AIYIMA A07 TPA3255 Review (Amplifier)

[DuncanTodd]

Just FYI, the Aiyima rep stated that they are working on a new versions of the A04 and A07 that will have an internal PSU and possibly take into consideration other improvements suggested by ASR members. They said it will happen at the end of 2020:
https://www.audiosciencereview.com/...at-functions-do-you-hope-to-add-to-a07.16787/
They have another very similar looking product with some added features, but say that isn't the new A07.

 

[Bruce Morgen]

Just FYI, the Aiyima rep stated that they are working on a new versions of the A04 and A07 that will have an internal PSU and possibly take into consideration other improvements suggested by ASR members. They said it will happen at the end of 2020:
https://www.audiosciencereview.com/...at-functions-do-you-hope-to-add-to-a07.16787/
They have another very similar looking product with some added features, but say that isn't the new A07.

I hope the versions under development will include a power supply and thermal management commensurate with the performance potential of the chip. I will add my request to that thread -- thanks for sharing the URL.

 

[daniboun]

I hope the versions under development will include a power supply and thermal management commensurate with the performance potential of the chip. I will add my request to that thread -- thanks for sharing the URL.

A quick little research will already give you the answer ... And frankly, I strongly advise against their new Aiyima amp whose promises have not been kept ... just take a look at the caps, inductors and very dangerous design....etc and you will understand (


https://fr.aliexpress.com/item/1005...earchweb0_0,searchweb201602_,searchweb201603_

 

[DuncanTodd]

A quick little research will already give you the answer ... And frankly, I strongly advise against their new Aiyima amp whose promises have not been kept ... just take a look at the caps, inductors etc and you will understand (


https://fr.aliexpress.com/item/1005...earchweb0_0,searchweb201602_,searchweb201603_

They said it's not the new one:
https://www.audiosciencereview.com/...amp-do-you-recommend.9148/page-35#post-606410

 

[Bruce Morgen]

A quick little research will already give you the answer ... And frankly, I strongly advise against their new Aiyima amp whose promises have not been kept ... just take a look at the caps, inductors and very dangerous design....etc and you will understand (


https://fr.aliexpress.com/item/1005...earchweb0_0,searchweb201602_,searchweb201603_

I have no interest in the product to which you've linked. I already own two recent A07s like the one Amir reviewed and am perfectly happy with their performance, especially considering their price. As Duncan has pointed out, the product with which you're understandably disappointed isn't the one currently under development. Peace.

 

[karrtoons]

I'm so happy to see this review, as I've been listening to this bargain amp for a few weeks not knowing how it really measures up. I have it paired up to some KEF Q150s, and am very pleased with the setup. Turning the unit on, there is a 1 second delay before it comes to life with no pops or unexpected noises. Turning it off, the output ceases immediately. There is a very slight hiss when the input is muted, but it's only audible with my ear pressed against the tweeter - something you'd never hear from a listening position. There is also a slight imbalance at low volumes, which I was expecting, and all the more reason to crank this thing up. Using an alternate PSU, I think you'd be very hard pressed to find something that sounds as impressive under $100, especially within a quart sized package. Indeed money well spent.

For those deciding between the A04 and A07, the A04 available on amazon does not include a power supply. As Amir has mentioned, the A07 does, and that easily makes it worth the extra $20. I had originally ordered an A04 based on some ACR forum praise, but that unit suffered from turn on pop from a faulty anti-pop circuit. I ordered a second that works as expected, so these things are not without QC issues. Ultimately, I have opted for the A07 as it out outputs quite a bit more into 8 ohm loads, and the THD performance is close enough between the TPA355x chips.

The 32V 5A supply that is provided is better suited for the A04. I have opted to power the A07 using a 350W meanwell supply from mouser (whudda deal at $32): meanwell LRS350-48V. I also purchased some 16awg DC plug pigtails from amazon to make things easy. The 50V electrolytics do not leave a lot of wiggle room for a 48V supply, but this one regulates down to 42V. I think it's good to leave some safety margin considering the unit runs hotter at higher voltages and the caps are right next to the heatsink. I've yet to hear the smps fan engage, and both the A07 and meanwell run quite cool during extended playing. I do not measure any mains hum at the meanwell output, and am definitely curious how this supply or other reputable supplies would impact the SNR.

 

[DuncanTodd]

I have no interest in the product to which you've linked. I already own two recent A07s like the one Amir reviewed and am perfectly happy with their performance, especially considering their price. As Duncan has pointed out, the product with which you're understandably disappointed isn't the one currently under development. Peace.

The confusion is quite understandable because some weeks prior to this, the rep posted a video of this new product saying it's the new A07. From what I've seen the rep is more a PR person. He'd pass questions and answers back and forth from forum to their techs and vice versa.

 

[DuncanTodd]

I'm so happy to see this review, as I've been listening to this bargain amp for a few weeks not knowing how it really measures up. I have it paired up to some KEF Q150s, and am very pleased with the setup. Turning the unit on, there is a 1 second delay before it comes to life with no pops or unexpected noises. Turning it off, the output ceases immediately. There is a very slight hiss when the input is muted, but it's only audible with my ear pressed against the tweeter - something you'd never hear from a listening position. There is also a slight imbalance at low volumes, which I was expecting, and all the more reason to crank this thing up. Using an alternate PSU, I think you'd be very hard pressed to find something that sounds as impressive under $100, especially within a quart sized package. Indeed money well spent.

They added a pop prevention circuit, that's why the second one you got had no issues.
I noticed the slight hiss when muted and ear hard pressed against the tweeter. I asked about it on the thread and I believe it was daniboun who said it's completely silent for him. He has made some modifications though, so that may have gotten rid of it. The amp itself gets warm(ish) to the touch after a while when turned on .

 

[wwenze]

The following link is to a site that has previously been referenced in this thread. Various measurements of the TPA3255 mounted in a TI evaluation module were performed, to include output impedance. If you scroll down nearly to the bottom, you will see the graph of the output impedance. It appears to be very good, below .2 Ohms until reaching mid-treble, then climbing to .5 Ohm at 10 kHz and 1.8 Ohm at 20 kHz. A 4-Ohm speaker's share of the output voltage will be 95% throughput most of the frequency range. This will fall to 89% at 10 kHz, and to 69% at 20 kHz. Suppose the speaker's impedance rises to 30 Ohms at the driver resonances, which is a very reasonable, typical value. The speaker's share of the output voltage will now be 99%. Relative to 95%, the power gain in dB, the calculation of which involves squaring the voltage ratio, is .4 dB. This probably isn't enough to bother me, but for some people .4 dB is enough to matter. And it exceeds the deviation that would likely be deemed acceptable were it encountered in the amplifier's frequency response. And please keep in mind that this is a TI evaluation board.

So, your concern is the 0.2 ohm output impedance. Or a damping factor of 20 with a 4ohm load.

Fair enough. If the AP has the capability to measure speaker amp output Z, it is a good thing to have. I mean we have those measurements for headphone amps so...

Class AB amps can have poor damping factors too, so this is not a class-D specific issue.

 

[johan]

With dual Tpa 3255 in PBTL mode and post filter feedback with a good power supply, it should be possible to get a SINAD better than 100 ?
ALLO where are you ?

https://www.ti.com/lit/an/slaa788a/slaa788a.pdf?ts=1609438992194&ref_url=https%3A%2F%2Fwww.ti.com%2Fproduct%2FTPA3255

Here , working on the TPA3255. My 3 revision of the PCB. Yes better than -100 Sinad already achieved .

 

[Biblob]

Here , working on the TPA3255. My 3 revision of the PCB. Yes better than -100 Sinad already achieved .

Can you say when this one will be available?

 

[Patrickbateman]

Just a little question: which one is better between a07 and this one https://fr.aliexpress.com/item/32996463571.html?spm=a2g0w.12010615.8148356.5.ba60240572IZEw

This one has bluetooth, 2200UF/63v but no op amp, so, what is better ?

Is it better with op amp ?

I am actually using this one https://fr.aliexpress.com/item/32990257891.html?spm=a2g0w.12010615.8148356.7.ba60240572IZEw
with a meanwell 40v, it's working fine, but again what does it worth against a07 ?

I'm not sure about using mine at 48v ( Working voltage: DC30V-48V (inside + outside - 5.5*2.5MM) recommend to use DC30V 6A(Max DC48V 8A) )

What do you think ?

Sorry for the maybe stupid questions, i'm here to learn. ;-)

 

[Ariamella]

That is a good advice in general but here, you need a high voltage one to produce as much wattage as this can (32 volt+) . There are no laptops that need such a high voltage (19 volts is typical). I found some HP printer power supplies that have high voltage but very low current so that won't do either.

That's why I specified the meanwell ones too, they come in higher voltage varieties if one desires but are a bit harder to get than your standard laptop brick

Edit: Though thinking about it a little more, one might have to cut off the DC connector and solder in a normal barrel plug hmm hmm...

 

[MediumRare]

A quick little research will already give you the answer ... And frankly, I strongly advise against their new Aiyima amp whose promises have not been kept ... just take a look at the caps, inductors and very dangerous design....etc and you will understand (

I’m not an engineer so could you point out the things you’re seeing, especially the risky characteristics?

 

[Bruce Morgen]

Here , working on the TPA3255. My 3 revision of the PCB. Yes better than -100 Sinad already achieved .

What are the power supply requirements and will you be offering one powerful enough to unlock the chip's enormous potential?

 

[karrtoons]

I’m not an engineer so could you point out the things you’re seeing, especially the risky characteristics?

I might be able to address some concerns. The case doesn't look earthed. There is not much clearance for the mains supply to the PSU, and fuse protection appears to be missing. The spacing of the inductors and the heatsink look very tight, and there's potential for shorts if things run hot. Like many budget amps and supplies, they're not sourcing components from reputable brands - no name capacitors may not perform well over time at rated voltages or temperatures.

 

[TheWalkman]

I might be able to address some concerns. The case doesn't look earthed. There is not much clearance for the mains supply to the PSU, and fuse protection appears to be missing. The spacing of the inductors and the heatsink look very tight, and there's potential for shorts if things run hot. Like many budget amps and supplies, they're not sourcing components from reputable brands - no name capacitors may not perform well over time at rated voltages or temperatures.

My impression of dangers discussed in Amir’s review was with the power bricks, not the amp itself.

Amir - can you clarify, please?

 

[karrtoons]

My impression of dangers discussed in Amir’s review was with the power bricks, not the amp itself.

Amir - can you clarify, please?

My comment is referring to the newer aiyama amp with the integrated psu (post #143)

 

[TheWalkman]

My comment is referring to the newer aiyama amp with the integrated psu (post #143)

My bad! Thought you were referring to the 07.

Cheers

 

[TheWalkman]

Buyer beware!

Based on the discussion here, I broke down and ordered an Aiyima A07 from Amazon and despite the listing clearly stating that a power supply was included, it was not. (See post#121)

That stinks.

At least I didn’t have to wait 6 weeks for a slow boat from the Orient (and deal with a return to AliExpress.....)