AIYIMA A20 Stereo 2.1 Amplifier Review

[delta76]

tear down video
the one who is in charge or product naming at Aiyama should be punished. Absolutely no logic between product names ...

 

[JSmith]

This is a review and detailed measurements of the AIYIMA A20 stereo class D amplifier with high-pass filter.

Thanks for checking this one out Amir.

Not too bad...

Yeah for the price, it's decent... could be better though.

Let's look closer at a retail unit;

JSmith

 

[capslock]

@JSmith What the hell is that red unsoldered cable doing there?

 

[JSmith]

@JSmith What the hell is that red unsoldered cable doing there?

The wires to the speaker terminals have been desoldered from the rear panel. It's just the way the pic looks, but is just the middle wire coming under the right one and sticking up.

JSmith

 

[Sokel]

I didn't check the price (I rarely do) but even 10 euro is too much for a load depended amp these days, no matter what.

IMD is like an ominous forest compared to other desktop amps.
One would guess that everyone should have mastered a ten years old chip, at the dawn of the rumored upcoming new one.

Thanks Amir!

 

[Sokel]

...and here's a great advertisement for "My First Cheap Soldering Kit" with the extra flux uncleaned.
Is this a joke?

 

[daniboun]

It looks like a Chinese amp, anyway.

 

[JSmith]

I wondered how long it would be before someone mentioned this... wasn't long!

I thought this was a bit average as well;

JSmith

 

[Chr1]

It seems to fall a fair bit short of the quoted power specs

With the 48v10A power supply, measured performance was ~178W into 4 ohms (at 1% THD)
That's even less than the quoted power for 8 ohms and miles away from the claimed 250w into 4 ohms.

This is the norm for these little desktop amps though surely?

Just don't buy expecting anything like the claimed power.

I'd love to see a list of those, whose power claims are accurate...A very short list, I'd bet .

 

[Sokel]

I wondered how long it would be before someone mentioned this... wasn't long!

I thought this was a bit average as well;

View attachment 492057


JSmith

Other spots as well.
But these two were eye-poppers!

 

[DearSX]

Hope this amp is reliable cause connected to a WiiM, with some DIY Mechano speakers and a nice subwoofer and you have we have ourselves a great little HiFi system for under $400 (not counting the sub).

Now what would be a good subwoofer amplifier (non plate)? Or I can just pick up a used SVS subwoofer online.

 

[SlowJim]

What's up with the Sub Out port? Is there some kind of white cap that covers it?

 

[Mark185]

I purchased this amp at full price over a month ago and have to say, I am a bit disappointed in the test results. I expected better for $197 given the marketing info Aiyima put out there. I will say the high pass filter is very useful for desktop speakers if an active sub is also used. I am using mine with a pair of Cambridge Audio Minx 22 speakers and a DIY powered subwoofer. In this application, the A20 works well and the high pass filter makes a noticeable difference in the sound of the Minx 22 speakers, Not what I consider high fidelity but for a computer desktop use case, it gets the job done. I do not think the distortion is audible in my use case and at the current sale price, I think this amp is worth it. I do prefer the 3E Audio A7 amp especially at its Black Friday price of $239. I own one of those and use it in a 2.1 system in my TV room with a Wiim Ultra and a powered SVS sub. FWIW my reference system is an Apt Holman preamp and Apt One power amplifier.

Doing a near field measurement with a Umik1 mic and REW, I do see the high frequency rising response that Amir measured. I doubt it is audible but it is measurable,

 

[trevor_bartram]

If you know your speaker impedance rises at ultrasonic frequencies, will the addition of a capacitor across the speaker terminals be sufficient to tame the peak?

A20 example, where C = 1 / (2*PI*f*Z), for f = 40KHz & Z = 8 Ohms, C = 0.47uF?

 

[StefanC]

The old A70 had better test results across the board. A70's crosstalk is much better. A bit more power, too, but no high pass filter and bypass.

 

[NTK]

If you know your speaker impedance rises at ultrasonic frequencies, will the addition of a capacitor across the speaker terminals be sufficient to tame the peak?

A20 example, where C = 1 / (2*PI*f*Z), for f = 40KHz & Z = 8 Ohms, C = 0.47uF?

The importance of load dependency, IMHO, is completely overblown. Below is the CTA-2034 spinorama plot for the KEF Blade 2 Meta obtained from spinorama.org. See that there is a ~4 dB roll off in the listening window measurement from 10 - 20 kHz? In comparison, the deviation between the 4 Ω and 8 Ω frequency response at 20 kHz for this amp was less than 1 dB. I get that the fix (PFFB) is easy and costs nothing. But the problem is a small one.

If you want to "optimize" the output filter by adding parallel capacitance, TI has an Excel spreadsheet tool you can play with. But since adding capacitance is just going to lower the LC output filter cutoff (resonance) frequency and therefore moves the resonance peak to a lower frequency, it is likely counter-productive.

LCFILTER-CALC-TOOL Design tool | TI.com

View the TI LCFILTER-CALC-TOOL Design tool downloads, description, features and supporting documentation and start designing.

www.ti.com

 

[JDS]

This is a review and detailed measurements of the AIYIMA A20 stereo class D amplifier with high-pass filter. It was sent to me by the company and is on black Friday sale for US $157 (normally $195).
View attachment 491991
The A20 is the most elegant design I have seen from the AIYIMA. Not only is it stylish, it also has quite a bit of weight to it (for its class). The amp has both RCA and XLR balanced inputs which you can easily select with the switch on the right. It took me a bit to figure out that to activate high-pass filter, you push the toggle switch up a notch past "ON." Nice way to save a switch and still get the job done, allowing the design to look balanced.

Back panel shows everything you wanted but perhaps, had not managed to get in this class of amplifier:

View attachment 491992
OK, maybe not the giant, 10 amp 48 volt power supply. There is trigger input and of course, its high pass filter which you set with that knob. I like that it has detents and is rather stiff so you don't turn it by accident. You can bypass the volume control by pressing that button for a few seconds. In testing, I did not find a performance difference between using that, or setting the volume to max.

AIYIMA A20 Amplifier Measurements
I started with volume set by pass and high pass filter disabled using XLR input:
View attachment 491993
Distortion is kept quite low so noise sets the SINAD (more or less). At nearly 94 dB, this is excellent performance:
View attachment 491994
View attachment 491995
It is awfully close to our blue range despite the diminutive size and cost. You lose a bit of performance as usual if you use RCA:
View attachment 491996

Here is actual noise performance which again for the class is excellent:
View attachment 491998

Despite implementation of PFFB, there is a slight load dependency:
View attachment 491999
And that general peaking. High pass works as advertised.

Multitone and 19+20 kHz tests show the typical behavior of rising distortion in upper ranges:
View attachment 492000
View attachment 492001

Channel separation is better than average (for all amps):
View attachment 492002

The beefy power supply turbo charges the amplifier, producing a lot of power in such a small package with 4 ohm impedance:
View attachment 492003
View attachment 492004

It is able to maintain that close to bottom of hearing range at 40 Hz:
View attachment 492005

8 Ohm output is of course diminished but still respectable:
View attachment 492006

As noted, high frequencies are the enemies of this platform:
View attachment 492007

Amplifier was stable on power on:
View attachment 492008

It does however potentially have a power on/off pop:
View attachment 492009

Conclusions
It is amazing how far we have come in this category of amplifier. AIYIMA was one of the earliest adopters producing performance that was hard to imagine at the time. In A20, it has managed to bring more and more refinement as to define a new class here. Yes, there are a few minor misses like flatness of frequency response but generally, you have a very power full amplifier, with low noise and mostly, low distortion. Combine it with good looks and nice functionality such a proper high pass filtering for subwoofer use and you have a winner here.

I am going to recommend the AIYIMA A20 stereo amplifier.
------------
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/

Highly performant, cheap and cool-running little amps like this are why I wish there were more good AV pre-processors out there at reasonable prices.

 

[Guddu]

This is a review and detailed measurements of the AIYIMA A20 stereo class D amplifier with high-pass filter. It was sent to me by the company and is on black Friday sale for US $157 (normally $195).
View attachment 491991
The A20 is the most elegant design I have seen from the AIYIMA. Not only is it stylish, it also has quite a bit of weight to it (for its class). The amp has both RCA and XLR balanced inputs which you can easily select with the switch on the right. It took me a bit to figure out that to activate high-pass filter, you push the toggle switch up a notch past "ON." Nice way to save a switch and still get the job done, allowing the design to look balanced.

Back panel shows everything you wanted but perhaps, had not managed to get in this class of amplifier:

View attachment 491992
OK, maybe not the giant, 10 amp 48 volt power supply. There is trigger input and of course, its high pass filter which you set with that knob. I like that it has detents and is rather stiff so you don't turn it by accident. You can bypass the volume control by pressing that button for a few seconds. In testing, I did not find a performance difference between using that, or setting the volume to max.

AIYIMA A20 Amplifier Measurements
I started with volume set by pass and high pass filter disabled using XLR input:
View attachment 491993
Distortion is kept quite low so noise sets the SINAD (more or less). At nearly 94 dB, this is excellent performance:
View attachment 491994
View attachment 491995
It is awfully close to our blue range despite the diminutive size and cost. You lose a bit of performance as usual if you use RCA:
View attachment 491996

Here is actual noise performance which again for the class is excellent:
View attachment 491998

Despite implementation of PFFB, there is a slight load dependency:
View attachment 491999
And that general peaking. High pass works as advertised.

Multitone and 19+20 kHz tests show the typical behavior of rising distortion in upper ranges:
View attachment 492000
View attachment 492001

Channel separation is better than average (for all amps):
View attachment 492002

The beefy power supply turbo charges the amplifier, producing a lot of power in such a small package with 4 ohm impedance:
View attachment 492003
View attachment 492004

It is able to maintain that close to bottom of hearing range at 40 Hz:
View attachment 492005

8 Ohm output is of course diminished but still respectable:
View attachment 492006

As noted, high frequencies are the enemies of this platform:
View attachment 492007

Amplifier was stable on power on:
View attachment 492008

It does however potentially have a power on/off pop:
View attachment 492009

Conclusions
It is amazing how far we have come in this category of amplifier. AIYIMA was one of the earliest adopters producing performance that was hard to imagine at the time. In A20, it has managed to bring more and more refinement as to define a new class here. Yes, there are a few minor misses like flatness of frequency response but generally, you have a very power full amplifier, with low noise and mostly, low distortion. Combine it with good looks and nice functionality such a proper high pass filtering for subwoofer use and you have a winner here.

I am going to recommend the AIYIMA A20 stereo amplifier.
------------
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/

Thank you @amirm
Wondering if you have thermal scan for the temperature like you did for other amplifiers?

 

[F1308]

I can't understand that recommendation.
I can't understand that rating.

 

[phoenixdogfan]

Great review, Amir. The high pass is a wonderful feature since most powered subs today don't have one anymore. This would make a great pairing with the ASCI C6b's. Should be possible to add a DAC with remote volume control for around $100, and have a complete nearly fully range system for l.t. $1500. Still have to be careful about what sub you add, since there's nothing on the A20 to compensate for a sub with DSP that adds significant group delay. But for $157 clearly a steal.