AIYIMA A20 Stereo 2.1 Amplifier Review

[NTK]

Let's be realistic. You can't expect a really, seriously, super proper highpass with selectable 48 or 96 dB/oct attenuation like you would in music production software. It's still an analog circuit, and costy accordingly.

You can implement a 4th order filter with 2 opamps, i.e. one NE5532 and a few resistors and capacitors. Shouldn't cost more than USD $0.50.

 

[Sokel]

The whole point is not about subwoofers - they have a (line level) lowpass on their own, at least 90% or more of all models on the market.

The point is rather, that the highpass functionality, that is removing sub (woofer) bass from the main amp output, is the main thing that's really missing on the market. And amplifiers such as this one in the topic here address. It's a big thing, especially for very affordable devices.

Which is exactly why people like me are ending up somewhat disappointed. It's largely psychological. The expectation is big: finally! Someone makes a product with this feature! And then it is much less than perfect... omai, look at that, the power figures are exaggerated... and the highpass is set to a "puny" 60 Hz... and the delivered power turns out much less than than advertised... and look at that, pictures of a member reveal horrible build quality.

All valid concerns. All good reasons I, personally, will never consider buying this product, or recommended it to others. BUT it's still a step into the right direction.

However flawed this one may or may not be, I can still acknowledge it as a valuable stepping stone, for the Aiyima company and the whole "super budget" segment as a whole.

Draw your own conclusions as you will. In the future of hifi, good things await us.

As you all must know by now I test analog el. x-overs all the time.
I test whatever falls in my hands, be it pro, hi-fi or whatever.
A little such circuit is in this amp,

Some are nice, some not so much.
If I had to offer some experience:

- stereo pots for controlling levels is a major No, they must be of crazy quality to make it right, close to a nice pre's pots which is no cheap.

-even mono pots don't do it for precision, quality work , multi turn nice trimpots is the only way to do it down to sub-mV level and have peace of mind about precise stereo signal. That's why these cheap pro stuff like the Behri I measured at the other thread is close to useless.

-same goes for frequency settings, x-over points, etc , done through pots like the one at tht back of the OP. Drift can be even worst, and combine that with the similar quality circuit subs have and...

-nice little x-overs like that are not rocket science, you know the dirt cheap one I measured. It's the way to do it that matters. Ease is not a thing with them but you only set them once (hopefully ) and you let them be ever after.

My humble opinion is that x-over is NOT an amp's feature, far from that.
It should be always be before that, be rock-solid (specially about levels) and be so seamless that you forget is even there.

 

[surroundman]

Great amp! Please, keep adding HPF in future products too. Makes a huge difference!

 

[SMen]

Let's be realistic. You can't expect a really, seriously, super proper highpass with selectable 48 or 96 dB/oct attenuation like you would in music production software. It's still an analog circuit, and costy accordingly.

Looking back at the A70 (still) don't understand the variance from 150hz to 600hz with that model! I could understand 30 to 200 or something like that. This one starts at 60 and goes to 200 I see. I can get that being sensible, but at bass levels we are much less sensitive so going lower than 60 seems not to be a cost concern - as in this should not add additional cost.

Regarding your other points, this A20 should have completely nailed all the other good aspects of the A70 - ... that would have been progress, so I get your frustration. Loving my T20 though !

 

[Ropeburn]

As you all must know by now I test analog el. x-overs all the time.
I test whatever falls in my hands, be it pro, hi-fi or whatever.
A little such circuit is in this amp,

Some are nice, some not so much.
If I had to offer some experience:

- stereo pots for controlling levels is a major No, they must be of crazy quality to make it right, close to a nice pre's pots which is no cheap.

-even mono pots don't do it for precision, quality work , multi turn nice trimpots is the only way to do it down to sub-mV level and have peace of mind about precise stereo signal. That's why these cheap pro stuff like the Behri I measured at the other thread is close to useless.

-same goes for frequency settings, x-over points, etc , done through pots like the one at tht back of the OP. Drift can be even worst, and combine that with the similar quality circuit subs have and...

-nice little x-overs like that are not rocket science, you know the dirt cheap one I measured. It's the way to do it that matters. Ease is not a thing with them but you only set them once (hopefully ) and you let them be ever after.

My humble opinion is that x-over is NOT an amp's feature, far from that.
It should be always be before that, be rock-solid (specially about levels) and be so seamless that you forget is even there.

You're painfully poking one of my most sensitive spots I've held dearly and cherished for decades now (I guess it's called pet peeve):

Why the fuck is VCA (voltage controlled amplifier) volume control not a thing? Why the hell isn't it used everywhere by now?

It isn't complicated. It's 60s or 70s technology (at worst) in synthesizers and mixers. It's literally everywhere, and every audio engineer knows it. Once you did the (small) extra effort in design and parts cost, there's no downsides left!

Just a simple, single voltage provided by a simple mono pot (=voltage divider), controlling amplification of however many amp circuits you want. In the technically simplest and most perfect way possible. Amplification control for just two channels/destinations (stereo) should be the easiest thing ever. But somehow it isn't.

Why??

I really hope our members here with more technical design expertise can provide more insight. I really don't see the complication and hinderance of using VCAs for volume control. I assume there must be some; however they are not at all obvious to me from a cost vs use perspective. Not today when companies like Behringer can put out electronic instruments with half a dozen or much more VCAs for less than 200 moneys.

A big mystery that I would just love to see solved once and for all. I must be missing something crucial here, or else the whole fucking industry would've jumped on the whole concept long ago. What the fuck is it?

 

[Sokel]

You're painfully poking one of my most sensitive spots I've held dearly and cherished for decades now:

Why the fuck is VCA volume control not a thing? Why the hell isn't it used everywhere by now?

It isn't complicated. It's 60s or 70s technology (at worst) in synthesizers and mixers. It's literally everywhere, and every audio engineer knows it.

Just a simple voltage provided by a simple mono pot (=voltage divider), controlling amplification of however many amp circuits you want. In the technically simplest way possible. Just two (stereo) should be the easiest thing ever. But it isn't.

Why??

Probably the same reason as anything else, a separate PSU, and it must be a fairly quality one.

At applications like an x-over though, why?
You only set them once! (unless you like to play, that's another hobby) .
Have a look (the naked board) :




It usually comes with two stereo pots, I asked them to solder nothing and soldered 4 nice trimpots instead (left-upper side) .
Have a look at this post from the thread to see how nice you can match everything.




(example with filters at place)

And it's a dead cheap one, both HPF and LPF measured at the most punishing conditions (my wiring there is a total joke)
So...

 

[quocheiser]

What I will say, is that the more times you set up studios in different environments, the more the HPF comes in handy.
I can only surmise that most of the commentors here have never set up up a proper mixing or mastering environment, or tuned the sound in a club etc.
HPF is a really cool feature that gives the top speakers and the amps that drive them significant headroom and lowered distortion.
Integrating these top speakers with a sub (or multiple subs and their respective amps) becomes much easier with this very basic feature.

 

[Ropeburn]

What I will say, is that the more times you set up studios in different environments, the more the HPF comes in handy.
I can only surmise that most of the commentors here have never set up up a proper mixing or mastering environment, or tuned the sound in a club etc.
HPF is a really cool feature that gives the top speakers and the amps that drive them significant headroom and lowered distortion.
Integrating these top speakers with a sub (or multiple subs and their respective amps) becomes much easier with this very basic feature.

Please. Shut up about "most of you aren't professionals".

It's not helpful. You're just needlessly bragging for no reason, it doesn't even help whatever point you're making. There are more than enough professionals on here, none of which are as obnoxious as you suddenly decided to be since yesterday.

 

[Gibsonian]

I am using mine as tweeter amp in a high powered 3 way active triamp setup. 60 years old with typical drooping high frequency ear response. Am thinking the high frequency hump of the A20 is something my ear likes. I like this amp in this application a lot, best sounding one to date that’s been in this position

 

[Ismapics]

Can someone please elaborate on this, so I can further my understanding. If the PSU is 480 Watts (48v x 10A) and Class D is supposed to be efficient. Why do we only see 175 Watts per channel of usable power (to a dummy load). That would be 73% efficiency (175*2)/480. I maybe overlooking something here, hence my question. Is the difference on the way to 1% distortion the rest of the Watts. I want to read your thoughts.

 

[NTK]

You're painfully poking one of my most sensitive spots I've held dearly and cherished for decades now (I guess it's called pet peeve):

Why the fuck is VCA (voltage controlled amplifier) volume control not a thing? Why the hell isn't it used everywhere by now?
...

It uses an NJW1195 for volume control.

 

[KL....]

What I don't understand about the HPF - High-pass filter - is why it is required on the amplifier?
I thought that subwoofers needed to control the cross over into them ... and if using two then one independent filter for each is better than one for both.

I can understand the benefit for the main speakers and the A20 driving those ... but the 3255 chip has such power and strong damping factor anyway ... ?

Thank you, Yes, @SMen, a conundrum/dilemma, isn't it? If HPF is 2.1 (1 output/mono for 2 or more channels) then, for Mains, it needs to be <80hz (preferably <60hz, due to a loss of spatial sound and imaging detail). Although, for Nearfield Listening (like Desktop or Headphones), perhaps it can be a little higher than 80hz (<100hz, due to less loss of spatial sound and imaging detail). Nonetheless, a powered/active Sub can control and do all this with Full HL/LFE Signal (ie without HPF and for >= 2x Sub, if capable, perhaps upto 200/250hz, although Speaker Time Alignment (Main/Sub) would be required, wouldn't it, due to loss of spatial sound and imaging detail?), noteing for LFE and Sub, that they (both/together) need to Match the Amps HL/SL Gain, don't they, which is a further Complication, isn't it?

So, is HPF worth the Complication, yes, only if the Mains are (relatively) poor/average at delivering Bass (even Low Mid) Frequency and the (chosen) Sub/s can deliver the Bass (and even Low Mid) with Higher Performance. As you have mentioned, for >=80hz, the HPF/LFE/HL needs to be one HPF/LFE/HL per Sub per Channel, doesn't it, although best to do this even for <80hz, isn't it, why? Especially for the Room, being able to move the Sub/s to correct position/s, for Speaker Time Alignment (Main/Sub/Room), can be helpful (ie less/reduced room Treatment/s (perhaps even none, although unlikely), can't it?

 

[khzpv]

How much better is it than the Fosi Audio V3 (stereo)? Judging by Amir's measurements, the Fosi has better multi-tone and channel separation...

 

[SMen]

Thank you, Yes, @SMen, a conundrum/dilemma, isn't it? If HPF is 2.1 (1 output/mono for 2 or more channels) then, for Mains, it needs to be <80hz (preferably <60hz, due to a loss of spatial sound and imaging detail). Although, for Nearfield Listening (like Desktop or Headphones), perhaps it can be a little higher than 80hz (<100hz, due to less loss of spatial sound and imaging detail). Nonetheless, a powered/active Sub can control and do all this with Full HL/LFE Signal (ie without HPF and for >= 2x Sub, if capable, perhaps upto 200/250hz, although Speaker Time Alignment (Main/Sub) would be required, wouldn't it, due to loss of spatial sound and imaging detail?), noteing for LFE and Sub, that they (both/together) need to Match the Amps HL/SL Gain, don't they, which is a further Complication, isn't it?

So, is HPF worth the Complication, yes, only if the Mains are (relatively) poor/average at delivering Bass (even Low Mid) Frequency and the (chosen) Sub/s can deliver the Bass (and even Low Mid) with Higher Performance. As you have mentioned, for >=80hz, the HPF/LFE/HL needs to be one HPF/LFE/HL per Sub per Channel, doesn't it, although best to do this even for <80hz, isn't it, why? Especially for the Room, being able to move the Sub/s to correct position/s, for Speaker Time Alignment (Main/Sub/Room), can be helpful (ie less/reduced room Treatment/s (perhaps even none, although unlikely), can't it?

Yes thank you. I realize that indeed it could be useful - I run two subs, but it had become ingrained that I should assume that they would integrate with the bass roll off frequency of the main speakers ... but being able to roll these off at a higher frequency, perhaps above a port resonance for example, might well result in a better tuned combination.

So getting it / got it I think.

 

[JohnBooty]

Lol I recently bought anpther A70 for ~75 bucks to work as bi-amp. Who would buy this amp over twice the price, and with such a poor performance here

If I was in the market for an amp for a compact 2.1 system, the mains HPF would be a hard requirement so this would definitely be in the running.

 

[KL....]

Yes thank you. I realize that indeed it could be useful - I run two subs, but it had become ingrained that I should assume that they would integrate with the bass roll off frequency of the main speakers ... but being able to roll these off at a higher frequency, perhaps above a port resonance for example, might well result in a better tuned combination.

So getting it / got it I think.

Thank you, Yes, @SMen, many considerations and it is a Tuned Integration (Main/Sub/Room), isn't it :=)
As you have 2 Subs and the Mains Bass is Good Performing then integrateing the (each) Sub with the Mains bass roll off frequency is reasonable, isn't it? why? You can consider the Sub/s as a Bass Extender, or even as a Low Bass Loudness, depending on the desired/intended Integration. Should you use Loudness or Equalisation, utiliseing Subs places less Stress on the Mains Bass drivers, doesn't it? By utiliseing HL, you can connect the Subs via the Mains Binding Posts utiliseing (short) Speaker cable/long Jumpers, can't you, with no need to run long RCA/XLR cable from the Amps HPF/LFE, reasonable? The consideration needed to be considered is, does the Subs HL perform as High or Higher than the (long) HPF/LFE RCA/XLR cable, reasonable? HPF/LFE RCA/XLR, for Low Bass Frequency, the Amp can be 2.1 or 2.2 although best it is 2.2, especially as you have 2 Subs or 1 Sub has 2 inputs, reasonable?

Where Mains Bass is High/very High Performing then Subs are not necessary, are they, although as a Bass Extender, or even as a (very Low Bass Loudness), then utiliseing Subs can be considered as reasonable, can't it? Also, in this case, integrateing the (each) Sub with the Mains bass roll off frequency is reasonable, isn't it? As mentioned, this can be done via HL (usually long from Amp or Jumpers from Mains Binding Posts) or HPF/LFE (usually long from Amp), can't it?

Note that if the Aiyima a20 is SE/PSE HL/SL output then not an issue with/for an active Sub, is there? If the Aiyima a20 utilises BTL/PBTL/Balanced output then the Subs HL input must be Compatable with BTL/PBTL/Balanced Amp output, mustn't it? For BTL/PBTL/Balanced the Subs HL input must Never connect to Audio/Power Ground, why, because, for the Amp (and (possably) even the Sub), this will appear as a Short (to Ground) and (likely) damage the Amp (and/or the Sub), won't it? Just had a look at the AIYIMA A20 amplifier manual....

• Very Important.... Note that the AIYIMA A20 amplifier is a Balanced stereo power amplifier, so for a HL input, your Subs input MUST be BTL/PBTL/Balanced Compatable with the Amps BTL/PBTL/Balanced output, mustn't the Subs be?
• Noticed, No mention of this/the above in the Manual, other than HPF, and they have not suggested not to use HL?

 

[StndCpp]

The 3e Audio A5 hinted by staticV3 is significantly better in every measurement at similar cost (slightly higher), even if produces a bit less power.
I don't see why anyone would choose the A20 except if it is for the sub output or availability.

 

[pieterv1]

The 3e Audio A5 hinted by staticV3 is significantly better in every measurement at similar cost (slightly higher), even if produces a bit less power.
I don't see why anyone would choose the A20 except if it is for the sub output or availability.

I would still lean towards the 3e Audio purely for performance, but the feature set is what makes the A20 attractive. (proper 12v trig, hpf and sub output)

Nice to see that the competition doesn't sleep! Now if only they could get rid of the external power brick and make it a pure power-amp without any frontpanel controls...

 

[daniboun]

I agree, this is standard PFFB probably with cheap inductors, similar to Wiim Amp Pro (Ultra supposedly solved that) or Fosi Mono V3.

??? Wiim amp Pro / Ultra have quasi same performance. They do not have problem with PFFB

WiiM Amp Pro Streaming Stereo Amplifier Review

This is a review and detailed measurements of the WiiM Amp Pro networked streaming stereo class D amplifier. It was sent to me by the company and costs US $379. The package is minimalistic in nature and matches the "non-pro" version of the amplifier. The volume indicator is that set of LEDs...

www.audiosciencereview.com

 

[daniboun]

The 3e Audio A5 hinted by staticV3 is significantly better in every measurement at similar cost (slightly higher), even if produces a bit less power.
I don't see why anyone would choose the A20 except if it is for the sub output or availability.

Will wait for the new TOPPING MINI300 @118€

Measurements here :

TOPPING MINI300 Integrated Amplifier Black

The Topping Mini300 is a Class D stereo amplifier delivering 2x125 W into 4Ω in a fully balanced, high-efficiency design.

www.audiophonics.fr