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AIYIMA A07 TPA3255 Review (Amplifier)

amirm

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This is a review and detailed measurements of the AIYIMA A07 desktop amplifier based on TPA3255 class D amplifier chip. It was kindly purchased new by a member and drop shipped to me. The cost is US $72 on Amazon including prime shipping. And as of this shipping, it also included a 32 volt, 5 amp switching power supply. Member also purchased and sent me a 48 volt/3 amp power supply which I also tested.

The case is standard budget audio affair:
AIYIMA A07 TPA3255 Review.jpg


The volume control feels cheep but does the job. The back panel terminals were way too small for my binding posts:

AIYIMA A07 TPA3255 Review back panel RCA.jpg


The DC input socket was quite stiff especially with the 48 volt power supply. Tightness is not a bad thing as far as power transfer is concerned but this was a bit too stiff. Here are the two power supplies:

AIYIMA A07 TPA3255 Power Supply.jpg


They both feel kind of cheap as they would be at these prices ($21 for the 48 volt one). Personally I would not leave these plugged in permanently if I am not around. The included power supply has a two-pronged AC cable that was not polarized. Rotating it around made a small difference in mains leakage.

AIYIMA A07 Measurements
Let's start with our usual dashboard of 5 watts into 4 ohms:
AIYIMA A07 TPA3255 Measurements 32v 5 amp power supply.png


As you see in the FFT display, there is considerable amount of mains leakage at 60 Hz. This tends to be a function of switching power supplies. I played with grounding and improved it a lot in one channel but not in the other (not shown). SINAD did not get impacted since it is bound by distortion harmonics. As it is, performance is above average:
best desktop stereo amplifier review.png


Signal to noise ratio is not great due to the mains hum:
AIYIMA A07 TPA3255 Measurements 32v 5 amp power supply SNR.png


Frequency response is well behaved, albeit with a slight droop at 20 kHz:

AIYIMA A07 TPA3255 Measurements 32v 5 amp power supply Frequency Response.png


Crosstalk is good and well above bargain basement desktop amps:
AIYIMA A07 TPA3255 Measurements 32v 5 amp power supply Crosstalk.png


Power is everything in a small amp so let's see how we do with 4 ohm load:

AIYIMA A07 TPA3255 Measurements power into 4 ohm.png


As expected, with low impedance of 4 ohm we are current limited so the 5 amp stock power supply does better, turning in 77 watts. Yes, the 300 watt rating is a fantasy but maybe it can do better with momentary peaks. Alas, its aggressive protection circuit would shut it down and not let me test max and peak power.

Naturally the higher voltage power supply does better with 8 ohm load where we become voltage limited:
AIYIMA A07 TPA3255 Measurements power into 8 ohm.png


Sweeping power vs frequency and distortion shows a very well behaved class D amplifier:
AIYIMA A07 TPA3255 Measurements power into 4 ohm vs frequency and distortion.png


Conclusions
Traditionally these desktop amplifiers have produced really poor performance in the form of noise and distortion. Not so anymore. These TPA3255 based amps seem to have good bones in them, producing above average performance for peanuts. Alas, you are saddled with two boxes and cheap and potentially non-safety compliant parts. For desktop use, these are probably acceptable compromises.

I am going to recommend the AIYIMA A07 based on its performance.

And with this, our last review of 2020 comes to an end! Nice that it is ending on a happy note. :)

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

Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

TheWalkman

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Amazon is running an 8% coupon on these so for $66, it looks like I’ll get a late stocking stuffer for Christmas. How many of these little Class D amps should you have? N +1, of course.

Looks like I’m already starting 2021 off by continuing bad habits. So much for New Year’s resolutions. :facepalm:
 
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amirm

amirm

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Great review, thanks!

So, this is how you're preparing for the new year's fest, Amir? Don't you ever take some days off. :)
Original plan was to take a week off. Then I got hit with a bunch of requests to finish reviews of gear that had been sent so here I am. :) The only excuse is that I am waiting for midnight to usher the new year. A bit more than an hour to go!
 

xykreinov

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Very nice. I'm glad to see another contender in this rather noncompetitive price range.
I am looking for an amp under $200 that has both above average SINAD performance and high power. So far, nothing comes all too close to a used Niles SI-275. The AIYIMA has comparable SINAD to the Niles. But, with much lower power than the Niles, of course.
 

wwenze

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Hope this good review doesn't open a can of worms, that people will be asking for more reviews of similar amps. At this price point there is bound to be 50% good value and 50% garbage.
 

pavuol

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Thank you for another great review and all the fantastic year (yes 2020 was fantastic at ASR :))

Some thoughs:
Amazon listing says recommended power adapter DC48V 5A, while manufacturer's product page recommends even higher (48V 7,5A). So question arises if we reached max. potential here..

I'd be curious about the thermal design as well. Maybe it wouldn't cost much time (with these cheap "easy to remove cover" bricks) to measure the heatsink temperature near max. output (with infrared thermometer). Say not every amp review, from time to time..;)
That said, I wonder if these passive chip-amp designs are more limited with overall hw design or with internal temperature. (and if it will go higher in output, had it be active cooled)

PS: listening tests shouldn't be omitted, mfg claims at product page "dual 300W shocking bass output" ;)
 
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Bruce Morgen

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The power supplies used for this test just aren't beefy enough for the chip to perform to its potential. Forget those wimpy little "power bricks" provided and/or recommended by eBay and AliExpress sellers -- they're barely adequate to light up the front panel LED (OK, I'm exaggerating a bit). This little gem needs to be reevaluated with a 48VDC 7-10A SMPS -- provided with sufficient DC muscle, this little gem can pound like Thor's hammer and sing like a world-class soprano!
 

Bruce Morgen

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Amazon is running an 8% coupon on these so for $66, it looks like I’ll get a late stocking stuffer for Christmas. How many of these little Class D amps should you have? N +1, of course.

Looks like I’m already starting 2021 off by continuing bad habits. So much for New Year’s resolutions. :facepalm:

If you're patient enough, you can get one for less than $50 shipped from Aiyima's AliExpress storefront, "Yimaglobal Store."

Aiyima-Owned AliExpress Store listing for the A07
 

Bruce Morgen

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- high noise floor
- high mains hum residuals
- high order distortion components in the spectrum
- low BW with roll off at 20kHz

Why is this recommended? Because it is small and Class D? Are there any specifications limits for recommended components? And why not?

I've come to see over time that Amir's recommendations have tried to take price/performance ratio into account. It's absurd to expect a sub-$100 power amp to be evaluated by the same standards as a counterpart costing five or ten times more -- I'm sure this thing wouldn't rate a very happy panther if it was priced like a Purifi-based or Benchmark product approaching or exceeding four figures at retail.
 
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