AIYIMA A07 TPA3255 Review (Amplifier)

[antcollinet]

I don't think this is true -- at least every post-Y2K powered sub I've encountered has its speaker level inputs isolated from each other. Surely there would be some sort of warning notice in sub manuals about that since, as you pointed out, it "could damage the amp."

It's a bit of a hangover. It is only in the recent world of low cost chip based class D amps where BTL is common. Many Sub manufacturers have not yet caught up with this situation.


EDIT - just as an example. thjs is the warning given in my sub manual...

And this from an article on REL's website here:

Brick by Brick | REL Acoustics

Our hifi stereo systems are made of individual pieces, and each of these pieces represents an individual buying decision.

rel.net

 

[pma]

A07 has the volume pot before the active circuitry. So, no worries.

 

[Bruce Morgen]

It's a bit of a hangover. It is only in the recent world of low cost chip based class D amps where BTL is common. Many Sub manufacturers have not yet caught up with this situation.

Thanks, Ant -- I think your sub and Rel's might be outliers, though. I just checked my 20-year-old Infinity PS-10, and the relevant binding posts are duly isolated from each other.

 

[antcollinet]

Thanks, Ant -- I think your sub and Rel's might be outliers, though. I just checked my 20-year-old Infinity PS-10, and the relevant binding posts are duly isolated from each other.

Are the black ones isolated from earth and from each other? That is where the problem lies.

 

[Mark Lawless]

I'm guessing 4 ohm speakers, right? This amp, like the SMSL A300, specs rather poorly, but somehow many find great sounding. Go figure!

After comparing the aiyima 07 to my other amps. I have to say it does sound good but it does come up short comparing it to much more expensive amps.

 

[Bruce Morgen]

Are the black ones isolated from earth and from each other? That is where the problem lies.

Yup.

 

[rintintin78]

Use 19V/3.4A notebook power supply. I tested it: post #49

AIYIMA A07 TPA3255 amplifier with MW RS-100-24 SMPS power supply (measurements)

Why do we have zero to few, if any sources for enclosures for these open cage units? Because these units are primarily intended for industrial automation and IT technologies and are built in caseworks of the completed gear.

www.audiosciencereview.com

You are just below 50W.

but is it 20watts per channel?

 

[pma]

You wanted the power limited at 50W. So it goes, you have it limited at 50W/THD10%. The plot shows.

 

[rintintin78]

You wanted the power limited at 50W. So it goes, you have it limited at 50W/THD10%. The plot shows.

sorry, maybe it's my English fault. But I wanted to limit everything to 50 Watts RMS into 4 ohms per channel for a total of 100 Watts RMS into 4 ohms

 

[magreen]

The aiyima has a "splitter". The RCA inputs and the 3.5mm input are both pass through outputs when using the other one. As in, if you connect RCA inputs to the Aiyima, you can use the 3.5mm as an out. Or if you connect via 3.5mm, you can use the RCA's as outs.

Hi. Sorry for the blast from the past. I just wanted to add my findings regarding the 3.5mm AUX out of the A07. It's not as simple as a splitter or Y cable, though it sort of functions that way. I just tested the "AUX 3.5" out on my original A07 with a multimeter and also a subjective listening test. I plugged cables in and measured a resistance of 1000 Ohms from the RCA center pins to the tip/ring of the 3.5mm AUX out. Identical resistance on both channels. So the signal is passed but with some resistance and who knows what else. The 1 kOhm resistance is there unchanged whether the unit is on, off, plugged in, or not plugged in, volume up or volume down.

For a subjective listening test, I ran the output from my DAC/pre-amp into the RCA inputs on the A07, and then the AUX out to the amplifier of my good stereo system. (In other words, not using the A07 for amplification -- just as a pass-through.) I found that it sounded good, but not as good as running the DAC straight into my amplifier. Something is being done to the signal/sound.

 

[Bruce Morgen]

I just wanted to add my findings regarding the 3.5mm AUX out of the A07. It's not as simple as a splitter or Y cable, though it sort of functions that way. I just tested the "AUX out" on my original A07 with a multimeter and also a subjective listening test. I measured a resistance of 1000 Ohms from the RCA center pins to the tip/sleeve of the 3.5mm AUX out. Identical resistance on both channels.

I just did the same procedure on one of my 3 1/2+-year-old spare A07s and got zero ohms with my Triplett 9045, the same reading as touching the probes together. If yours is newer -- mine has the 50 WVDC shunt capacitor and reversed L-R channels at the 3.5mm jack from back in those days -- your "1000 Ohms" may be the result of an Aiyima design change further on down the road.

 

[wave]

Chinese like to do that, change design without notice/revision change etc

 

[magreen]

I just did the same procedure on one of my 3 1/2+-year-old spare A07s and got zero ohms with my Triplett 9045, the same reading as touching the probes together. If yours is newer -- mine has the 50 WVDC shunt capacitor and reversed L-R channels at the 3.5mm jack from back in those days -- your "1000 Ohms" may be the result of an Aiyima design change further on down the road.

Fascinating. Yes, mine is new -- purchased in September 2024. Sounds like a design change.

 

[misfits73]

A couple of questions:
-Do the stickers on the boxes indicate any revisions/changes/improvements?I compared mine with a friend's and we see 22xx0019 and 23xx0009, look like date codes
-Does it have speaker protection in case it goes faulty?Haven't plugged my Proacs yet from my main rig
-Compared to the Fosi V1.0b (3116D2) is there a big difference in sound?
Thanks

 

[Bruce Morgen]

A couple of connections:
-Do the stickers on the boxes indicate any revisions/changes/improvements?I compared mine with a friend's and we see 22xx0019 and 23xx0009, look like date codes
-Does it have speaker protection in case it goes faulty?Haven't plugged my Proacs yet from my main rig
-Compared to the Fosi V1.0b (3116D2) is there a big difference in sound?
Thanks

I don't know about stickers, but I know there have been several revisions, e.g. the L+R channel reversal at the 3.5mm jack has been corrected and the main shunt capacitor is now rated at 63 WVDC instead of the early version's 50 WVDC part. To my (limited) knowledge, all "chip amps" rely on the output IC's built-in protection feature -- I'm not sure how protective of speakers that capability is, but I've yet to hear about any fried woofers being traced to a chip amp failure. I own both several A07s and an old 2.1 TPA3116 Dayton chip amp and the A07s are audibly superior -- so much so that I've demoted that Dayton to casual TV sound duties while retaining two of my now-elderly A07s in my main 7.1 system.

 

[misfits73]

The one with the bigger heatsink has 23xx0009 and 2200μF caps
The 22xx0019 has smaller heatsink and 1200μF caps.

I prefer the sound of the second one, unless it's down to the NE5532P on the newer version as i read a lot fakes float around

Very strange

 

[Roland68]

The one with the bigger heatsink has 23xx0009 and 2200μF caps
The 22xx0019 has smaller heatsink and 1200μF caps.

I prefer the sound of the second one, unless it's down to the NE5532P on the newer version as i read a lot fakes float around

Very strange

View attachment 417613View attachment 417614

Maybe not as strange as you think.
Did you do the comparison with really identical volume? Measure the voltage with a multimeter?
Could you really tell the difference between the two amplifiers blind?

You could swap the NE5532 in both amplifiers, then you'll know if that's the problem.

 

[misfits73]

Maybe not as strange as you think.
Did you do the comparison with really identical volume? Measure the voltage with a multimeter?
Could you really tell the difference between the two amplifiers blind?

You could swap the NE5532 in both amplifiers, then you'll know if that's the problem.

The one with the bigger heatsink does not have the full body the old one has neither the oomph in bass/midrange.
It justs sound louder and "lively" to the extend of causing fatigue, volume matched.

I'll try swapping the opamps

 

[Bruce Morgen]

The one from Amir's teardown thread -- note the 50 WVDC capacitors:

 

[JeffGB]

I just hooked up my old Aiyima A07 and am really enjoying it. I have several tpa3255/tpa3251 amps and I like the subjective sound of this one the most, even though the measurements tell me I shouldn't. I have an original Topping PA5, the Fosi V3 and the A07. Of the three, the Aiyima has the highest gain, the Topping the lowest gain and the Fosi is in between the other two for gain. While I appreciate the lower distortion of the PA5, it just doesn't have the same "wallop" in dynamics and neither does the Fosi. It's interesting that in the measurements, the Aiyima A07 has the lowest high frequency distortion at 6w and 15khz even though it has 10db more gain than the Topping and 5 more db than the Fosi. All the extra feedback doesn't seem to have much effect above the mid-frequencies.