AIYIMA A20 Stereo 2.1 Amplifier Review

[thompsbp]

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.

I could not get the sub and the speakers to integrate properly. I always had a huge hole in the crossover frequency. From what I have read double stacking analog filters like that (200hz at the a20 and 80z at the sub itself) can make the phase do really weird non predictable non linear things. I'm still relatively new to this so I am not saying I was even doing it right... but whatever the WIIM AMP Pro does for integration is great and measuring it there is no hole.

 

[rebbiputzmaker]

I have been measuring some small speakers with my A20 and compared response with and without the high pass filter. The change in low frequency roll off for small speakers that naturally roll off around 200 Hz is very slight looks to me like the Aiyima A20 high pass is only 6 dB per octave. Given that the speakers are already rolling off below 200 Hz I am not 100% confident in my estimate that the amplifier has a 6 dB/octave filter. Need to investigate more. If it is 6 dB, then that is just a simple capacitor/resistor network getting switched in and out.

The filter is audible and does improve the sound of very small speakers like the Cambridge MinX 22 but to be honest, I think I will want 12 dB/octave or better for my final solution. I am going to try a Dayton Audio DSP-408 I own and use the amp full range. Long story short, I am beginning to question just how useful the Aiyima high pass filter really is. I understand the DSP-408 costs more than the A20 but it does allow for much more complex crossover schemes and adds parametric EQ too.

If I was buying an amplifier today, I would choose the 3e Audio A7 or Fosi V3 mono dual set as both are on sale for Black Friday for around $239. Yes it is a fair bit more than the A20 sale price but these are better amplifiers and for me, the difference between ~$150 and ~$239 is not that much given the higher performance of the 3E and Fosi amps. I had hopes that the A20 would be in the same performance range as these two other models but it is not.

An in-line capacitor would be 6dbs. An RC or LC network would be 12.

 

[Mark185]

An in-line capacitor would be 6dbs. An RC or LC network would be 12.

I suggest you read the whole thread. I did determine that the high pass is indeed 12 dB/octave and I apologized to Aiyima because my initial posts were wrong. I stand by my comment that the subwoofer output is flawed because it is fixed at 24 dB/octave with no adjustment possible. Stacking that with an active sub 80 Hz filter will give a poor result. The sub output would be better for most users if it had no filter. I also stated that the A20 is a fine sounding basic amplifier with low noise and low distortion when the filters were all bypassed. I based my multiple comments on my ears, my measurements, and my experience as an electrical engineer. I apologized to Aiyima because as an EE, I should have known better than to publish erroneous comments without examining my measurements more thoroughly.

The Wiim AMP Pro does do a better job of integration because it has DSP capability to adjust low and high pass filters and parametric equalizer to improve in room response. It is in a completely different price range but offers value for the extra $$. I own a Wiim Ultra preamp and have experimented with using it with quite a few different amplifiers with good results.

 

[rebbiputzmaker]

I just read all of the thread and I did see you mention that. But what you can do is use a different slope on the subwoofer to help blend it better. For example, 12 dbs at 80hz. Not a perfect solution, but it would fill in more, you still might have phase issues, possibly making it harder to tune the system. They could easily modify the amp and just let it run full range. It would be interesting to hear their rationale for the design. The funny thing is that this stuff does sound so good, but they’re still budget components. I think some people here when they discussed these components overlook how inexpensive they are. They stopped looking at every side joint and bent lead on the circuit board. Although I’m less crazy than I used to be, I still have a collection of equipment. When they were on sale during the holidays, I picked up the T and A 20s. Hooked up a pair of LS 50s I had laying around as a third system, and it sounds really amazing. All I did with the preamp was put in a pair of Tele smooth plates, and set the amp to full volume. It did not sound as good in the bypass mode. IMO. My current main amps are currently Purifi and Hypex. Still have some tube amps packed away, but this stuff is less hassle.

 

[Gibsonian]

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.

Yes it’s a very good sounding amp imo.

 

[Mark185]

I agree that buyers need to recognize that this generation of inexpensive chip amplifiers compare very favorably with venerated amplifiers from several decades ago that were considered budget audiophile pieces and at prices that are orders of magnitude lower. I own Hafler XL280, Adcom GFA-5500, and Apt Holman One amplifiers that are all in excellent condition. The Aiyima A20 does not have the headroom of those Class A/B amps but is not far off the mark unless I am cranking the volume way past normal listening levels.

Less hassle is a big deal at my age as I downsize. I also have a B&K AV6000 in my home theater setup that weighs ~60 lbs and can also function as a space heater. Replacing that with 6 channels of TPA3255 amplifiers is very feasible and something I will probably do in 2026. I will use the A20 for 2 channels and probably DIY a 4 channel amp using some well regarded 3255 boards that were reviewed by Guntar Smits on YouTube.