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UWAYKEY: Can an $18 Amplifier Be Any Good?

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 79 58.1%
  • 2. Not terrible (postman panther)

    Votes: 49 36.0%
  • 3. Fine (happy panther

    Votes: 6 4.4%
  • 4. Great (golfing panther)

    Votes: 2 1.5%

  • Total voters
    136

amirm

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A member asked me a while ago to test the ultra cheap ($18) UWAYKEY Mini Bluetooth Amplifier on Amazon. To make the clickbait title work :), I omitted the cost of the external power supply you need to bring yourself. What you get is a three board assembly:
UWAYKEY Mini Bluetooth Amplifier Review.jpg

UWAYKEY Mini Bluetooth Amplifier Review Boards.jpg


It took less than 5 minutes to put the heatsink on the main class D amp chip and sandwich the main board with the top and bottom. The chip used must be for smart speakers as it has voice prompts when you change inputs. Speaking of that, it has Bluetooth (which I did not test), analog and USB in. The little heatsink has no air flow and in testing, it got quite hot to touch at times.

For testing, I used my lab power supply and set the output voltage to 24 volts (max spec). The supply has 3 Amps max current. Amplifier is rated for dual 50 watts at that voltage input.

UWAYKEY Mini Bluetooth Amplifier Measurements
I started testing with analog input with volume adjusted for 29 dB gain:
UWAYKEY Mini Bluetooth Amplifier Measurements.png


Considering the price, this is not half bad:
Best cheap amplifier review.png


I kludged up a USB type A to type A cable and ran the dashboard test again:
UWAYKEY Mini Bluetooth Amplifier USB In Measurements.png


As you see performance is not as good as analog input. Worse yet, just a few seconds later, it lost stability and would no longer work reliably. If I powered it down, it would work for a second or two and then go crazy again. It may be a design issue or my setup. Either way, I could only continue with analog input testing.

Noise floor is high as you can see in the FFT graphs above:
UWAYKEY Mini Bluetooth Amplifier Measurements SNR.png


Crosstalk managed to be worse than the worst I have tested so far:
UWAYKEY Mini Bluetooth Amplifier Measurements Crosstalk.png


Multitone shows increased distortion at both ends of the spectrum:
UWAYKEY Mini Bluetooth Amplifier Measurements Multitone.png


The most important test for class D amps shows strong load dependency:
UWAYKEY Mini Bluetooth Amplifier Measurements Frequency Response.png


So the tonality you get will depend on speaker you hook up to it.

As usual, we fall way short of stated power levels:
UWAYKEY Mini Bluetooth Amplifier Measurements Power 4 ohm Stereo.png


UWAYKEY Mini Bluetooth Amplifier Max and Peak Measurements Power 4 ohm Stereo.png


8 Ohm performance was a bit better:

UWAYKEY Mini Bluetooth Amplifier Measurements Power 8 ohm Stereo.png


Response vs frequency is smooth but that may be due to high noise floor which masks distortion:
UWAYKEY Mini Bluetooth Amplifier Measurements Frequency vs Distortion vs Power 4 ohm Stereo.png


Amplifier Listening Tests
I hooked up one channel to my Infinity Reference 253 speaker and starting to listen. There was a lot more power than I expectedly, likely due to only having to drive one channel. The sound was surprisingly good until you cranked it to max volume. Speaking of which, if I paused input, the last 25% of the volume range produced tweeter hiss that was audible to about 1 meter/3 feet.

I was very satisfied with subjective performance until I landed on two clips, both of which were busy with both bass and treble notes. On these two tracks, the sound was very distorted at almost all volume levels. High frequencies would get gritty and distorted and bass response was bad as well. I power cycled the unit and let it cool and it seemed to play well for a couple of seconds and then would get distorted. It may be that the crest factor is too low causing the amp to drive hard most of the time with these two tracks. And then it overheats and distorts.

Conclusions
The first amplifier I ever built (with my brother when we were 10 or 11 years old) was this massive board and produced only 10 watts a channel. It also cost us many months of allowance. Compare that to this amplifier which for the price of a fast food meal for two, gives you stereo sound that most of the time is impressively good. If it did not distort on those two channels, I would say you could build an amp with two of them and be in business.

Given the distortion/heat issue, I can't recommend the UWAYKEY amplifier.

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As always, questions, comments, recommendations, etc. are welcome.

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amirm

amirm

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I’m disappointed. I was hoping you’d hitch it up to your Revel Salon 2’s.
There is a lot I would do for you all... That, would NOT be one of them!
 

PeteL

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The chip used must be for smart speakers as it has voice prompts when you change inputs.
I highly suspect that they are simply using the CSR/Qualcomm Bluetooth SOC as sole audio, control, and switching Interface. These chips do have rudimentary USB audio Class 1 Interface along with an analog In, and offer Voice prompts.
 

Loathecliff

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:facepalm: Yet another example of paying too much just because of the name, and getting a flawed product :rolleyes:

Before digging deep and buying an A07 I used one these for a couple of years. (edit:- chip is a tpa 3116).
With an ex-Thinkpad PS it was audibly flawless. Cost? Under £5 inc. delivery.
IMG_20220522_022256_698.JPG
 
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Chrispy

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Bottom line, for $18 it's fine. (Said in the spirit of the Poor response in the poll.....for $18 what is better?)
 
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naviivan

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Would it be better if you measure it at 1 watt instead of 5W?
 

pavuol

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If you want to extend the life of this device from 3 to 9 months, please add active cooling and use it in (untested) scenario - as a bluetooth receiver for your phone paired with active speakers :cool:
 

Blumlein 88

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Wonder how much a little fan blowing across the hot parts would help? Or perhaps just a vertical orientation may have helped with shedding heat.
 
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amirm

amirm

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Wonder how much a little fan blowing across the hot parts would help? Or perhaps just a vertical orientation may have helped with shedding heat.
It doesn't seem to need a ton of cooling. That little heatsink is not attaching itself well to the IC. And is now sandwiched between those boards they give you. Maybe cut a hole in the top PCB and put in a taller one in there.
 

Cars-N-Cans

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This reminds me of an old TDA1554 kit amp I got in the 90’s from an electroncs hobby catalog. Don’t even think the chip was even genuine. It had so much distortion at all volumes that it could easily pump out lots of “power” since the bandwidth was so limited. It just rounded all the edges off when it went into hard clipping. Great for a bass head in high school, but worst SQ ever. I’d say the $18 is too much. Yes it’s cheap, but it will be all over the place sound-wise. Maybe if it was a components and unpopulated PCB project kit I could warm up to it since there would be pedagogical value.
 

DanielT

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Thanks for your test Amir! Interesting!:)

One thing I wonder with these little cheap amplifiers, not just this one, what about the protection of the speakers? Plugging in a cheap little amplifier is just fun as long as you do not burn the speakers.:oops:
 

Blumlein 88

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It doesn't seem to need a ton of cooling. That little heatsink is not attaching itself well to the IC. And is now sandwiched between those boards they give you. Maybe cut a hole in the top PCB and put in a taller one in there.
I wonder if some thermal paste used on CPU's might help just a bit too. Sorry, just my problem solving nature. Not much reason to go too crazy on an $18 item.
 

restorer-john

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One thing I wonder with these little cheap amplifiers, not just this one, what about the protection of the speakers? Plugging in a cheap little amplifier is just fun as long as you do not burn the speakers.

They have on chip protection, but in real terms, when they fail, they will present the full output of the connected power supply to your speaker/s. Usually the PSU will shut down before smoking the woofer voice coil, but not always.

I certainly would not be connecting any speakers of value (or ones you care about) to these things.
 

DanielT

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They have on chip protection, but in real terms, when they fail, they will present the full output of the connected power supply to your speaker/s. Usually the PSU will shut down before smoking the woofer voice coil, but not always.

I certainly would not be connecting any speakers of value (or ones you care about) to these things.
So in practice speakers with about the same value, maybe some cheap used? Hm, what the hell would you like to have such a set up placed?o_O Toilets? The garage? Although a little better stuff I would at least like to have in my garage or hobby room.:)

Maybe they exist those who find the benefit of such a small super-cheap amp, but for my own part ...nop ...
 
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