Aiyima’s new balanced amplifier- A20

[Fxfighter]

I also want to refer to the HPF function here... it's a big advantage for 2.1 desktop setups (mainly made using small monitors with low bass performance coupled with a medium size subwoofer). HPF could make the big difference in this scenario. Such feature is not something to be overlooked.

So... I'm eagerly awaiting Amirm's review as well.

24 db/ octave HPF

 

[Schlippwhip68]

Ok A20 owners be careful of your RCA connection. It’s a serious weak spot on this amp. The work Aiyima put into the PCB board and overall design has been literally nullified through one small area of poor part choice. The RCA is super flimsy and any decent plug with good grip just may pull the sleeve out with it when removing the cable. If you look closely you will see how pathetic the retaining design is. It is literally a ribbed grip and that’s all it is. It could not get any cheaper, what a waste!
Why would someone skimp here when this often is a high use area? The entire RCA bracket is incredibly weak. My A70 is rock solid here with no play at all, no movement anywhere. I have had to return the A20. This is my second Aiyima product return this month. The first was an A70 with ridiculous channel imbalance which got so bad within 1 month that even when turned all the way down music was clearly coming through the left channel at about 15db. The A20 went down within 1 month too,

 

[Schlippwhip68]

As tempting as it is, politely ignoring this sort of inanity is how audio communities turn into cesspits of golden-eared $3000 USB cable cork-sniffers, and I would hate to see ASR turn into that.
Op-amps are not "bold", "musical", "detailed", "reserved", "bloated" etc. This is just fundamentally nonsensical (even if we neglect the quite ludicrous idea that a linear device more-or-less doing its job can create complex perceptual effects, as opposed to the mundanity of distortion and noise) - we can grant an op-amp *might* have (non-illusory) audible effects if you put them in a slot where it starts to oscillate or have exorbitant amounts of distortion or otherwise misbehave (which is hardly unlikely when people mindlessly swap circuit components), but this is not intrinsic to the op-amp, it is always a matter of what the op-amp is doing in the circuit.

Well matey, just think of it like this, a few billion ears disagree with you and not just some members of one website so all best trying to convince those ears of your claims from a post on ASR!
As far as I am concerned you have more chance of fooling me by telling me Coke Cola has no bubbles in it and Milk is really blue.
Cheers!

 

[Ropeburn]

Well matey, just think of it like this, a few billion ears disagree with you and not just some members of one website so all best trying to convince those ears of your claims from a post on ASR!
As far as I am concerned you have more chance of fooling me by telling me Coke Cola has no bubbles in it and Milk is really blue.
Cheers!

If the mass argument had any merit, we'd all be eating shit. Because trillions of flies can't be wrong.

 

[oleg87]

Well matey, just think of it like this, a few billion ears disagree with you and not just some members of one website so all best trying to convince those ears of your claims from a post on ASR!
As far as I am concerned you have more chance of fooling me by telling me Coke Cola has no bubbles in it and Milk is really blue.
Cheers!

I'm not terribly concerned with what laypeople with zero relevant technical background think about electronics, theoretical physics, medicine, etc.

And to be clear, I'm not trying to convince anyone who throws out whoppers like this and only digs in on it:

Ok, there is no such thing as placebo effect when rolling op amps.

If you believe this, you are not capable of having a serious discussion about audio. This is like if an astronomer subscribed to geocentrism- if your view on the topic is so fundamentally wrong-headed, you are not going to get very far.

 

[Schlippwhip68]

If the mass argument had any merit, we'd all be eating shit. Because trillions of flies can't be wrong.

Flies eat waste/dung out of choice, not necessity.

 

[Gibsonian]

I’ll be the counter on this one. RCA’s still attached and playing as good of tweeter music I’ve heard. I like it!

 

[Schlippwhip68]

I'm not terribly concerned with what laypeople with zero relevant technical background think about electronics, theoretical physics, medicine, etc.

And to be clear, I'm not trying to convince anyone who throws out whoppers like this and only digs in on it:

If you believe this, you are not capable of having a serious discussion about audio. This is like if an astronomer subscribed to geocentrism- if your view on the topic is so fundamentally wrong-headed, you are not going to get very far.

Blue Milk.

 

[antcollinet]

Blue Milk.

You know that both the bubbles in coke, and the colour of milk can be measured, don't you?

This is the point at which you get muted.

 

[Ropeburn]

Ok A20 owners be careful of your RCA connection. It’s a serious weak spot on this amp. The work Aiyima put into the PCB board and overall design has been literally nullified through one small area of poor part choice. The RCA is super flimsy and any decent plug with good grip just may pull the sleeve out with it when removing the cable. If you look closely you will see how pathetic the retaining design is. It is literally a ribbed grip and that’s all it is. It could not get any cheaper, what a waste!
Why would someone skimp here when this often is a high use area? The entire RCA bracket is incredibly weak. My A70 is rock solid here with no play at all, no movement anywhere. I have had to return the A20. This is my second Aiyima product return this month. The first was an A70 with ridiculous channel imbalance which got so bad within 1 month that even when turned all the way down music was clearly coming through the left channel at about 15db. The A20 went down within 1 month too, View attachment 491719

Just what happened to me the other day:

25 year old DJ mixer. I guess it's excused at that age; however a new device isn't. Not with 25 years of improved logistics and production of cheap parts between them.

 

[Schlippwhip68]

Just what happened to me the other day:

View attachment 491889

25 year old DJ mixer. I guess it's excused at that age; however a new device isn't. Not with 25 years of improved logistics and production of cheap parts between them.

25 years use is not bad, has the edge over 1 month. I used to have a PMC 17a back in the 90s with a pair of 1210’s. Vestax built great mixers to be fair.

 

[AIYIMA]

Ok A20 owners be careful of your RCA connection. It’s a serious weak spot on this amp. The work Aiyima put into the PCB board and overall design has been literally nullified through one small area of poor part choice. The RCA is super flimsy and any decent plug with good grip just may pull the sleeve out with it when removing the cable. If you look closely you will see how pathetic the retaining design is. It is literally a ribbed grip and that’s all it is. It could not get any cheaper, what a waste!
Why would someone skimp here when this often is a high use area? The entire RCA bracket is incredibly weak. My A70 is rock solid here with no play at all, no movement anywhere. I have had to return the A20. This is my second Aiyima product return this month. The first was an A70 with ridiculous channel imbalance which got so bad within 1 month that even when turned all the way down music was clearly coming through the left channel at about 15db. The A20 went down within 1 month too, View attachment 491719

We’re very sorry for the inconvenience caused. If you encounter any product issues, please feel free to contact our customer service team and we’ll assist you as soon as possible.
Thank you as well for your feedback — we are already optimizing the design of the RCA connectors.

 

[Guddu]

We’re very sorry for the inconvenience caused. If you encounter any product issues, please feel free to contact our customer service team and we’ll assist you as soon as possible.
Thank you as well for your feedback — we are already optimizing the design of the RCA connectors.

@AIYIMA
Have there been more such reports of the same issue with A20?

 

[caught gesture]

@AIYIMA
Have there been more such reports of the same issue with A20?

It happened to me as well but I put it down to my own error. I had not loosened the locking interconnect cables properly. It was an easy matter to just push the connector back in place and it hasn’t caused any further problem. I made the same mistake on my previous DAC and that was definitely not a budget model (North Star Design) from almost twenty years ago. Once again I pushed the connector back in place and never had another problem.

 

[ziggurcat]

Review is up:

AIYIMA A20 Stereo 2.1 Amplifier Review

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). The A20 is the most elegant design I have seen from the AIYIMA. Not only is it stylish, it also...

www.audiosciencereview.com

 

[Schlippwhip68]

It happened to me as well but I put it down to my own error. I had not loosened the locking interconnect cables properly. It was an easy matter to just push the connector back in place and it hasn’t caused any further problem. I made the same mistake on my previous DAC and that was definitely not a budget model (North Star Design) from almost twenty years ago. Once again I pushed the connector back in place and never had another problem.

Yes, I tried the same thing as I just did not want to return the amp to Aiyima! I committed to the upgrade path with the T20 included and liked the overall sound and look of this set up.

I pushed the sleeve back in but unlike your model, the whole RCA board was loose and not just the sleeve. It’s a very flimsy implementation of a cheap plastic unit behind the back plate. The sleeve also remained loose after replacing. I only removed the RCA around 3-4 times over a month and they were not supper grippy plugs like WBT for example, those thing grip like a Pit Bull! These are Audioquest solderless plugs and have a good grip at medium strength. Nothing out of the ordinary in that regard.

It’s good to see Aiyima chirp in and not shy away from any criticism and better to see a confession towards the shortcoming in design and endeavouring to improve it. That’s the way forward imo.

 

[Mark185]

I originally posted to Amir's thread where he measured the Aiyima A20 where I reported measuring the HP filter as having a 6 dB/octave rolloff slope. I think that should have been posted here where users report their experience so from now on, this is where I will post. I have a Quant Asylum QA403 analyzer. It is not as accurate and capable as Amir's Audio Precision equipment but it is still very capable and these QA403's are used all over the world for audio testing. In my original post, I measured frequency response acoustically with the A20 driving small sealed enclosure speakers. What follows are measurements taken with the QA403 and the A20 amplifier driving a 4 ohm non-inductive resistor bank. Pictures of my test equipment are included. The oscilloscope picture shows the output stage switching frequency with no input signal. At ~500mV and 456 kHz, I believe this to be very good filtering of the switching frequency in the A20 design. (I measured this without a Class D amplifier filter which I suspect Amir uses with his Audio Precision rig.)

Frequency response plot with blue trace is with an 80 Hz high pass filter switched on. Red trace with with no high pass filter. Last trace is THD plus Noise vs Frequency at various power levels with the 80 Hz filter on. Things to note:

1. I tested with volume control bypassed using the A20 as an amplifier and used RCA outputs. I will need to make some custom cables to test the balanced outputs.
2. Blue trace clearly shows 6 dB per octave rolloff with 80 Hz high pass filter setting.
3. Red trace shows that frequency response is very flat from 10 Hz to 20 kHz and beyond with the high pass filter switched off.
4. THD + N plots show 1% at 20 Hz falling to 0.1% at 100 Hz with the 80 Hz high pass filter switched on.
5. At frequencies above 100 Hz, with filter on, THD + Noise is commendably low falling to ~ 0.01% range by 6000 Hz and continuing to fall up to 20 kHz.
6. Last picture is screen shot of QA403 measurement of THD+N at 1000 Hz and maximum gain setting on A20 amplifier. These numbers are very good.

• Bottom line for me is this is a very good performing basic amplifier. I just feel they missed the mark with how they implemented the high pass filter. 12 dB/octave Butterworth would match up nicely with sealed box small speakers if you matched it to the speaker's Fb (resonant frequency) and F3. Putting 2 Butterworth filters in series gives a Linkwitz Riley 24 dB/octave acoustic response. (I am well aware that if the main speakers and subwoofer(s) are not phase aligned, the summation will not be true L-R 24 dB/octave but that technical discussion is beyond the scope of this thread.)
• I think the most effective use of the 6 dB/octave high pass is to use it with small sealed speakers and set it between 150 - 200 Hz depending on your speakers' Fb and F3. That will augment the natural 12 dB/octave rolloff of the closed box.

 

[caught gesture]

I originally posted to Amir's thread where he measured the Aiyima A20 where I reported measuring the HP filter as having a 6 dB/octave rolloff slope. I think that should have been posted here where users report their experience so from now on, this is where I will post. I have a Quant Asylum QA403 analyzer. It is not as accurate and capable as Amir's Audio Precision equipment but it is still very capable and these QA403's are used all over the world for audio testing. In my original post, I measured frequency response acoustically with the A20 driving small sealed enclosure speakers. What follows are measurements taken with the QA403 and the A20 amplifier driving a 4 ohm non-inductive resistor bank. Pictures of my test equipment are included. The oscilloscope picture shows the output stage switching frequency with no input signal. At ~500mV and 456 kHz, I believe this to be very good filtering of the switching frequency in the A20 design. (I measured this without a Class D amplifier filter which I suspect Amir uses with his Audio Precision rig.)

Frequency response plot with blue trace is with an 80 Hz high pass filter switched on. Red trace with with no high pass filter. Last trace is THD plus Noise vs Frequency at various power levels with the 80 Hz filter on. Things to note:

1. I tested with volume control bypassed using the A20 as an amplifier and used RCA outputs. I will need to make some custom cables to test the balanced outputs.
2. Blue trace clearly shows 6 dB per octave rolloff with 80 Hz high pass filter setting.
3. Red trace shows that frequency response is very flat from 10 Hz to 20 kHz and beyond with the high pass filter switched off.
4. THD + N plots show 1% at 20 Hz falling to 0.1% at 100 Hz with the 80 Hz high pass filter switched on.
5. At frequencies above 100 Hz, with filter on, THD + Noise is commendably low falling to ~ 0.01% range by 6000 Hz and continuing to fall up to 20 kHz.
6. Last picture is screen shot of QA403 measurement of THD+N at 1000 Hz and maximum gain setting on A20 amplifier. These numbers are very good.

• Bottom line for me is this is a very good performing basic amplifier. I just feel they missed the mark with how they implemented the high pass filter. 12 dB/octave Butterworth would match up nicely with sealed box small speakers if you matched it to the speaker's Fb (resonant frequency) and F3. Putting 2 Butterworth filters in series gives a Linkwitz Riley 24 dB/octave acoustic response. (I am well aware that if the main speakers and subwoofer(s) are not phase aligned, the summation will not be true L-R 24 dB/octave but that technical discussion is beyond the scope of this thread.)
• I think the most effective use of the 6 dB/octave high pass is to use it with small sealed speakers and set it between 150 - 200 Hz depending on your speakers' Fb and F3. That will augment the natural 12 dB/octave rolloff of the closed box.

Thank you for this testing. I’m left wondering why Aiyima is claiming a 12dB/octave filter as they designed and implemented the HPF. I’ve asked them again on the other thread for clarification. @AIYIMA

 

[Tontom]

Hello AIYIMA, what do you say ?

 

[Mark185]

I suspect this is a problem for Aiyima. The A20 is a flagship product for them. Any criticism is bound to cause problems for someone in their company. I do think it is worth repeating. The basic amplifier is very good.