AIYIMA A20 Stereo 2.1 Amplifier Review

[Mark185]

i did not realize you had those skills to do it with your PC. That is excellent!

 

[fwwwk]

Thank you for the detailed reply.

So thinking about the DSP angle it suddently occured to me that I'm using a computer and my pc has extra outputs!

So an hour or so of reading later I came up with the following...
I cut apart a spare 3.5mm to 3.5mm cable and spliced in a pair of RCA plugs since I didn't have another 3.5 to rca cable. A quick check with the multimeter showed that i had soldered it up correctly and there were no shorts.

Tip -> White
Center ring -> Red
Bottom ring -> Ground on both plugs

Hooked it up to the Sub. Put the phase back to 0 (will need to verify this but it sounds right to my ear). Put the sub in LFE mode.

Went into windows and configured it as a 5.1 system. Critically here I lied to windows and told it that i had all of the speakers connected. I did not want windows doing the 5.1 downmixing. I wanted to handle that myself.

Did a bunch of reading on how to down mix the center and rear channels into 2.1.

Wrote a script in APO to handle downmixing and set the crossovers on the speakers and sub. (see attached)

It sounds great. Nice deep punchy bass and male vocals don't sound weird on youtube anymore. Maybe not on par with what the Wiim does with room fit but at least now I can separate the speakers from the sub. So I should be able to fix it up with another round of measurements and filters in REW.

Thanks again.

Can you elaborate why 5.1 mixing is superior in this case? IMHO key is to play with offsetting LPF on your sub and HPF on Aiyima A20 and you should be able to integrate more or less with trial&error method

 

[thompsbp]

Can you elaborate why 5.1 mixing is superior in this case? IMHO key is to play with offsetting LPF on your sub and HPF on Aiyima A20 and you should be able to integrate more or less with trial&error method

It's not superior. Unfnortunately windows doesn't support configuring the onboard adudio as 2.1. Its either 2.0, 5.1, 7.1, or quadriphone. So if you want a sub you have to pick either 5.1 or 7.1, otherwise the LFE output won't be available in APO. 5.1 is just easier to downmix back to 2.1.

The problem I had specificially was that no matter what i did with the filters I just could not get the bass response i wanted.

The A20 has an always on 200hz lpf on the sub out. So if i want to set my crossover at 80hz i have to stack two analog filters. 200hz at the amp and 80hz at the sub. This has a big unpredictable effect on the phase and the delay between the speakers and the sub. I spent probably 4 hours over the weekend adjusting the phase knob on the sub and taking measurements. Most of them showed huge holes in the 80-120hz region (-9db). A few showed minor improvements. When a did find a result that gave me the kick i was looking for in that range it played hell with male vocals.

Also the HPF on the A20 is rather anemic. Setting it a 80hz I still saw a lot of cone movement at 50-60hz. I know thats not very scientific but when I used the WIIM AMP PRO on the same speakers/sub there is hardly any cone movement in the same range.

I would really have preferred that the A20 either not put a 200hz lpf on the sub out and instead just let me control it with the lpf on the sub or tie the lpf to the HPF. That would probably have worked just fine.

Applying DSP at the OS level of my computer is not what I want to do (cause i also dual boot into linux). But for now I can live with it if it means not having fork out several hunderd more $ and I am currently learning the linux audio stack so I can replicate on that side.

 

[Mark185]

@thompsbp you may want to look into using Camilla DSP. It can run on Windows, Linux and MacOS. It is very powerful software if you understand how to use it and have a decent sound card or external USB audio interface.

CamillaDSP

 

[Mark185]

CamillaDSP - Cross-platform IIR and FIR engine for crossovers, room correction etc

I would like to announce CamillaDSP, a general purpose tool for routing and filtering sound. It can be used for example for building crossovers for active speakers, or for performing room correction. You can find the source code here: GitHub - HEnquist/camilladsp The documentation for all...

www.diyaudio.com

 

[PacketofCrisps]

I wonder how something like this genuinely competes against the likes of a NAD C399? It's hard to wrap your head around with it being this cheap and small, your brain says it has to be vastly inferior!

 

[thompsbp]

I wonder how something like this genuinely competes against the likes of a NAD C399? It's hard to wrap your head around with it being this cheap and small, your brain says it has to be vastly inferior!

It has its problems for sure as have been documented here. If I had known what the sub out and hpf really were I would not have purchased it. I basically had to stop using the features that I bought it for.

I ended up returning mine and getting the Wiim amp pro instead.

 

[fwwwk]

The sub out is a low pass filter. 200 Hz low pass filter on the A20 is less than 2 octaves away from the likely subwoofer filter setting on the Bronze W10. That is too close and the two filters will interact. My guess is the bass will be 'muddy' with a one note boom and not much clarity. There is also a strong possibility that the 900 mV max output from the A20 sub out will not be enough to drive the Bronze W10 to the desired volume because the two filters interacting will attenuate the signal more than if only the subwoofer's built in filter was used.

Optimum would be to use either the A20 subwoofer out to drive an active sub with no filter on the sub or do it the way I described above and use both the XLR and RCA outputs from the T20 to drive the high pass amplifier and the subwoofer separately. The advantage of my recommendation is the low pass filter on the sub and high pass filter on the Aiyima A20 can be adjusted separately.

There is no way to predict the effect of plugging the port on the bookshelf speakers. (Actually, if I knew the Thiele-Small parameters of the Monitor 6" driver and the cabinet volume, I could predict it.). Woofers designed for a ported alignment are not usually also equally suited to a sealed enclosure. I base this on 40 years of designing and building my own speakers. My guess is plugging the port on the Bronze bookshelf speakers will result in a mild acoustic roll off below 120 Hz with a Q in the range of 0.4 - 0.5. That may sound good but no way to know without actually trying it and measuring.

https://manuals.plus/ae/1005009979773040

this manual claims sub out voltage is 2V so really most typical you can get, once again we need @AIYIMA clarifications

 

[Mark185]

https://manuals.plus/ae/1005009979773040

this manual claims sub out voltage is 2V so really most typical you can get, once again we need @AIYIMA clarifications

900 mV measurement is RMS. Peak voltage is closer to 2 Volts but not quite there. I don't use the sub out so have not pursued this further.

 

[Fxfighter]

https://manuals.plus/ae/1005009979773040

this manual claims sub out voltage is 2V so really most typical you can get, once again we need @AIYIMA clarifications

Unbelievable. I connect T20 rca to MA W10, xlr to A20. Both set at 100hz cutoff. Big improvement. Thanks.

 

[Mark185]

Unbelievable. I connect T20 rca to MA W10, xlr to A20. Both set at 100hz cutoff. Big improvement. Thanks.

I believe that you are using the Aiyima preamp and amp in the most effective way possible!

 

[Fxfighter]

I learned a lesson. T20 both rca xlr get signal simultaneously. It's a magic. Thanks.

 

[Chanur]

What would be a good alternative to this amp? The pics have me iffy on the build quality here.

 

[fwwwk]

Exterior Build quality is exceptional, interior i cant say but dont see significant amount of claims here

 

[pieterv1]

What would be a good alternative to this amp? The pics have me iffy on the build quality here.

If you can live without the Subwoofer output, then obviously the Topping Mini 300 or 3e Audio A5

 

[Mark185]

If you can live without the Subwoofer output, then obviously the Topping Mini 300 or 3e Audio A5

The subwoofer output is deeply flawed in that it is fixed at 200 Hz. Agree Topping Mini 300 and 3E Audio A5 are alternatives worth looking at but the A5 has gone up in price considerably and is currently $279 on Amazon. The A7 is only $20 more and that would be my choice in this price range. The Mini 300 is very interesting in that it is priced well below the A20. When Aiyima puts the A20 on sale for ~$150 I think it is a good value.

 

[Chanur]

The subwoofer output is deeply flawed in that it is fixed at 200 Hz. Agree Topping Mini 300 and 3E Audio A5 are alternatives worth looking at but the A5 has gone up in price considerably and is currently $279 on Amazon. The A7 is only $20 more and that would be my choice in this price range. The Mini 300 is very interesting in that it is priced well below the A20. When Aiyima puts the A20 on sale for ~$150 I think it is a good value.

Are you saying the A20 is locked at 200hz or the A5?

 

[thompsbp]

Are you saying the A20 is locked at 200hz or the A5?

A20 is.

 

[rebbiputzmaker]

A20 is.

I don’t see the problem that you’re claiming. If you have a powered subwoofer with crossover and everything, why would that matter? With a steep slope from the subwoofer say at 80 hz, you’ll be down 18 to 24 dbs + by the time you get 200 Hz. Have you really heard such poor matching? Obviously, they could run the sub out full range, but practically they did not need to. Thats why they didn’t do it. Would probably be a simple mod if somebody really wanted to.

 

[rebbiputzmaker]

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.

Maybe I’m confused, are you talking about a $4000 amplifier or $150 amplifier? I think maybe some people expect too much for their money. The product is a great sounding value product. Anybody who thinks differently is in my opinion being very unfair.