AIYIMA A07 Max: Overrated or Underrated?

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[trudimcleod]

My understanding is that mono mode requires more current than 5A, since you are basically maxing out on the power of the TP3255. This is also why your stereo power rating is coming closer to the Aiyima and the chip specs, you are maxing out on voltage. The other consideration is the THD+N at 5W output into 4 ohms, which is pretty good and has been measured by ASR.

[ervinleblanc]

I like that you’re reviewing and testing things at all price ranges. Thanks Erin!

[ishonk]

The high wattages are provided by TI's datasheet of the TPA3255 and measured at 10%THD+N:
315-W Stereo into 4 Ω in BTL Configuration
185-W Stereo into 8 Ω in BTL Configuration
600-W Mono into 2 Ω in PBTL Configuration

Total Output Power at 1%THD+N (according to TI):
260-W Stereo into 4 Ω in BTL Configuration
150-W Stereo into 8 Ω in BTL Configuration
480-W Mono into 2 Ω in PBTL Configuration

[robertfiorellino]

My Cambridge amp was out for repair and I was told it would take at least four weeks for a new motherboard to arrive (warranty). So I purchased two of these Aiyima A07 max amps to fill in. There are being fed by a 30 year old Forte F45 preamp and driving my KEF LS 50 Metas. They sound very good. They reach the listening levels I am comfortable with and I'm not aware of any distortion. Very happy after two weeks.

[markmeridian]

I trust your reviews much more than anyone who doesn't do blind listening tests.

[kellybest]

Erin. I appreciate your work. You are literally the best audio reviewer on the web. It's to to point that if you like something, I know I will too. Thanks.

[Eron]

Use these with my Lintons. Bliss if you ask me. Brings em to life. I also found they brought my Elac UB52's alive as well.

[carvern]

Check out the RSL class D amp. iA255. They have a sub out and a high pass filter switch.

👍👍👍Kudos to Erin for taking the 300W+300W figures to task ! Habitually these tiny Class D "giants" claim a high output wattage at 4 ohms with a 10% THD. Why anyone would care about the amp's output at this astronomical distortion level is beyond me. All being said $75 for a well built desktop amp with 90wpc rms quality sound into 8 ohms is still a helluva bargain by any standard. Kudos to Aiyima and Fosi ! 👍👍👍

[literalghost]

How good is the audio quality though when compared to normal class AB amps? Schiit Vidar for instance is $800 bucks, probably similar power, how different do they sound?

[Douglas_Blake_]

Oh boy ... here we go again...

First ... that A07Max will hit 300 watts ... at 10 % distortion. Even more in PBTL (mono) mode on a 2 ohm load. (using a 48 volt 10 amp bench supply)

Now... look at the casing for that amplifier. This is a chip on the bottom design. But look at the ventilation they provide. Air intakes on the bottom, outlets on the sides. Open holes with no obstructions to convective cooling. Unlike their competition, they're not simply heating up the case. They are providing a way to get the heat out of the case as well. This is crucial to keeping things sane during prolonged loud sessions.

Also, having done deep dives in both companies designs, I have found that Aiyima takes a lot more care in their designs. Overall these amps have better (cleaner) logic and pre-amp power supplies and they tend to have better protection circuitry as well.

Now about this load dependency thing...
With due respect to the measurement guys, this has to be the most overblown issue I've seen in a long long time. They are arguing about fractions of a decibel here... Elevate that to a normal listening level of 80db... those graphs represent about 79.5 db to 80.6 db variation ... *nobody* is going to actually hear that.
Moreover; if they zoom out to show a full 80db spl, it would graph as a straight line.
This is the royal tempest in a tea cup and it's about time to stop making such a big deal out of it.

There is a deal breaker in this design: the power switch on the volume control. If you are running these as a dual monoblock setup, good luck re-balancing the sound every time you turn them on. Without a Trigger input, you're going to have a problem keeping your LR balance.

Is this better than the V3, ZA3 or the V3M ... yes. Plain and simple.
But for my money the original A07 is still the best of the bunch.

All that said, this is still a very powerful chip in a remarkably small enclosure. To avoid thermal shutdowns, I recommend that you stick with 36 volt 5 amp power bricks.

[dipolito]

Lol, in the title I read overheated instead of overrated 😂

[kenandbarbie-bc]

How are these Chinese amps so inexpensive? There is a manufacturing video on YT that shows how Fosi audio builds them. Most of the production is automated (not sweatshop slave labor) except for some of the final assembly. The stereo Texas Instruments Class D amp integrated circuit (TPA3255) that many of these amps are built around only cost about $5.00! This is just as much a TI innovation. The choice of high quality component parts rounds off some of these products, making them competitive. Yes, with a quality $5.00 chip, low prices are possible.

Much of the specs of these amps come straight from the Texas Instruments data sheet.

[Douglas_Blake_]

From the video ... How do they make these things so cheap?

Mass production, bulk purchasing, low parts counts, automated assembly, low labour costs... but dominantly, the total lack of the typical "audiophile markup". These guys aren't trying to get their year's income out of 150 units... they're selling literally tens of thousands of these every year so the cost of business is widely distributed across all of it.

[duroxkilo]

you hear people in the pro-audio world calling it "modern watts" when measuring class D amps and it's not what i thought.

at first it seems a bit of tongue in cheek but i've looked into it and it's a legit way of measuring field/deployed max power in 'modern amps'. w/ traditional resistive load tests, comparing class AB to D max power is not an apples to apples comparison.

long story short, they measure peak power in short bursts because apparently in real world situations as long as the amplifier's peak power sustain duration is longer than the peak attack duration of a sound being reproduced, that is enough to produce the advertised max average wattage -and the SPL meters do measure the amp's advertised max power. (a reserve vs demand scenario)

class D is great at providing short bursts of high power but not great at sustaining that peak power, so the question is 'how long does the amp need to provide peak power to actually be louder?'... class AB pro amps can have identical max and peak power but at a lower value than class D burst peak...

i've seen power density comparisons between AB and D class where the max voltages show class D under-performing while measured in resistive loads over a period of time (like automatically increasing a test signal until the amp reaches a preset distortion %), but the max and average power output w/ bursts or program content has the class D amps hitting the actual specification marks, far outperforming class AB in power density.

i might be misremembering the numbers, but i think as long as the burst peak power duration is like 200-300ms, that's long enough for the measured average SPL to be in fact in agreement w/ the amp's wattage -even w/ bass heavy content such as dnb music.

i'm not saying that is the case w/ this product, i'm just sharing something i've learned not long ago about the 'modern watts' and why pro class D amps seem to under-perform under traditional voltage tests but are right on the money in real world conditions. would be great to see the concept tested in the non-pro audio realm too...

[avnut]

Great value for sure.
It actually does better than I expected.
Would I buy it? No.
Thank you for your detailed review and transparency

[uribar-ner]

Did anyone try these amps using 48v 10a in mono mode?

[RobertCookcx]

I have twin A07's (not the max) running active to some home brew 2-ways using the Dayton 408 DSP. I did upgrade the preamps with some sparkos chips. Very happy with the performance of them.

[seank]

Thanks Erin. You are in the ultra rare ranks of reviewers who do blind testing. I value that.

[TechnikToni-Overtribe]

Should keep in mind on those amps normally the used Chip (TPA3255) is a 4 channel chip capable of driving 4x 2ohm loads but in this case when used stereo channels 1/2 and 3/4 get bridged already making it a full bridge amp capable of driving two 4 ohm loads minimal, now when you go to full mono mode those two already bridged channels get paralleled up again shown as PBTL in the TPAs Datasheet making it capable of driving single 2 ohm load where you would get maximum potential going by your measurements about 350watts at 2ohm

As we know when running somthing in parallel voltage doesn’t change just the current capabilities get increased so if you run full mono/PBTL mode at 4/8ohm you won’t expect much more power then running 2 channels each at 4/8ohm cause the voltage when paralleled stays the same, there may be a slight bit more power but that’s due to the channels sharing the load so each channel effectively sees 16ohm in 8Ohm PBTL mode or 8Ohm when in 4Ohm PBTL mode