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AIYIMA A70 Stereo Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 12 3.1%
  • 2. Not terrible (postman panther)

    Votes: 39 10.1%
  • 3. Fine (happy panther)

    Votes: 189 49.1%
  • 4. Great (golfing panther)

    Votes: 145 37.7%

  • Total voters
    385
Thanks!

The DAC I plan to pair with it is the SMSL SU-1, which lists a 47 ohm output impedance. So it should be even more favorable than the numbers you list here. (If I'm following your math correctly, a 1% voltage reduction with two amps instead of the 0.5% voltage reduction it would be with one amp.)

What if the second amp has a much higher input impedance? (I believe my other amp is 23 kOhm)
Then the voltage drop will be a little less. You'll have 23K in parallel with 10K = 6.97K. 47ohm ouput impedance, and you have 47/6970+47 = 0.67% voltage drop.


Bottom line : as long as input impedance (combined if driving more than one device) is at least 10x the output impedance of the source, you'll have less than 1dB voltage drop - and that is fine. Just turn the volume up 1dB if you think it matters.
 
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Then the voltage drop will be a little less. You'll have 23K in parallel with 10K = 6.97K. 47ohm ouput impedance, and you have 47/6970+47 = 0.67% voltage drop.


Bottom line : as long as input impedance (combined if driving more than one device) is at least 10x the output impedance of the source, you'll have less than 1dB voltage drop - and that is fine. Just turn the volume up 1dB if you think it matters.
Awesome, much appreciated.
 
Thanks for the review. A bit late reply/reaction. New in the low budget class d game. To me this product segment look like a fine solution to build affordable active open baffle speaker using fullrange drivers and supported with different dipole, bipole or cardiod LF solutions. You asked if the freq plot from the offered sub out is usefull? Yes Sir. It is nice and helpfull. Just as the behaviour of the filter would be when driving a LF driver…….maybe not relevant for most readers but at least for us DIY building speakers. Thank again. Rgs Mike Dane
 
Thanks for the review. A bit late reply/reaction. New in the low budget class d game. To me this product segment look like a fine solution to build affordable active open baffle speaker using fullrange drivers and supported with different dipole, bipole or cardiod LF solutions. You asked if the freq plot from the offered sub out is usefull? Yes Sir. It is nice and helpfull. Just as the behaviour of the filter would be when driving a LF driver…….maybe not relevant for most readers but at least for us DIY building speakers. Thank again. Rgs Mike Dane
It would help if you quoted the person you were replying to.
 
I'm about ready to grab one of these, reading a few reviews online I came across this one that explains the sounds as,

"Smooth and romantic sound"

"The presentation is smooth and laid back, relaxed"


Is there any truth to this? It's contrary to a lot of other opinions and reviews out there, I really want something neutral and transparent, devoid of character.
 
I'm about ready to grab one of these, reading a few reviews online I came across this one that explains the sounds as,

"Smooth and romantic sound"

"The presentation is smooth and laid back, relaxed"


Is there any truth to this? It's contrary to a lot of other opinions and reviews out there, I really want something neutral and transparent, devoid of character.
It's poetic hifi speak, it only takes on meaning for you if you can hear what the writer was hearing through the system they were listening to. At that point you, yourself, might describe it using completely different words.
 
It's poetic hifi speak, it only takes on meaning for you if you can hear what the writer was hearing through the system they were listening to. At that point you, yourself, might describe it using completely different words.
I agree that these kinds of reviews are unhelpful; however, to try to answer your question I did try out this amplifier and I would characterize its overall sound as neutral to cool. The problem I had with it is that the acoustic orchestral instruments I normally listen to sounded wrong and that's why I returned it.
 
I'm about ready to grab one of these, reading a few reviews online I came across this one that explains the sounds as,

"Smooth and romantic sound"

"The presentation is smooth and laid back, relaxed"

Is there any truth to this? It's contrary to a lot of other opinions and reviews out there, I really want something neutral and transparent, devoid of character.
I have an A70 and have been very pleased with it. I had a class A power amp prior to this (Schiit Aegir) and in my system i don't hear any difference between the two other than the A70 has more power (but I don't listen loudly so not much of a big deal on that point.) I like the A70 as it is small and runs very cool and has a 12 volt trigger -- in short, it makes my system easier to use with no sacrifice of sound quality. It's not the prettiest amp out there, but I have mine sitting out of the way and control the volume with the control on my WiiM Ultra.
 
I agree that these kinds of reviews are unhelpful; however, to try to answer your question I did try out this amplifier and I would characterize its overall sound as neutral to cool. The problem I had with it is that the acoustic orchestral instruments I normally listen to sounded wrong and that's why I returned it.
Such reviews are of course nonsense. Unfortunately your own personal perception will also apply only to you - is most likely coming purely from perceptive bias or lack of controls - and even if not will not inform anyone else how they will perceive the sound.
 
Just a heads up for anyone using the A70 stereo XLR inputs.
I'm using the A70 as an additional amplifier to bi-amp some floorstanders.
As I'm in the UK the land of pin 2 hot ...I've had to reverse pin 2 and 3 it was out of phase for me.
Using the unbalanced inputs there has been no noise powering up or down, however using the XLR inputs there is a low level click/pop.
This is utilising the 12v trigger.
Otherwise all good.
10A psu.

This post is quoted from the owners thread, before I hit buy on this could I clarify from anyone if there is any truth to this, I will be using this in the UK and I've never heard of the "pin 2 hot" in the UK before?

When using the XLR input on the A70, will the phase be correct?
 
This post is quoted from the owners thread, before I hit buy on this could I clarify from anyone if there is any truth to this, I will be using this in the UK and I've never heard of the "pin 2 hot" in the UK before?

When using the XLR input on the A70, will the phase be correct?
Hi, pin 3 hot (+) is standard in the USA , so I doubt there'll be a UK , pin 2 + version. Just use an adaptor or reverse polarity on the loudspeaker cables .
 
I have some problem with my A70. It sends some high pitch noise to speakers when it's powered up. I've recorded and these 2 frequencies showed in spectrum.
noise.jpg


It's interesting that noise completely disappears when volume is set to maximum. Amplifier works perfectly then and speakers are completely silent.
A70 is connected to S.M.S.L. M300SE by XLR cables, and M300SE receives input by USB cable. I can control the volume on M300SE so it's not a big deal, but I would like to figure out where the problem is. I didn't have this problem when I used AIYIMA A300 as amplifier in the same setup.
 
I have some problem with my A70. It sends some high pitch noise to speakers when it's powered up. I've recorded and these 2 frequencies showed in spectrum. View attachment 427194

It's interesting that noise completely disappears when volume is set to maximum. Amplifier works perfectly then and speakers are completely silent.
A70 is connected to S.M.S.L. M300SE by XLR cables, and M300SE receives input by USB cable. I can control the volume on M300SE so it's not a big deal, but I would like to figure out where the problem is. I didn't have this problem when I used AIYIMA A300 as amplifier in the same setup.
Have you implemented any op-amp changes, or had it fitted with non stock op-amps? If so, change back.

Is this noise with nothing connected to the input of the amp? If so, what happens if you short circuit the input (pin 2 to pin 3)

If your SMLS is still connected, then does the noise still happen with it disconnected?
 
No changes, just freshly arrived from manufacturer.
When nothing is connected there is no noise. Haven't tried shorting inputs.
When SMSL is connected but turned off, there is no noise, but there is a big pop when powering on/off amp. SMSL tends to cause pops by itself when powering on/off so I usually keep it on all the time and just power on amp when I'm listening.
 
No changes, just freshly arrived from manufacturer.
When nothing is connected there is no noise. Haven't tried shorting inputs.
When SMSL is connected but turned off, there is no noise, but there is a big pop when powering on/off amp. SMSL tends to cause pops by itself when powering on/off so I usually keep it on all the time and just power on amp when I'm listening.
OK - that sounds like the noise is coming from the SMSL or upstream of that. What is driving the SMSL? What happens to the noise if you disconnect that?


Are you measuring the noise with a microphone? Are you able to measure the outputs from the DAC electrically?


EDIT - since this is the review thread, and the Mods like us to keep such threads just for the review discussion we should take this technical issue elsewhere.

Can you create a new thread for it in the amps (or dacs) section and link it back here. I'll then copy my replies into that thread.
 
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SMSL is driven by MacBook connected over Thunderbolt 4 dock which also supplies power to both MacBook and SMSL. I've tried connecting SMSL directly to MacBook over usb cable and in that case there is still noise. I've also tried using toslink cables from dock to SMSL and powering SMSL by USB charger, and in that case there is still noise.
I was just measuring noise with iPhone's microphone because I wanted to get the frequencies. Unfortunately can't measure it electrically.
I'm just wondering why noise disappears completely and system is working perfectly when amp is set to maximum volume. With A300 I didn't get noise at any volume level with the same setup.
 
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