3e audio A7/A7 Mono Amplifier Review

[Matt1974]

"Hotter" is a very subjective term that can mean 32°C or 60°C.
The ambient temperature also plays an important role. At an ambient temperature of 20°C, 45°C would be quite high. However, at an ambient temperature of 38°C in summer, 45°C would be a good value.

Without a real measured value, no conclusions can be drawn. Reliable thermometers start at around €2, and infrared thermometers cost around €6-20.

‘Hotter than’ is not a subjective term. In fact humans with normal sensory functioning can detect differences of between 0.1 and 0.2 Celsius.

 

[Roland68]

‘Hotter than’ is not a subjective term. In fact humans with normal sensory functioning can detect differences of between 0.1 and 0.2 Celsius.

Humans are incapable of estimating absolute temperatures and are often off by 5-10 degrees.
Your objection only applies to absolutely identical materials and absolutely identical surfaces.
Even the difference in the roughness of a surface leads to miscalculations of several degrees. For different materials, the deviation in the estimate is already well over 10 degrees, often much higher.
Just as an example, if you take an object made of rough PLA out of an oven at 80°C with your hand, nothing will happen to you; it will just be very warm.
But if you take a piece of aluminum out of the oven at 50°C with your hand, you will burn your fingers.

 

[SMen]

I have the V3's and really like them a lot. Would appreciate it if you can elaborate on how the A7 outperforms the V3's.

I liked the V3 monos, but my processor only has unbalanced/rca outputs and the V3 monos don't sound nearly as good through the rca inputs. The E3 amp is much warmer/ fuller sounding than the Fosi through both inputs. The Fosi are thinner and sound more harsh/digital. Also, the e3 frees up a plug on my power conditioner. For my home theater, I had 4 V3 monos and 4 ZA3s which is 8 plugs! For $300 US, the e3 is a no-brainer upgrade over the V3 monos!

This is where @saberger0357 you need to just really like your V3 monos! Be happy! Or fork out for another 3255 variant (or 3251 it occurs to me) - I have just bought a second e3 so I have both the 3251 and the 3255 (3e A5 & A7) .... and the V3 monos ... so time for a clear out... after I have tried the A7's.


If the 3e 7 is much fuller and warmer sounding then it may not sound like the A5 ... which sounds more transparent to source to me than the V3 Monos! If anything the Monos sound fuller and more rounded ... perhaps it is a source thing... but if anything the V3 Monos have more of a sound signature.

Anyway - I will try the A7. I'm going to keep them so long as they work ... I travel a bit so they will be put to good use ... maybe put it down to simply educational!

 

[Pulkass]

• Received my A7 stereo today from US Amazon. I can confirm it outperforms the Fosi V3 monos in my setup. However, it runs hotter than I would like. At idle, the top hits 108 degrees Fahrenheit vs 116 for the Fosi monoblocks. I'm a little disappointed, as I was hoping not to have to use cooling fans with it. However, it sounds better than the Fosi and the rca inputs sound just as good as the xlr. I had planned to get another, but it's no longer listed on Amazon, just the mono version. Can 3e clarify why the stereo version has disappeared from Amazon US?

Is it worth changing the two Opas with two 627s . Have we some sonic improvement?

 

[Roland68]

Is it worth changing the two Opas with two 627s . Have we some sonic improvement?

Basically, no. Please read Amir's tests and reports on replacing op amps.

It also never makes sense to replace an op amp without adjusting the circuitry. Do you do that?
The 627 is a unity gain op amp, so it could be completely mismatched at that point.
Genuine 627s currently cost at least €20 each; everything else is fake and costs a few cents. Since it's a single op amp, you'll need 4-6 of them, depending on the input.

 

[Panelhead]

The OPA1612 is no slouch. Has replaced the LM4562 in many new high performance products.
The noise and THD+N are so low getting better is a trade off. 0.000012% is below the analyzer resolution.

 

[saberger0357]

This is where @saberger0357 you need to just really like your V3 monos! Be happy! Or fork out for another 3255 variant (or 3251 it occurs to me) - I have just bought a second e3 so I have both the 3251 and the 3255 (3e A5 & A7) .... and the V3 monos ... so time for a clear out... after I have tried the A7's.

I do really like the V3's. But my inquiry was to better understand @avdoc 's comment that the A7 "outperforms" the V3's. If the comment is meant to say that to his ears it sounds better, that's fine. One's preference for one type of sound over another is reasonable, although I still would be interested in what it is about that sound that he likes better. And of course we've all seen the review measurement so that we know on paper at least the A7 does indeed outperform the V3's.

Just trying to get some clarification.

 

[SMen]

I do really like the V3's. But my inquiry was to better understand @avdoc 's comment that the A7 "outperforms" the V3's. If the comment is meant to say that to his ears it sounds better, that's fine. One's preference for one type of sound over another is reasonable, although I still would be interested in what it is about that sound that he likes better. And of course we've all seen the review measurement so that we know on paper at least the A7 does indeed outperform the V3's.

Just trying to get some clarification.

3e A5 ... more transparent to source to my ears ... you are absolutely right to ask for clarification from @avdoc

Going to try the A7s shortly. The V3 Monos 'sound' great too.

 

[ziggurcat]

@Roland68 so after one of the last bits of discussion, you mentioned a trying a USB isolator -- I have a Topping HS02 arriving tomorrow, and can finally give it a try. I'm sure it's more than what I should have paid, but it's an Amazon order. If it turns out to not resolve anything, it can be returned, so there's virtually no risk. If it does the trick, then I can put the A7 in its intended home, and enjoy!

Will follow up once I've had a chance to try it out.

 

[ziggurcat]

@Roland68

First, apologies for making a new post in the thread, the ability to edit the post above literally just disappeared when I went back in the thread history to verify some information.

The isolator did not resolve the problem. One thing that I did notice is that with the D50 III in preamp mode (volume was -38.5dB), and the A7 volume bypass disabled, the popping was louder than when I set the D50 III to DAC mode/A7 with volume bypass disabled (TRS cables from DAC to amp). This was probably the case before, but I never thought to make note. The only weird thing was the popping ended up only in the right channel (it also wasn't audible 2ft away). My recollection is it was in both channels previously under the DAC mode/volume bypass disabled condition (TRS cables from DAC to amp).

This is interesting to me because last time when I thought I had figured out a way to use the amp with my Mac, under the conditions of the D50 III being in preamp mode/A7 volume bypass enabled, the popping was only in the left channel, and not audible from 2ft away. I did not try preamp mode/bypass enabled with the isolator because I figured if it didn't really resolve it under any other condition, it probably isn't going to resolve it in that scenario, either.

Anyways, no need to respond or anything, I am just following up as promised. The TL;DR is I'll be sending the isolator back tomorrow.

 

[Bryguy]

@3eaudio will the Stereo A7 with internal PSU be released this year? I bought V3 Mono's used on Facebook marketplace to hold me over until the release of this device. Wondering what the timeline looks like? Also wondering if this device will have 12v trigger? Really been annoyed by the standby in the V3 mono's, and not being able to select how long it idles before shutting off. I am interested in the A7 because of its improved RCA performance over the V3 Mono's, and I don't like the clutter of monoblocks and external PSU's.

 

[sebanow]

Got my A7 a couple days ago, and here are my initial impressions for anyone interested.
Amp is roughly twice the size and weight of Douk A5/Fosi V3. There is a lot of vents on the sides and at the bottom of the enclosure. Thanks to Amirm we know that op-amp rolling makes little to no sense, but here we can swap them easily, since there are two holes in the bottom plate, allowing for easy access to op-amps. However, space is limited, so any big, discrete op-amp may not fit.
Initial impression, using RCA, on both high and low gain, was a little perplexing, since, when compared to two above mentioned amps, the amount of bass squeezed from my old Diamonds 10.7 was huge! For all amps I've used the same power supply, 48/10, but the resulting drive is really different with these speakers. I've never heard them produce powerful low end to such an extent. So much that I was initially suspecting some sort of correction is applied by the amp But after more listening, testing different genres, I'm sure this is not the case here
When using XLR the effect is more subdued, at least to my layman's ears. But maybe that's because of the general lower sound level that I'm using. For the RCA turning the volume knob to, say, 9-10 o'clock resulted in a high volume sound as for my usual listening. Now I'm using XLRs with volume bypass, and DAC used as a preamp.
There are no clicks, at least those heard through the speakers, also the power up is perfectly silent. The only thing you can hear are amp internal relays clicking when it auto powers on or while switching inputs.
I'm very happy with my purchase, and both my A5 and V3 will be looking for new owners soon.
My setup is Wiim Mini, toslinked to S.M.S.L D-6s, connected via XLR to 3e audio A7 with 48V/10A power supply, and Wharfedale Diamond 10.7 speakers.
In total I've paid 192 euros for the amp with 48V/5A power supply at AliExpress summer sale with some kind of price adjustment for VAT tax. Price includes border tariff of around 5%, however the VAT was not collected at all by customs (?).

 

[anonyless]

but here we can swap them easily, since there are two holes in the bottom plate, allowing for easy access to op-amps. However, space is limited, so any big, discrete op-amp may not fit.

actually the 2 big holes are for allowing big op-amps to stick out of the case. in that scenario, you can use the A7/5 upside down (saw someone on YT (or here?) that did just that

 

[sebanow]

actually the 2 big holes are for allowing big op-amps to stick out of the case. in that scenario, you can use the A7/5 upside down (saw someone on YT (or here?) that did just that

You can also use the case as a cheese grater Holes are 18x18 millimeters, and there's not too much depth as you pointed out. So Burtons should fit (probably sticking out, maybe raisers will be better than upside down position for the whole amp?), but Sparkos, Staccatos will not, that's all. Most of the op-amps will surely fit with no issue at all.

 

[ziggurcat]

@Roland68 I have a question for you:

So today, I thought I would test the A7 amp out again, this time using a completely different computer. My inital tests were done with a Mac Mini, the other computer I have is a Macbook Air M2 laptop. Using my E50 DAC, it was connected via USB to the Air, TRS out from the DAC to the A7. I got the same popping issue when pausing/stopping any audio.

I didn't go too extensive in the testing this time, but I did try each device in their main configurations (i.e. E50's DAC/preamp modes, and A7's volume bypass on/off). It was not as loud when the E50 was in preamp mode (volume -30dB) and the A7's volume bypass enabled. With the E50 in DAC mode/A7 bypass disabled, volume knob was at about the 9 o'clock position on the A7. And it was only one pop instead of two. I also only used one speaker, and it was connected to the Left channel on the amp.

What would your assessment be on this because I am now finding it pretty difficult to believe that both of my computers are the problem. I understand that it is a complicated issue, but I thought I had it figured out. I would also put out the same question to anyone else here, including @3eaudio

 

[Roland68]

@Roland68 I have a question for you:

So today, I thought I would test the A7 amp out again, this time using a completely different computer. My inital tests were done with a Mac Mini, the other computer I have is a Macbook Air M2 laptop. Using my E50 DAC, it was connected via USB to the Air, TRS out from the DAC to the A7. I got the same popping issue when pausing/stopping any audio.

I didn't go too extensive in the testing this time, but I did try each device in their main configurations (i.e. E50's DAC/preamp modes, and A7's volume bypass on/off). It was not as loud when the E50 was in preamp mode (volume -30dB) and the A7's volume bypass enabled. With the E50 in DAC mode/A7 bypass disabled, volume knob was at about the 9 o'clock position on the A7. And it was only one pop instead of two. I also only used one speaker, and it was connected to the Left channel on the amp.

What would your assessment be on this because I am now finding it pretty difficult to believe that both of my computers are the problem. I understand that it is a complicated issue, but I thought I had it figured out. I would also put out the same question to anyone else here, including @3eaudio

At this point, it would be interesting and useful if someone could use an oscilloscope to measure whether and when these noises are present in the signal.

It would be interesting to test this with a Windows system. Perhaps you could borrow a Windows laptop from someone.

Did you run the test on a MacBook with and without the power adapter?

 

[ziggurcat]

At this point, it would be interesting and useful if someone could use an oscilloscope to measure whether and when these noises are present in the signal.

It would be interesting to test this with a Windows system. Perhaps you could borrow a Windows laptop from someone.

Did you run the test on a MacBook with and without the power adapter?

I have no way to test that, personally.

I would love to be able to test it out on separate Windows system. I can ask around if anyone is willing to lend me a laptop for a brief period of time.

With the D50 III, I did test with and without the additional USB power connected. The E50 DAC I have (which is what I used to test with the laptop today), I think, requires the power cable to be connected, but I honestly haven't tested that DAC with just the USB connected to my computers.

Now... I think this is where it gives you a clearer idea of where the issue actually lies (and back to what you told me initially)... I did finally observe the issue with my PA5 II amp despite not noticing anything for over a year with this amp. The whole thing was completely missed because of how I have had it set up (D50 III in DAC mode, using PA5 II to control volume).

With the D50 III in preamp mode (volume -45dB and above), and the PA5 II volume knob turn to its max, faint popping was observed only in the Left channel (absolutely nothing in the Right channel) when my ear was within a few inches of the drivers (not audible from 2ft away). Zero popping in that same configuration listening with headphones. Zero popping in either channel (made sure to hold my ears very close to the speaker drivers) when D50 III DAC mode is enabled/PA5 II volume at about the 9 o'clock position (which is not the case with the A7).

So either this is a general Mac issue (which is why I think it's important to try a Windows laptop) or the electrical in my condo is the problem (best thing I can for that is connect a Mac and Windows laptop to my Flex via USB in my HT, and see if I can hear any popping in either channel).

So sorry, I recognize how much of a dumb, wild goose chase this whole thing is. I recognize how inconsistent things have been, but it's only because new information surfaces, which does cause some contradictions (I assure you I have been completely forthright and honest in the information I have presented). I fully accept a swift smack upside the head from everyone here.

 

[RedCannon]

Im 99% positive it will be your Pc. My girlfirends windows 11 desktop will make the powered kef speakers go pop if the wiim is already on. I have the A7 hooked up to my denon to tv. No pops except the only device that will make it go pop is my nintendo switch 2(switch 1 doesnt do this ), unless the a7 is off before i turn everything on. The switch 2 will make anything i connect to pop.
Im assuming pcs will make a popping sound intentionally to turn on the device that has auto power on feature(or just an unintentional design feature that computer manufacturers could care less about audio). If you still want assurance I could test the A7 on a windows laptop tomorrow if you want.

 

[ziggurcat]

Im 99% positive it will be your Pc. My girlfirends windows 11 desktop will make the powered kef speakers go pop if the wiim is already on. I have the A7 hooked up to my denon to tv. No pops except the only device that will make it go pop is my nintendo switch 2(switch 1 doesnt do this ), unless the a7 is off before i turn everything on. The switch 2 will make anything i connect to pop.
Im assuming pcs will make a popping sound intentionally to turn on the device that has auto power on feature(or just an unintentional design feature that computer manufacturers could care less about audio). If you still want assurance I could test the A7 on a windows laptop tomorrow if you want.

Because I have now observed it with my PA5 II amp, I think I can say that the A7 is absolved. Check if you want, but I am almost certain it won't happen on your end. If you do, I would invite you to send a PM instead with any follow-up.

After some more testing, I can now also say that I heard it with headphones despite not hearing it earlier today. It was missed because of the gain setting on my L50 HPA. Zero pops with my L50 set to Low gain (D50 in preamp mode, volume as high as -10dB), but pops in the Left channel when the gain switch on the L50 is on Medium or High (D50 in preamp mode, volume set as low as -70dB in either of those gain settings).

And as with the previous testing with the A7 from about a month or so ago, if I set the input on the DAC to Bluetooth, and stream from the Mac that way, no popping occurs at all in any D50 III/PA5 II configuration.

Anyway, I feel all of this is now really off-topic (I mean, the issue probably has been for a little while, I just came across some curious results today), so I'll leave it at that, and move on, and try not to bother anyone anymore about this (I can almost feel the eye rolls every time I add any new information).

 

[Roland68]

Because I have now observed it with my PA5 II amp, I think I can say that the A7 is absolved. Check if you want, but I am almost certain it won't happen on your end. If you do, I would invite you to send a PM instead with any follow-up.

After some more testing, I can now also say that I heard it with headphones despite not hearing it earlier today. It was missed because of the gain setting on my L50 HPA. Zero pops with my L50 set to Low gain (D50 in preamp mode, volume as high as -10dB), but pops in the Left channel when the gain switch on the L50 is on Medium or High (D50 in preamp mode, volume set as low as -70dB in either of those gain settings).

And as with the previous testing with the A7 from about a month or so ago, if I set the input on the DAC to Bluetooth, and stream from the Mac that way, no popping occurs at all in any D50 III/PA5 II configuration.

Anyway, I feel all of this is now really off-topic (I mean, the issue probably has been for a little while, I just came across some curious results today), so I'll leave it at that, and move on, and try not to bother anyone anymore about this (I can almost feel the eye rolls every time I add any new information).

Actually, not from me, but I specialize in narrowing down and analyzing problems.
Without measurements, such a thing is of course only possible to a limited extent.
But you're not alone, because such problems arise again and again and are often difficult to solve.

I would actually assume that the noise is being generated in the computer, possibly in the USB output area.
There might be an easy way to narrow it down.
With an SMSL PO100 or PO100 Pro and a Toslink connection to the DAC, you should be able to rule out everything else. This galvanic isolation then only transmits the actually present signal components.

If there is an eye roll, it is more likely due to helplessness in the face of such problems.