3e audio A7/A7 Mono Amplifier Review

[SMen]

I said the ZA3 plays louder, I didn't say I preferred it because it played louder. I prefer it because I find it sharper in the mid and high range and that is a nice fit with my speaker, and I find the A7 is more rolled-off, more layback, with a less pronounced soundstage.

The a7 has more body and thats what the za3 is missing. The hype on YouTube is just as big for the A7 as it is for the ZA3.

You guys make me laugh when you say there's no perceptible difference without even having heard it, when there's a clear and obvious difference here in my living room. Of course after a glass of wine or if im tired or whatever i would maybe prefer the A7, because exatcly maybe im tired of hearing the za3 and vice versa because the sound is different and they both dont sound the same at all.

I am not sure what speakers you are using but what you are describing seems to me to be the difference between PFFB vs non PFFB designs. There is likely to be more variation between different speakers when using a non PFFB amp (the ZA3). I suspect the damping factor is better with the A7 amongst other things. Volume controls (never mind matching levels) are taken out of the equation when measurements are taken too ....

The fact that you prefer the ZA3 might well be because it isn't as "good" as the A7 - which might well be your point - but "sharper in the high range" might be because the ZA3 is non-PFFB with speakers that react to this ... and long term this might wear off as being preferable ... so going with the better measuring amp might be better long term.

But if no-one can hear any difference between PFFB and non-PFFB implementations, then there is no point in the latter!

Post edit ... just seen you last post.

 

[john61ct]

So I finally order both fosi za3 and e3 A7 yesterday and did some good listening session.

One thing for sure the za3 plays definitly louder… to hit 90dB with A7 i had to put preamp at 90% volume while za3 preamp volume was at 70% for same dB

To me that scaling issue is irrelevant to actual SPL output capacity.

Which, assuming maximum output does not hit clipping or damage the speakers involved

is easily measured with objective equipment. And likely both units have been, here

 

[harkpabst]

I’m in XLR with gain 100% and my preamp at ~90% to hit 95 dB

I was referring to the fact that the 3E AUDIO A7 has a switchable gain of 26 dB or 29 dB (see the switch on it's connection panel), but this is for the RCA inputs, only. The XLR input has a fixed gain of 20 dB. If your (unknown to us) pre-amp has a balanced output, it should usually provide a maximum output voltage of 4 V (newer designs often support 5 V). Using the A7 XLR inputs the input sensitivity is 3.5 V. That means, as long as the pre-amp can output at least 3.5 V (with the volume know at 100% and with sources matching the pre-amps input sensitivity), you will get the full output power of 208 W into 4 ohm or 114 W into 8 ohm (following Armir's standards).

Do you know the max output voltage of your pre-amp?

 

[Pat La Sauce]

I was referring to the fact that the 3E AUDIO A7 has a switchable gain of 26 dB or 29 dB (see the switch on it's connection panel), but this is for the RCA inputs, only. The XLR input has a fixed gain of 20 dB. If your (unknown to us) pre-amp has a balanced output, it should usually provide a maximum output voltage of 4 V (newer designs often support 5 V). Using the A7 XLR inputs the input sensitivity is 3.5 V. That means, as long as the pre-amp can output at least 3.5 V (with the volume know at 100% and with sources matching the pre-amps input sensitivity), you will get the full output power of 208 W into 4 ohm or 114 W into 8 ohm (following Armir's standards).

Do you know the max output voltage of your pre-amp?

I’m using fosi ZD3 dac (not preamp sorry) for the moment, but planning on switching to fiio k13. And I stream my music from WIIM mini.

 

[GGroch]

I’m using fosi ZD3 dac (not preamp sorry)

So 5Vrms on the Balanced and 2.5Vrms on the RCA outputs. Either output will easily drive the A7 to its maximum levels, even if you use the lower 26dB sensitivity.

More consumer-oriented brands frequently use higher gain on their inputs as it makes the amp seem more powerful because you get higher output with less rotation of the volume knob.

More audiophile-oriented companies frequently use lower gain to allow you to make finer adjustments (utilizing a larger part of the volume knob rotation). In this case, your DAC should match both of your amp choices just fine. But, you have to crank the volume of the A7 up higher when using RCA inputs. They did that on purpose, but your preference is your preference.

 

[RandomEar]

I said the ZA3 plays louder, I didn't say I preferred it because it played louder. I prefer it because I find it sharper in the mid and high range and that is a nice fit with my speaker, and I find the A7 is more rolled-off, more layback, with a less pronounced soundstage.

No, we said you likely preferred it because you perhaps played it a little louder. And we explained why precise volume matching matters.

The a7 has more body and thats what the za3 is missing. The hype on YouTube is just as big for the A7 as it is for the ZA3.

The hype in YouTube is big for many of these cheap new amps. Reviewers will always say how they sound so special in X and possess awesome Y, because they rely on positive reviews to keep getting send devices for free. If they were overly critical or even just honest, companies are likely to cut them off. The reviewers wouldn't like that because often, their livelihood depends on their channels making enough money. You don't make (much) money if you don't review the newest and most popular shit.

You guys make me laugh when you say there's no perceptible difference without even having heard it, when there's a clear and obvious difference here in my living room. Of course after a glass of wine or if im tired or whatever i would maybe prefer the A7, because exatcly maybe im tired of hearing the za3 and vice versa because the sound is different and they both dont sound the same at all.

We have explained multiple times and in detail that thinking or perceiving a difference in sighted testing is expected and does not mean at all that such a difference exists. This statement is true regardless of who listened to which devices when and where.

In case of the ZA3 vs A7, such an audible difference might actually exist with your speakers due to the pronounced load dependency of the ZA3. However, the uncontrolled route you took for testing is as valid in finding those potential differences as no testing at all.

The next person who posts their subjective impressions of these two amps is a coin flip away from stating the opposite of your impression. That's the problem with subjective testing: The results are mostly just noise and add nothing to a science-focused forum.

 

[SMen]

No, we said you likely preferred it because you perhaps played it a little louder. And we explained why precise volume matching matters.


The hype in YouTube is big for many of these cheap new amps. Reviewers will always say how they sound so special in X and possess awesome Y, because they rely on positive reviews to keep getting send devices for free. If they were overly critical or even just honest, companies are likely to cut them off. The reviewers wouldn't like that because often, their livelihood depends on their channels making enough money. You don't make (much) money if you don't review the newest and most popular shit.


We have explained multiple times and in detail that thinking or perceiving a difference in sighted testing is expected and does not mean at all that such a difference exists. This statement is true regardless of who listened to which devices when and where.

In case of the ZA3 vs A7, such an audible difference might actually exist with your speakers due to the pronounced load dependency of the ZA3. However, the uncontrolled route you took for testing is as valid in finding those potential differences as no testing at all.

The next person who posts their subjective impressions of these two amps is a coin flip away from stating the opposite of your impression. That's the problem with subjective testing: The results are mostly just noise and add nothing to a science-focused forum.

although I do like it when users post 'no subjective differences' when comparing the A7 to something twice or three times the price .

The load dependency of the ZA3 accentuates the issue (unpredictable perceived differences).

 

[delta76]

No, we said you likely preferred it because you perhaps played it a little louder. And we explained why precise volume matching matters.


The hype in YouTube is big for many of these cheap new amps. Reviewers will always say how they sound so special in X and possess awesome Y, because they rely on positive reviews to keep getting send devices for free. If they were overly critical or even just honest, companies are likely to cut them off. The reviewers wouldn't like that because often, their livelihood depends on their channels making enough money. You don't make (much) money if you don't review the newest and most popular shit.

that is true, and just to add, the youtubers (or influencers in general) rely on bipolar opinions to attract viewers. So either a new great cheap product (X killer for half/third the price), or a very harsh review. Smaller youtubers usually lean toward the former, while established youtubers will lean toward the latter (more time and effort needed, and manufacturers will not easily retaliate you for a bad review)

Fosi ZA3 is cheaper so yes they will get glowing reviews compared to more expensive amps, because that is what excite viewers.

balanced, measurement backed reviews will not get the views.

 

[peng]

You're right, we don't know for sure. Yet, it's the perfect first step. It's free and - given that most all volume pots are logarithmic (for a good reason) - chances are that the last 10 % make a bigger difference than each of the previous 10 % steps.

Also, @Pat La Sauce still didn't tell us about the gain setting and/or the input used on 3E AUDIO A7.

That's true, and only take a second to find out if turning it all the way to max gets him louder than he can tolerate lol.

 

[peng]

I am not sure what speakers you are using but what you are describing seems to me to be the difference between PFFB vs non PFFB designs. There is likely to be more variation between different speakers when using a non PFFB amp (the ZA3). I suspect the damping factor is better with the A7 amongst other things. Volume controls (never mind matching levels) are taken out of the equation when measurements are taken too ....

The fact that you prefer the ZA3 might well be because it isn't as "good" as the A7 - which might well be your point - but "sharper in the high range" might be because the ZA3 is non-PFFB with speakers that react to this ... and long term this might wear off as being preferable ... so going with the better measuring amp might be better long term.

But if no-one can hear any difference between PFFB and non-PFFB implementations, then there is no point in the latter!

Post edit ... just seen you last post.

That's possible, but practically speaking, I doubt the difference would be audible to most people, of the more than 10 metrics Amir typically measured, the one below is one that is a reliable indicator:

This graph shows in the 20-20000 Hz (assuming the op cannot hear the 2nd and higher harmonics of 10 kHz, and the IMD due to the ultrasonic frequencies are high enough to be audible neither), between at 0.05 W to over 100 W into 4 ohms and likely better into 8 ohms, distortions plus noise would be at below -55 dB or <0.2 %.

So, PBFB or not is not likely going to make the " a clear and obvious difference" the op thought he was hearing, unless it wasn't truly an apple to apple comparison.

 

[peng]

You guys make me laugh when you say there's no perceptible difference without even having heard it, when there's a clear and obvious difference here in my living room. Of course after a glass of wine or if im tired or whatever i would maybe prefer the A7, because exatcly maybe im tired of hearing the za3 and vice versa because the sound is different and they both dont sound the same at all.

I wonder if you have read what Dr. Floyd Toole's articles on blind listening tests and if you did, keep in mind he's talking about loudspeakers, but the same would apply (much more so) to comparing power amplifiers that are infinitely more similar than different in real world "sound quality" performance.

There are plenty of posts on ASR about the need to do listening test blind, below is quote from one of the many articles written by Dr. Sean Olive:

https://seanolive.blogspot.com/2009/04/dishonesty-of-sighted-audio-product.html:

if you want to obtain an accurate and reliable measure of how the audio product truly sounds, the listening test must be done blind.

He's also talking about loudspeakers though, but again if we need to do it blind for loudspeakers, we obviously need to do it with amplifiers.

It is good that some of us made you laugh, after all, this is just a hobby so don't need to get mad or upset about something we don't agree on partially or even entirely. No one knows what you heard, all some of us might just be suggesting that there are other factors, such as how one does such comparison listening to ensure the tests will be done on as truly apples to apples as possible basis.

Obviously we all agree we don't listen to measurements, but measurements, if done well enough, could, or should provide reliable information that allow us to predict how well the dut would perform when listening to real world contents. Amplifiers designers rely mostly on measurements to verify/validate their design/implementation/builds based on proven design and past success etc., typically not by ears. As an example, even the silly Marantz/Denon marketing hypes, merely claimed they used their so called sound masters to do the final listening test to guide their colleagues to do the final tuning, it's silly (in my opinion) but at least that's done in the final step, when any real tuning that might change the results would be minor and seemingly so trivial enough that the results did not seem to show up in independent (such as ASR, Audioholics.com, or their own internally done bench test measurements.

Sorry I am getting too lengthy on this, but if I understand correctly, you are planning on making your choice after listening to 3 amps, that's a lot of work, so I am trying to give you a slight push to doing some, or more read up on subjective comparison listening that are done sighted and often without stricter control on ensuring apples to apples comparison versus doing it "blind". If and when you get more convinced on specs and measurements (good ones such as those by ASR) are reliable enough, you will save yourself time, effort and money in the selection process.

For me, between the ZA3 and the A7, if aesthetic is more important to me than verified specs, ZA3 would have been my pick, but I am ocd on specs/measurements so I picked the A7, though would have been happy with the ZA3 also.

 

[harkpabst]

I’m using fosi ZD3 dac (not preamp sorry) for the moment, but planning on switching to fiio k13. And I stream my music from WIIM mini.

Thanks for clarification. The ZD3 perfectly qualifies as a pre-amp in my book.

How did you connect the WiiM Mini? I guess (and I hope) that you are using the optical connection (as analog RCA doesn't make any sense). Any chances you have set a "Volume Limit" in the Mini's "Audio Settings"? This could result in a too low input signal for the ZD3.

The ZD3 with its up to 5 Vrms XLR outputs can "safely" overdrive the input of the 3E AUDIO A7 with its 3.5 Vrms input sensitivity!

Either output will easily drive the A7 to its maximum levels, even if you use the lower 26dB sensitivity.

Remember: The sensitivity of the balanced input is fixed at 20 dB, the gain switch applies to RCA, only.

@Pat La Sauce, technically I see no benefit in the K13 R2R over the ZD3, rather the contrary. Of course, R2R DACs are heavily supported as as sounding more analog the delta-sigma DACs. Interestingly, when CDs came out all DACs were R2R and back then nobody thought that they sounded particularly analog. All the typical technical specs are better then for the (still excellent) K13 R2R.

If you're also after the headphone amp missing on the ZD3, that might be a different story.

This graph shows in the 20-20000 Hz (assuming the op cannot hear the 2nd and higher harmonics of 10 kHz, and the IMD due to the ultrasonic frequencies are high enough to be audible neither), between at 0.05 W to over 100 W into 4 ohms and likely better into 8 ohms, distortions plus noise would be at below -55 dB or <0.2 %.

So, PBFB or not is not likely going to make the " a clear and obvious difference" the op thought he was hearing, unless it wasn't truly an apple to apple comparison.

PFFB is not only about reducing distortion, but much more about reducing the output impedance.

A low output impedance over the entire audio frequency range is required for the amp to be not load dependent. Practical load dependency as observed with class-D chip amps without PFFB changes the measured frequency response of the speakers. Not just in the upper highs but - depending on the impedance response of the speaker - starting in the upper mods.

I won't overstate this, but our hearing is actually sensitive to loudness variation over frequency.

 

[peng]

Thanks for clarification. The ZD3 perfectly qualifies as a pre-amp in my book.

How did you connect the WiiM Mini? I guess (and I hope) that you are using the optical connection (as analog RCA doesn't make any sense). Any chances you have set a "Volume Limit" in the Mini's "Audio Settings"? This could result in a too low input signal for the ZD3.

The ZD3 with its up to 5 Vrms XLR outputs can "safely" overdrive the input of the 3E AUDIO A7 with its 3.5 Vrms input sensitivity!


Remember: The sensitivity of the balanced input is fixed at 20 dB, the gain switch applies to RCA, only.

@Pat La Sauce, technically I see no benefit in the K13 R2R over the ZD3, rather the contrary. Of course, R2R DACs are heavily supported as as sounding more analog the delta-sigma DACs. Interestingly, when CDs came out all DACs were R2R and back then nobody thought that they sounded particularly analog. All the typical technical specs are better then for the (still excellent) K13 R2R.

If you're also after the headphone amp missing on the ZD3, that might be a different story.


PFFB is not only about reducing distortion, but much more about reducing the output impedance.

A low output impedance over the entire audio frequency range is required for the amp to be not load dependent. Practical load dependency as observed with class-D chip amps without PFFB changes the measured frequency response of the speakers. Not just in the upper highs but - depending on the impedance response of the speaker - starting in the upper mods.

I won't overstate this, but our hearing is actually sensitive to loudness variation over frequency.

I did read up on PFFB before I purchased the A7, so thank you, and I was aware of the benefits of the PFFB thing. That's why I looked and compared the two amp's performance on the posted graphs, so as to see the measured effects. I believe I can sense loudness variation over frequency too, but the question is, how subtle, or obvious the effects would be, to me, I wouldn't doubt the OP heard some "difference", in whatever form, my skepticism would be on his "..clear and obvious difference....", though I should realize everyone's clear, obvious, may not mean the same.

 

[StephenMarkLay]

Would a mono A7 be able to run a 2 ohm sub without overheating?

 

[harkpabst]

Would a mono A7 be able to run a 2 ohm sub without overheating?

It's officially specified to output 480 W into 2 ohm at 1% THD-N and Amir's measurements pretty much confirm this.

A 10 A PSU is certainly advisable in this scenario.

 

[antcollinet]

You guys make me laugh when you say there's no perceptible difference without even having heard it, when there's a clear and obvious difference here in my living room.

What though if you knew that what you hear can be influenced by all sorts of things other than what is in the soundwaves reaching your ears, such as what you can see, what you are looking at. What you feel about what you are looking at, how you feel, how comfortable you are - and a million other things.


Your unconscious brain actually alters your perception of the sound in between your ears, and your conscious "hearing", and will make "clear and obvious differences" that don't exist in the sound waves. Also applies to all our other senses.

It is why blind testing is used in all areas of scientific investigation where human perception is being tested.

 

[harkpabst]

I did read up on PFFB before I purchased the A7, so thank you, and I was aware of the benefits of the PFFB thing. That's why I looked and compared the two amp's performance on the posted graphs, so as to see the measured effects. I believe I can sense loudness variation over frequency too, but the question is, how subtle, or obvious the effects would be, to me, I wouldn't doubt the OP heard some "difference", in whatever form, my skepticism would be on his "..clear and obvious difference....", though I should realize everyone's clear, obvious, may not mean the same.

I'm sorry if my tone came across as patronising, that surely wasn't my intention.

I still think we really don't know how much of an objective difference might be there in this scenario. It all depends on the speakers. More perceived top end could absolutely be perceived due to load dependency. We audiophiles (yes, I do call myself an audiophile) tend to happily jump on the slightest difference we were happy enough to recognize (at least we think we did) and exaggerate the results.

 

[GGroch]

I did read up on PFFB before I purchased the A7,

Ironically, it is much easier to "hear" the difference PFFB makes in listening tests after having read up up on it. As harkpabst points out, one can more clearly "hear" the benefits of R2R DACs if their theoretical benefits are known to you.

We scientific types are often immune to power cord and speaker cable bias** because their impact is not measurable and does not make technical sense. OTOH, we are probably more susceptible to the audibility of PFFB or R2R because we understand what they do. In my case, I am confident my A5 sounds better than my old TPA3255 amp because it measures slightly better and has PFFB, even though at 72 I cannot hear the frequencies PFFB impacts.

In the a real room using real speakers, the impact PFFB has on frequency response will be inaudible, or perhaps barely audible and compensated for by towing your speaker in or out very slightly. Please tell me if I am wrong on this.

**This is wrong, we are negatively biased. A probably apocryphal test years ago describes a room full of scientific audiophiles who were told they would be comparing the sound of a system swapping out standard and audiophile power cables. Unsurprisingly none of the listeners heard a difference. The story goes that what was actually being switched was speaker polarity, an easily audible change. The scientific types were blinded by their scientific bias to real audible differences.

 

[Roland68]

Would a mono A7 be able to run a 2 ohm sub without overheating?

That depends on the power you need. Without very precise data, no one can say for sure, but there are plenty of online calculators you can use to estimate your power requirements.

However, the A7's actual continuous power output per channel is 100-120 watts at 2 ohms and 135-160 watts at 4 ohms. The latter figure only applies with an additional large heatsink and good airflow.

Alternatively, you could use the SMSL A300 as a subwoofer amplifier. Bridged at 4 ohms, it delivers over 400 watts (measured by Amir in his test). It's only rated for 4 ohms, but at 400 watts, it's likely one of the most affordable Class D amplifiers with such high power output.
You can find it on sale for as little as €150-160.

It's officially specified to output 480 W into 2 ohm at 1% THD-N and Amir's measurements pretty much confirm this.

A 10 A PSU is certainly advisable in this scenario.

These are just the values from the datasheet for the maximum (short-term) possible power.
The power measured by Amir is also only a short-term value.

 

[StephenMarkLay]

That depends on the power you need. Without very precise data, no one can say for sure, but there are plenty of online calculators you can use to estimate your power requirements.

However, the A7's actual continuous power output per channel is 100-120 watts at 2 ohms and 135-160 watts at 4 ohms. The latter figure only applies with an additional large heatsink and good airflow.

Alternatively, you could use the SMSL A300 as a subwoofer amplifier. Bridged at 4 ohms, it delivers over 400 watts (measured by Amir in his test). It's only rated for 4 ohms, but at 400 watts, it's likely one of the most affordable Class D amplifiers with such high power output.
You can find it on sale for as little as €150-160.


These are just the values from the datasheet for the maximum (short-term) possible power.
The power measured by Amir is also only a short-term value.

Thank you! so there is a drop in power into 2ohms? I will check out the SMSL A300. Much appreciated!