. (Your on off) You could go fancy here with a switch that lights up or a separate led to indicate on / off but the blue light on the adaptor is bright enough that if you mount it right you can see its on. (Tip, flexible clear plastic would direct this light to speaker cover with a pin hole to let it shine thru just glue in place, its what I did- think fiber optic) Solder the left and right speakers for positive and negative. I would not use common ground (shared negative) because I don’t think this amp is biased for that setup. Used tape to hold inside speaker then hot glued in place. Mounted the battery pack so can plug in to charge by cutting a hole backside bottom. Sounds great on my iPad, paired right up. Volume is controlled in your device. Loud enough I usually set at about 60%. Battery says 2200mah, I get about 4-5 hours per charge so very satisfied.This all said a few comments: soldering is easy enough with the proper gear. Your going to struggle if you use a cheap iron with a big tip or poor solder. I used a rather simple 60 watt adjustable temp pencil type with a rather fine point and standard 60/40 tin/lead solder. (About 30-40$ on amazon for a kit) Wire go stranded/braided not solid but keep it thin say 16-18 gauge. This not high powered and no need for heavy wire nor room to connect it. Most of the cheap on the go battery packs will work that are designed to give you extra juice for cell phone. Usually the big USB port (type A) is power out to charge your phone and the smaller mini is to recharge the battery pack. So if you go this route like I did just keep in mind the size vs what your putting it in. Have fun, great little project, took me about 2 hours making it all look like “off the shelf”.