3e audio A7/A7 Mono Amplifier Review

[RandomEar]

All im saying is that we are FAR away from understanding what truly happens in our ears and brains, once they get hit with varying wavelength and frequency vibrations. Standard measurement practices cant measure ALL different factors here. Amir always measures with a steady-spectrum. And a combined 32-sine-wave signal is still a steady-state measurement, even if people here like to ignore that fact. Music is NOT!

Edit: And here I am, debating again...

Message to golden-eared audiophiles posting at ASR for the first time...

Hello friend. Hey, listen...we know how it is. Believe me, most of us have been there too. You've spent years toiling in the muck of audiophilia. You read ALL the reviews. You watched ALL the youtube videos. You visited ALL the other forums where everything always makes a difference. You...

www.audiosciencereview.com

 

[NTK]

... And a combined 32-sine-wave signal is still a steady-state measurement, even if people here like to ignore that fact. Music is NOT!

Can you explain what is so steady about this? Does the amplifier, DAC or whatever see this, will immediately realize that this is just a multitone test signal, and enters a more relaxed state and therefore will perform better (better means of course only from the point of view of the measuring intrumentation), because it "knows" this is an "easy" signal to deal with, unlike "music"?

 

[Hindsider85]

Can you explain what is so steady about this? Does the amplifier, DAC or whatever see this, will immediately realize that this is just a multitone test signal, and enters a more relaxed state and therefore will perform better (better means of course only from the point of view of the measuring intrumentation), because it "knows" this is an "easy" signal to deal with, unlike "music"?
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Allow me to retort in the simplest of terms.
Have you ever seen a single piece of music that has such a pattern? Show me a single one. This is not applicable to real world usage. Not at all. It simply isnt and there are tons of sites and articles, who refuted this style of measurement years ago and do not even engage with it. Amir is not the single authority in this space, even if a lot of people here like to assume that.

 

[NTK]

Allow me to retort in the simplest of terms.
Have you ever seen a single piece of music that has such a pattern? Show me a single one. This is not applicable to real world usage. Not at all. It simply isnt and there are tons of sites and articles, who refuted this style of measurement years ago and do not even engage with it. Amir is not the single authority in this space, even if a lot of people here like to assume that.

No music has the same repeated waveform pattern either. So if an amplifier "works well" for one piece of music, we'll still have no idea how it performs with the next, or the one after that?

 

[Dave TR3A]

All im saying is that we are FAR away from understanding what truly happens in our ears and brains, once they get hit with varying wavelength and frequency vibrations. Standard measurement practices cant measure ALL different factors here. Amir always measures with a steady-spectrum. And a combined 32-sine-wave signal is still a steady-state measurement, even if people here like to ignore that fact. Music is NOT!

Edit: And here I am, debating again...

Oh no! Not this again.

 

[antcollinet]

All im saying is that we are FAR away from understanding what truly happens in our ears and brains

But we are very well able to understand the limitations of the detector aparatus that can send those signals to our brains. And once the levels of difference are too small for the apparatus to detect - then there is nothing being sent to the brain for us to lack understanding of what happens to it. Our ears have neither infinite sensitivity - nor infinite bandwidth - and they are surprisingly bad at detecting different frequencies - especially when those frequencies are close together.

In other words - when our ears are unable to detect the difference - they can't send that difference to the brain - and it matters not one whit - how well or how badly we understand what the brain does. Cos it's got nothing to do it with.

 

[antcollinet]

Thats why discreet solutions of varying types CAN alter/affect the sound. Why do you think many people, prefering a certain style of music, prefere Bursons or Staccatos or Sparkos etc.? Because their different designs correspond well with different styles of music. Even if a NE5532P "measures" the same as a Sparkos, with Amirs style of testing, I can assure you that they do NOT sound the same with music.
And neither does the OPA1612 in comparison to the Burson V6V in my set-up, with the 3E A7. I can vouch for that, because I tested both.
Have you ever heard any OPA at all? Or are you trusting Amir more than your own ears? If so...well...That is your perogative. It certainly isnt mine nor that of many others.
Not anymore. I also "trusted the science". Not anymore. Going forward, I will ONLY trust my own ears.

JFC it's relentless.

Your "impressions" are meaningless until you test blind and properly controlled. The brain - which you fully admit is a mysterious organ of wonder - is far too good at making shit up that isn't in the sound reaching your ears.

So if you only trust your ears you need to do exactly that. Compare blind - and not use your eyes, or foreknowledge to allow your brain to change what you hear, based on what you know you are listening to.

Have you ever seen a single piece of music that has such a pattern?

The exact same pattern - of course not. Just as no two songs are exactly the same.

This though - My Sharona, by The Knack - looks visually similar. Such that an amp has no way of knowing that one is music and the other is a test signal. The amp doesn't care - it just amplifies - and distorts and adds noise. It does this to music in exactly the same way it does it to a test signal. It is why test signals work.

 

[Shotgun Rico]

I purchased the 3e a7 stereo version with the 10a power brick. It fed my JBL 4410a’s beautifully. I’m not sure what that means but I used the OG WiiM amp at 60 watts and was complacent. The 3e a7 on the other hand made them shine. The low end came alive.

 

[Argentum 05]

Hello everyone.
I own two A7 mono amplifiers with OPA 1612 amplifiers. They have two separate 48V/10A power supplies.
I've been using a Yamaha AX 892 amplifier for many years. I bought it new in 1997, right after it came out.

I've had the A7 for about three months now. I'd like to share a brief comparison and hear the opinions of other owners of A7s and similar models.

I bought the A7 to finally listen to Class D amplifiers, compare them to my Yamaha, and try passive horizontal biamping, with an eye toward active biamping with DSP in the future.
I was considering choosing between two options: high-frequency, mid-range, and low-frequency amplification.
My speakers: 1) Yamaha NS 700X (output terminals are divided into HF, MF, and LF)
2) DIY speakers based on NOEMA full-range drivers and Beyma cp 12 tweeters, vented box, tuned to 64Hz.

Source: WIIM Pro Plus

Test track: The Sheffield Lab Drum & Track Disc

My subjective impressions: The Yamaha AX 892 has better treble. The sound of metal cymbals is longer and more varied. The 3e A7 reduces and somewhat impoverishes these sounds. Or is it just my Yamaha that distorts the sound (?) and I like that...
I liked the low frequencies better with the A7. But the difference wasn't that pronounced. In a blind test, I probably wouldn't have been able to tell the difference.
In the midrange, I didn't notice any difference.

I repeat, this is a SUBJECTIVE opinion. I wasn't able to conduct full-blown blind tests with instant switching, so I found pronounced high-frequency performance on the test track, listened to a 15-20 second section multiple times, then switched the speaker cables to a different amplifier, and listened to the corresponding sections of the track again.
I compared the low frequencies in the same way.
Incidentally, when listening to music as a whole, I couldn't tell these amplifiers apart.

I'd like to hear the opinions of other A7 owners (and similar models) who also use, or have previously used, AB amplifiers.

I'm using Google Translate for this text. Please excuse any semantic errors associated with this.

 

[RandomEar]

Test track: The Sheffield Lab Drum & Track Disc

My subjective impressions: The Yamaha AX 892 has better treble. The sound of metal cymbals is longer and more varied. The 3e A7 reduces and somewhat impoverishes these sounds. Or is it just my Yamaha that distorts the sound (?) and I like that...
I liked the low frequencies better with the A7. But the difference wasn't that pronounced. In a blind test, I probably wouldn't have been able to tell the difference.
In the midrange, I didn't notice any difference.

With all due respect, but if you wouldn't hear a difference in a blind test, that means there isn't one to begin with. Well done blind tests are free of bias and more sensitive to audible differences than sighted listening.

I repeat, this is a SUBJECTIVE opinion. I wasn't able to conduct full-blown blind tests with instant switching, so I found pronounced high-frequency performance on the test track, listened to a 15-20 second section multiple times, then switched the speaker cables to a different amplifier, and listened to the corresponding sections of the track again.
I compared the low frequencies in the same way.
Incidentally, when listening to music as a whole, I couldn't tell these amplifiers apart.

I'd like to hear the opinions of other A7 owners (and similar models) who also use, or have previously used, AB amplifiers.

You already mentioned the long switching time, which is understandable in a home setup without a dedicated speaker switcher. But it is still very problematic for such a test where you would expect essentially no difference to begin with. Even more important though: Did you level match the amplifiers and if so, how?

 

[Argentum 05]

With all due respect, but if you wouldn't hear a difference in a blind test, that means there isn't one to begin with. Well done blind tests are free of bias and more sensitive to audible differences than sighted listening.


You already mentioned the long switching time, which is understandable in a home setup without a dedicated speaker switcher. But it is still very problematic for such a test where you would expect essentially no difference to begin with. Even more important though: Did you level match the amplifiers and if so, how?

The WIIM PP volume level was set, if I remember correctly, to 43%. I didn't change it.
The A7 had RCA Low, bypass enabled.
The Yamaha AX 892 had CD Direct enabled (bypassing the selector and tone control). But I could adjust the volume.

I played a test track on the A7 and measured the volume using the Spectroid app installed on my smartphone. Then I played the same track on the AX 892 and adjusted the volume control to the same level, with an accuracy of 0.5 dB. The smartphone was placed in front of the speakers and didn't move.
I understand that this method isn't very accurate.

When I heard the difference in high-frequency reproduction, I even gave the A7 the edge during one of the repeats by slightly lowering the volume on the AX 892.
The high-frequency signature is the same—the A7's cymbal sound is shorter. It doesn't have the same richness as the Yamaha. At the same time, the sound is quite detailed. Subjectively, the highs are duller.
This is clearly audible when the sound of metal cymbals is emphasized in silence.
In the music I listen to (punk rock, trash, southern rock, alternative), I could no longer hear the difference.

 

[antcollinet]

This is clearly audible when the sound of metal cymbals is emphasized in silence.

If you are listening sighted you have no idea if it is clearly audible - or if your perceptive biases are causing the difference you perceive - which can sound very real and very distinctive.

 

[Argentum 05]

If you are listening sighted you have no idea if it is clearly audible - or if your perceptive biases are causing the difference you perceive - which can sound very real and very distinctive.

Yes, I understand psychoacoustics and realize I may be biased when listening. That's why I chose very short (15-20 seconds) sections of the test track for comparison. Unlike the low and mid frequencies, the difference in high frequencies was clearly audible. Furthermore, the cymbals were played in silence, without the distraction of other musical instruments.
I'm a proponent of the scientific approach, so I'm asking about the personal impressions of other participants on this forum.

Assuming the A7 mono is working properly and its parameters match Amir's measurements, then perhaps what I'm hearing is high-frequency distortion from the Yamaha, which I like?

I'd be interested in the experiences of other participants with AB amplifiers.

In any case, I'm currently biamping the A7 to boost the low frequencies.
And the old Yamaha works with the midrange/high frequencies.

 

[RandomEar]

Yes, I understand psychoacoustics and realize I may be biased when listening. That's why I chose very short (15-20 seconds) sections of the test track for comparison. Unlike the low and mid frequencies, the difference in high frequencies was clearly audible.

Again: Bias -> You having the impression that something is "clearly audible" does not mean that the difference actually exists. You made a good effort to do reasonably controlled testing, but you're still using long switching times, not quite good enough level matching and sighted listening.

Furthermore, the cymbals were played in silence, without the distraction of other musical instruments.
I'm a proponent of the scientific approach, so I'm asking about the personal impressions of other participants on this forum.

Assuming the A7 mono is working properly and its parameters match Amir's measurements, then perhaps what I'm hearing is high-frequency distortion from the Yamaha, which I like?

Unless your specific unit is broken, this is very unlikely. Specs list a THD of -82 dB for the Yamaha and that company really knows how to build decent class A/B amplifiers. The amp also does not know how long to play the cymbal sound - the length of the sound is part of the recording.

 

[antcollinet]

hat's why I chose very short (15-20 seconds) sections of the test track for comparison. Unlike the low and mid frequencies, the difference in high frequencies was clearly audible

If you are listening sighted you have no idea if it is clearly audible - or if your perceptive biases are causing the difference you perceive - which can sound very real and very distinctive.

It doesn't matter how many times you state it is clearly audible. The reliability of that observation does not improve.

I'm a proponent of the scientific approach,

Great.

so I'm asking about the personal impressions of other participants on this forum.

But that is not it.

 

[Argentum 05]

It doesn't matter how many times you state it is clearly audible. The reliability of that observation does not improve.

Sorry. In repeating my argument, I apparently didn't express my thoughts clearly enough. Or Google Translate obscured the semantic emphasis.
I know that the short auditory memory of Homo sapiens doesn't allow for such comparisons from memory.

Furthermore, subjective impressions may not correspond to reality.
I myself said this to a friend of mine who hears the voices of angels from expensive RCA cables.

Unfortunately, I don't have access to a measuring system like Amir's, so I emphasized that I essentially dissected a test music track, isolating short fragments with sounds characteristic of a specific frequency range. In this way, I tried to simplify the task as much as possible for my auditory memory. (It's a shame the Engineer didn't provide an upgrade

I can't distrust my hearing and critical thinking so much as to ignore the difference I heard in the high frequency range.

However, I understand your arguments and partially agree with them.

 

[Mort]

I can't distrust my hearing and critical thinking so much as to ignore the difference I heard in the high frequency range.

However, I understand your arguments and partially agree with them.

It's all about ego deflation at this point.

 

[RandomEar]

Sorry. In repeating my argument, I apparently didn't express my thoughts clearly enough. Or Google Translate obscured the semantic emphasis.

The translation is fine and perfectly coherent. But you can try DeepL and see if you like it better.

I know that the short auditory memory of Homo sapiens doesn't allow for such comparisons from memory.

Furthermore, subjective impressions may not correspond to reality.
I myself said this to a friend of mine who hears the voices of angels from expensive RCA cables.

Unfortunately, I don't have access to a measuring system like Amir's, so I emphasized that I essentially dissected a test music track, isolating short fragments with sounds characteristic of a specific frequency range. In this way, I tried to simplify the task as much as possible for my auditory memory. (It's a shame the Engineer didn't provide an upgrade

We would all like the upgrade The idea to use short and defined sections of the track to test is good. The main problem is that echoic memory is short not only in the sense that it can't store long sections of sound, but it's can't store anything at all for a "long" time: You'll loose details from memory after about 3-5 seconds. That's why any reliable comparison requires effectively instant A/B switching.

I can't distrust my hearing and critical thinking so much as to ignore the difference I heard in the high frequency range.

However, I understand your arguments and partially agree with them.

You don't need to distrust critical thinking. But in this case, you should think even more critically about trusting your hearing

It's not totally impossible that some difference exists: One amp may be out of spec, or there may be some overlooked switch or setting. But in general, it's unlikely that there are audible differences between well designed modern amps (apart from noise/tweeter hiss).

 

[Argentum 05]

The translation is fine and perfectly coherent. But you can try DeepL and see if you like it better.

Thanks, I'll try it sometime.

It's not totally impossible that some difference exists: One amp may be out of spec, or there may be some overlooked switch or setting. But in general, it's unlikely that there are audible differences between well designed modern amps (apart from noise/tweeter hiss).

I also suspect that this could be the cause.
I don't think the A7 could be faulty. Especially since I have an A7 mono, and they sound identical.
Yamaha 892 has been around for over a quarter of a century. Although, a couple of years ago, I took my Yama to an old-school repairman, who performed a full checkup and measured the values of some capacitors. According to him, the deviations were no more than 10% and nothing needed replacing. The contacts were cleaned of oxide.

I looked at Amir's tests today. Unfortunately, I couldn't find detailed tests of my Yamaha AX 892, but there are tests of the related AS 701 model. As far as I know, their designs are very similar. The 701 is even somewhat simplified compared to the 892. It's safe to assume that the 892's tests would be close to those of the 701.
There's also a test of the A7.
I was intrigued by one graph. Could it be that this difference is audible? After all, the sound of metal cymbals extends up to 15-20 kHz.

 

[RandomEar]

[...]
I also suspect that this could be the cause.
I don't think the A7 could be faulty. Especially since I have an A7 mono, and they sound identical.
Yamaha 892 has been around for over a quarter of a century. Although, a couple of years ago, I took my Yama to an old-school repairman, who performed a full checkup and measured the values of some capacitors. According to him, the deviations were no more than 10% and nothing needed replacing. The contacts were cleaned of oxide.

Sounds reasonable. It's an older amp, but it doesn't have to be bad/defective.

I looked at Amir's tests today. Unfortunately, I couldn't find detailed tests of my Yamaha AX 892, but there are tests of the related AS 701 model. As far as I know, their designs are very similar. The 701 is even somewhat simplified compared to the 892. It's safe to assume that the 892's tests would be close to those of the 701.
There's also a test of the A7.
I was intrigued by one graph. Could it be that this difference is audible? After all, the sound of metal cymbals extends up to 15-20 kHz.

This looks "uglier" at first glance, but the first distortion spike of this test (19 + 20 kHz dual tone) is at 18 kHz. You'll typically loose hearing in that region in your 30s, and before that, sounds need to be very loud to be audible at that frequency due to the equal loudness contuour. Apart from that, people typically fail to hear distortion below about -40 dB with real music in favorable listening tests, with some people in ideal scenarios reaching a bit below -50 dB with pure tones (not music). So even if you can still hear 18/19 kHz tones, you will not perceive distortion at -80 dB like in the test you linked