3e audio A7/A7 Mono Amplifier Review

[harkpabst]

Wow, I did not think those two were equivalent?

It depends of the definition of "equivalent".

Amir did not even test both units separately, because the A7 Mono is really the same PCB as the A7 (stereo), but only the components for one channel are fitted. The A7 Mono accepts a slightly higher supply voltage, so it can crank out just a bit more power, since the case has to cool one channel, only. An A7 (stereo) can be used just the same when only one channel is used (which nobody would do for two channels because you would be paying for parts you don't use). So, from a technical point of view they are "equivalent".

Using a pair of A7 Mono amps with a dedicated 10 A PSU for each one is still different from using a single A7 (stereo) with one single PSU (maybe even 5 A). Again, if this is needed of not is a different question, but not one for a man on a mission.

While I've gotcha, did I get this right(ish)?

I'd say "mostly right". Down to 4 or 3.5 ohms there won't be a difference in power output between the WiiM Vibelink Amp and the WiiM Amp Ultra. the BTL config can provide all the current that is needed. Below that the WiiM Amp Ultra will probably have an edge, but not a massive one, since it's maximum output into low loads is finally limited by it's PSU. Generally speaking, PBTL is better than BTL, of course.

 

[john61ct]

It depends of the definition of "equivalent"

OK thanks, as a man on a mission I would still go with A7 Mono per speaker, and an oversized PSU.

Can you recommend a domestic USA ordering source, ideally non-Bezos?

But so far my second choice, only if it turns out there is a downside to standardising on multiple Wiim Amp Ultra, even for within the same system.

Seems at this point the latter is the "value no-brainer".


> Generally speaking, PBTL is better than BTL, of course.

Is that true other than SPL current / power issues?

...
What do y'all recommend for accurate SPL metering at low cost?

 

[ziggurcat]

OK thanks, as a man on a mission I would still go with A7 Mono per speaker, and an oversized PSU.

Can you recommend a domestic USA ordering source, ideally non-Bezos?

But so far my second choice, only if it turns out there is a downside to standardising on multiple Wiim Amp Ultra, even for within the same system.

Seems at this point the latter is the "value no-brainer".


> Generally speaking, PBTL is better than BTL, of course.

Is that true other than SPL current / power issues?

The only US ordering source for the A7 is Amazon, I'm afraid. AliExpress is the only other place, outside of one French retailer, AFAIK.

 

[Alannn]

> Generally speaking, PBTL is better than BTL, of course.

Is that true other than SPL current / power issues?

3e Audio gives us a great opportunity to compare BTL to PBTL since all else is kept equal.

Above chart shows BTL has better thermal performance. Perhaps that affects reliability and service life. We know BTL better thermal performance can't hurt.

Chart also shows BTL is better value than PBTL. This is debatable based on buyer's desire for better specs and also speaker impedance demands. We know BTL is cheaper.

 

[john61ct]

The only US ordering source for the A7 is Amazon, I'm afraid. AliExpress is the only other place, outside of one French retailer, AFAIK.

Thanks. Any lead on a trustworthy Ali seller ?

 

[john61ct]

So those factors say, for a speaker pair, sightly better to use A7 Stereo than 2x Mono's ?

Besides speaker impedance demands, and being cheaper...

Would that still be true for different speakers, say a 10" subwoofer off one output, and a center off the other? Even if power requirements were grossly mismatched?

Above chart shows BTL has better thermal performance. Perhaps that affects reliability and service life. We know BTL better thermal performance can't hurt.

 

[ziggurcat]

Thanks. Any lead on a trustworthy Ali seller ?

There's only one:

https://www.aliexpress.com/item/1005007964184254.html?spm=a2g0o.productlist.main.1.7d5a464bL4MWJy

You select the "color" you want from the images (the US SKU is going to be one of the ones with the flame icon in the upper right corner).

 

[antcollinet]

View attachment 475574

3e Audio gives us a great opportunity to compare BTL to PBTL since all else is kept equal.

Above chart shows BTL has better thermal performance. Perhaps that affects reliability and service life. We know BTL better thermal performance can't hurt.

Chart also shows BTL is better value than PBTL. This is debatable based on buyer's desire for better specs and also speaker impedance demands. We know BTL is cheaper.

PBTL is mainly providing the ability to deliver more current - this will only apply with speaker loads where the speaker impedance dips below 4 ohms. The table doesn't show this.

PBTL will be able to deliver more current into low impedance dips - preventing clipping at those points.

 

[Alannn]

PBTL is mainly providing the ability to deliver more current - this will only apply with speaker loads where the speaker impedance dips below 4 ohms. The table doesn't show this.

PBTL will be able to deliver more current into low impedance dips - preventing clipping at those points.

In the "speaker load" column of the table, the entries "2-16 ohms" explicitly implies the ability to deliver more current at 2-4 ohms for PBTL models. The basics of electricity allow that for a given rated power, lower impedance requires more current. This is a given.

 

[john61ct]

Could someone explain "damping factor"?

related to PBTL, makes it better, correct?

Which direction is better and why, how does it relate to other factors, in what context is it meaningful ?

 

[antcollinet]

In the "speaker load" column of the table, the entries "2-16 ohms" explicitly implies the ability to deliver more current at 2-4 ohms for PBTL models. The basics of electricity allow that for a given rated power, lower impedance requires more current. This is a given.

But unquantified. There is no power rating given for less than four ohms. Does it double at 2 ohms? Or less than that - from the table, we don't know.

 

[Alannn]

There is no power rating at 2 ohms because 2 ohms is usually a minimum speaker impedance, not nominal. And more importantly, speaker impedance phase angle greatly effects demands put on an amplifier. A power rating at 4 ohms just provides a simple way of comparing different amps.

Power output at 2 ohms is something measurable in a lab. It's not relevant to what your amp is doing playing music through speakers that momentarily hit that 2 ohm minimum at a certain frequency.

 

[antcollinet]

There is no power rating at 2 ohms because 2 ohms is usually a minimum speaker impedance, not nominal. And more importantly, speaker impedance phase angle greatly effects demands put on an amplifier. A power rating at 4 ohms just provides a simple way of comparing different amps.

Power output at 2 ohms is something measurable in a lab. It's not relevant to what your amp is doing playing music through speakers that momentarily hit that 2 ohm minimum at a certain frequency.

I agree. I am simply pointing out that the degree of benefit provided by PBTL is not determinable from that table.

You need this test result to see it:

 

[Alannn]

I agree. I am simply pointing out that the degree of benefit provided by PBTL is not determinable from that table.

You need this test result to see it:

Yes on this forum, we love test results. I own an A5se and at the time ASR tested the A7, I asked 3E Audio to send the BTL model to Amir for testing. That would have been a prime comparison of PBTL vs BTL.

On the other hand, the table helps address the @john61ct question of differences "other than SPL current / power issues."

 

[Human1]

Dumb question, I assume the 5 amp psu is fine for the mono version of the amplifier? The 10 amp would really only be needed for the stereo amp?

 

[SMen]

Dumb question, I assume the 5 amp psu is fine for the mono version of the amplifier? The 10 amp would really only be needed for the stereo amp?

I think it is an interesting question. In fact the supplied 48v 5A works fine for the stereo but (you can put this down to listening bias if you want) the 48v 10 is a keeper for me with the stereo A7 as I move into Autumn and less than 30+C ambient temperatures.

2x 48v 5A power supplies ... I am sure someone here can do the technical mathematics as to how this differs vs 48V 10A into stereo... but with the 2x 5amp psu's you must be pretty equivalent to all the super happy users of the 10A (or indeed 5A) into the stereo A7!

 

[Maniek]

Głupie pytanie. Zakładam, że zasilacz 5 A wystarczy do monofonicznej wersji wzmacniacza? Czy 10 A naprawdę będzie potrzebny tylko do wzmacniacza stereo?

2*48V/5A -2*3e Audio a7 mono
1*48V/5A 3e Audio a7 Stereo
1*48V/10A 3e Audio a7 (speaker 2….ohm min…)

 

[john61ct]

Do not run parallel PSUs to a single load.

Better and safer to use a single, properly rated power supply

Some more expensive/commercial PSUs are designed for parallel operation but...

You only "need" the higher power input under limited, relatively rare conditions

related

J

Post in thread 'Wiim announce WiiM Amp Ultra'

Aug 25, 2025

Excuse me, is this Wiim Amp Ultra more powerful than the Wiim Vibelink?

Absolutely yes. But nothing you would notice, unless you really are trying to get max (safe) SPL AND

A. your speakers are hard to drive

B. with varying impedance, e.g. rated 8ohm nominal but in reality go down to 3-4ohm

big drops can cause current overload / overheating and create distortion even if watts are OK, voltage drops when the amp can't deliver enough CURRENT

Most people will not be dealing with all of these edge case conditions at the same time, but for those that do,

the dual-mono 1-chip per...

• john61ct

 

[Human1]

Do not run parallel PSUs to a single load.

Better and safer to use a single, properly rated power supply

Some more expensive/commercial PSUs are designed for parallel operation but...

You only "need" the higher power input under limited, relatively rare conditions

related

J

Post in thread 'Wiim announce WiiM Amp Ultra'

Aug 25, 2025

Excuse me, is this Wiim Amp Ultra more powerful than the Wiim Vibelink?

Absolutely yes. But nothing you would notice, unless you really are trying to get max (safe) SPL AND

A. your speakers are hard to drive

B. with varying impedance, e.g. rated 8ohm nominal but in reality go down to 3-4ohm

big drops can cause current overload / overheating and create distortion even if watts are OK, voltage drops when the amp can't deliver enough CURRENT

Most people will not be dealing with all of these edge case conditions at the same time, but for those that do,

the dual-mono 1-chip per...

• john61ct

I'm not sure I understand what you mean by parallel. I'm talking about a 10 amp psu with one mono amplifier. Is this a problem, is it even beneficial? Are you saying two mono with two 10amp psu in one outlet is an issue? Or somehow jury riggin two 5 amp psu together for one mono amp is a problem?

 

[john61ct]

yes. Parallel means two PSUs feeding a load, plus to plus, neg to neg.

In series is also not straightforward, just use a single PSU.