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AIYIMA A07 TPA3255 Review (Amplifier)

maxxevv

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You do realize the IC specifications and the completed Aiyima product are two completely different things?

TI use a 51V supply, THD at 10% and clearly a power supply that would cost multiples of the price of this Aiyima thing. Then for the maximum 8R spec they use a 53.5V supply.

The completed product being sold and reviewed here, as supplied, cannot achieve its rated specs. Not even remotely close. It is the customers that buy based on published specifications that are being deceived and ripped off.

This brings up a question I am having.

Has anyone tried powering the A07 board with a dedicated 48V power supply with a real rated 500W+ and measured the output of the resultant combination ? Would we get over 200W per channel?
@amirm 's test basically use power supplies that only have 160W in the total output to drive the amp though and we do get close with 77W ( 154W total) per channel at 4 Ohms using one of the power supplies didn't we ? What if the power supply for the 48V 3A one was a bogus rating, hence its less than good showing in the measurements ?

Of course, the TI chip would need far better cooling solutions to run at that kind of power pushed. Possibly a computer chip cooler would be needed.
 

pma

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This brings up a question I am having.

Has anyone tried powering the A07 board with a dedicated 48V power supply with a real rated 500W+ and measured the output of the resultant combination ? Would we get over 200W per channel?
@amirm 's test basically use power supplies that only have 160W in the total output to drive the amp though and we do get close with 77W ( 154W total) per channel at 4 Ohms using one of the power supplies didn't we ? What if the power supply for the 48V 3A one was a bogus rating, hence its less than good showing in the measurements ?

Of course, the TI chip would need far better cooling solutions to run at that kind of power pushed. Possibly a computer chip cooler would be needed.

Yes and I posted the results
https://www.audiosciencereview.com/...-measurements-and-review-lm4562-option.19155/

however you guys do not care about real engineering info and ask for simplest (and wrong) answers. And do not care about searching info. It is both annoying and frustrating.
The amp is able of 170W/4ohm power before clipping, but only short-term. At 100W/4ohm, protection circuits shut it down after about 1 minute.

I am aware of the fact that after next page the same question will arise again.
 
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Raindog123

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however you guys do not care about real engineering info and ask for simplest (and wrong) answers.
We guys do care about real engineering. And follow and appreciate your measurements and thoughts too... But many of us are also fascinated by a $50 marvel with a $15 power brick that objectively and subjectively sounds as good/better than our multi-thousand racks. And despite some silly “48V 10A PS fishing expeditions”, no one here plans to use A07 to furnish a next Woodstock. Rather, enjoying 10W/chan or so at home. So, some in this topic are interested taking the TI chip to ”the engineering limits/heights”... while some are genuinely interested in the “consumer/user” aspect.


I am aware of the fact that after next page the same question will arise again
This is the nature of humans. Some of us sit here for days and read every friggin post in a 50-page thread... While others see an interesting topic title, read a [first/last] page or two and post their thoughts... (And some are able to carry on a civilized conversation, while others constantly spew intolerance and agitation...)
 
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Ralferator

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They are not remotely 'superb'. That's just complete BS. Not even good. Low price is not an excuse where fidelity is concerned.

People really need to stop talking up this little toy amplifier as being anything other than a 'my-first-amplifier' for a kids bedroom or maybe an amplifier for a dorm room at college. Nah, not even that. I had serious amplifiers in my college room back in the day.

Maybe for true hifi-snobs this is a toy amplifier. For anybody else this can be good enough for a hifi system. Not everybody is a hifi-snob or has thousands and thousands to spend.
By the way - did you even listen to this amplifier in your system and made a blind test? I guess not
 

Bruce Morgen

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At 100W/4ohm, protection circuits shut it down after about 1 minute.

I have no doubt of that if the input is a test tone and the amp is driving dummy loads. When playing actual music, 100+ WPC peaks are handled nicely, which can happen when for the most part the amp is putting out an easily sustainable 10-20 WPC. That's what using a hefty PSU with an A07 is for in the real world -- those brief intervals of high power demand. A minute at a steady 100 WPC is deafening with -- and likely to be damaging to -- virtually any speaker typically used with a $50 amp.
 

imagidominc

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I'll just say this: the amplifier I WANT costs $4,000+. But I don't have the disposable income to spend that on Hifi right now. So I bought this little amp to hold me over in the meantime. It's well within my budget and allows me to listen to my music on my killer speakers (Elac Debut Reference). I have a small room and the sound is plenty loud and dynamic. Having an amp, even a small entry level one like this, is better than waiting around for one I won't be able to afford for a while.
 

Bruce Morgen

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The thing about the A07 that impresses me is how much more one has to spend in order to get a significant improvement over its performance given an adequate PSU -- the price jumps from well under $100 USD to several hundred before there's an audible difference that can confidently be called "better." Frankly, in the Class D realm I think you've got to venture well into Purifi/Hypex/ICEPower territory before that happens -- and IMO that's pretty danged remarkable for "a toy" that costs a literal pittance.
 
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GGroch

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IMO it was obviously a seller posting error in the first place.
My $23 toy amp order just shipped via YunExpress. ;)

Amazon penalizes the metrics of Marketplace vendors for not shipping items, so perhaps it has shipped even though it was a mistake. I won't be certain until it arrives.

This gives me plenty of time for a power supply search. The Douk Audio/Nobsound 24v-5a would be plenty for my use I think and appears to be the appropriate quality. I will continue browsing for a 32-36v.
 

remlemasi

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My $23 toy amp order just shipped via YunExpress. ;)

Amazon penalizes the metrics of Marketplace vendors for not shipping items, so perhaps it has shipped even though it was a mistake. I won't be certain until it arrives.

This gives me plenty of time for a power supply search. The Douk Audio/Nobsound 24v-5a would be plenty for my use I think and appears to be the appropriate quality. I will continue browsing for a 32-36v.

Same! And to think I hesitated on purchasing it at $23 shipped...
 

mihvas

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I bought 07 from AiyimaTechnology Store and it doesn't work - no light, no sound. PSU 28V 10A, + inside. Seller keeps silent. Open a dispute.
Can be a DC resistor burned?
 

Lambda

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Lambda

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You mean to say 36V right?
I meant to say 48V gives more dynamic and peak power but 36V gives more efficacy

Reasoning:
1. Higher voltage gives more headroom
2. At higher voltage more voltage drop at peak is acceptabl
3. Energy stored in the capacitors is:

1615830620054.png


So more voltage gives exponentially more energy. for short high power pulses.
 
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remlemasi

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I meant to say 48V gives more dynamic and peak power but 36V gives more efficacy

Reasoning:
1. Higher voltage gives more headroom
2. At higher voltage more voltage drop at peak is acceptabl
3. Energy stored in the capacitors is:

View attachment 118377

So more voltage gives exponentially more energy. for short high power pulses.
Got it. Just to confirm, I am looking at a 42V 4A power supply, not 48V, but the fundamentals still apply. Higher voltage = more headroom (assuming sufficient current). Looking to stay away from 48V as some have reported significantly higher heat and the A07 not being properly designed to handle 48V.
 

Lambda

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more headroom (assuming sufficient current)
The current is not impotent. the power is. Watts.
Short peak current is anyway mainly supplied by the capacitors.

some have reported significantly higher heat and the A07 not being properly designed to handle 48V.
Yes. less efficiency means more heat and lower sustained power.
 

Raindog123

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...but from these, which one is a better fit?

I am with @Lambda:
...48V gives more dynamic and peak power but 36V gives more efficacy


Assuming you have a reasonably sensitive (86+dB) 6 or 8 Ohm speakers, and that you room is not too huge -- so you do not need too high of a sustained power, then:

If you do not mind [5-10 degree?] warmer amplifier and want slightly punchier bass, go with your 42V choice. If you want your amp somewhat cooler, go with 36V.... Or, buy both and check if there is any difference in sound (and return less-favorite to amazon).
 
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remlemasi

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What speakers (impedance and nominal power) do you have? How far from the speakers are you during your listening sessions?

Primary use case will be some old Polk R15 bookshelf speakers on my desktop (<1m away), 8ohm, 89dB sensitivity. However, I want to be able to drive something as inefficient as Polk LSi9 in the future, which are 4ohm, 88dB sensitivity, at >2m away. Basically, I know I don't need the power now, but want to get something that will cover even full range 4ohm speakers if I need to (I have LSi15 floor standing speakers in my main system).
 
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