This is a teardown of the AIYIMA A07 TPA3255 Class D Amplifier I just reviewed. I gave it high marks for very low distortion at extremely low budget price. Question was raised on the revision of the board and thermal characteristics of the unit so here we are.
I was very pleased to see the PCB having silk screen markings for all surface mount parts:
The business end, i.e. TI TPA3255 IC is buried under that gold color heatsink. To the left we have some power supply circuits and input buffers made up of common NE5532 opamps. To the right we have reservoir capacitors and output filtering. Speaking of those caps, I was very surprised to see them having the top capacitor brand, Nichicon:
Someone should do the forensics and tell us if they are the real deal or fakes.
Soldering job on speaker terminals and such is acceptable.
The back side shows smudges and imprints of other boards:
They could have cleaned it but at these prices is not something you expect. It should work fine.
I let the amp run for about 6 minutes driving 20 watts x 2 into 4 ohm load. The heatsink was too hot to touch and temp kept climbing:
TI specs the chip at 90% efficiency at max power. At 20 watts, it is running around 80% efficient so is producing 8 watts of heat into that little heatsink. With no vent or circulation, I would not deploy this amp for continuous high power use. The junction temp is rated quite high at 150 degrees C though so it is a tough little chip to kill. It has a thermal shutdown of 155 degree C so if it does that, you best not push it remotely that hard.
The two aforementioned electrolytic caps are sitting pretty close to that heatsink. If they not nichicons, they may go first.
Conclusions
Sans the pedigree of the caps, I really don't see corners being cut here given the target market and very low cost of the unit. It could have been much worse than it is. With power supply being external, safety risks lay there, not inside this amp. The metal enclosure should contain any fires and such in that unlikely event.
So not bad!
------------
As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
I was very pleased to see the PCB having silk screen markings for all surface mount parts:
The business end, i.e. TI TPA3255 IC is buried under that gold color heatsink. To the left we have some power supply circuits and input buffers made up of common NE5532 opamps. To the right we have reservoir capacitors and output filtering. Speaking of those caps, I was very surprised to see them having the top capacitor brand, Nichicon:
Someone should do the forensics and tell us if they are the real deal or fakes.
Soldering job on speaker terminals and such is acceptable.
The back side shows smudges and imprints of other boards:
They could have cleaned it but at these prices is not something you expect. It should work fine.
I let the amp run for about 6 minutes driving 20 watts x 2 into 4 ohm load. The heatsink was too hot to touch and temp kept climbing:
TI specs the chip at 90% efficiency at max power. At 20 watts, it is running around 80% efficient so is producing 8 watts of heat into that little heatsink. With no vent or circulation, I would not deploy this amp for continuous high power use. The junction temp is rated quite high at 150 degrees C though so it is a tough little chip to kill. It has a thermal shutdown of 155 degree C so if it does that, you best not push it remotely that hard.
The two aforementioned electrolytic caps are sitting pretty close to that heatsink. If they not nichicons, they may go first.
Conclusions
Sans the pedigree of the caps, I really don't see corners being cut here given the target market and very low cost of the unit. It could have been much worse than it is. With power supply being external, safety risks lay there, not inside this amp. The metal enclosure should contain any fires and such in that unlikely event.
So not bad!
------------
As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
This one had very nice, threaded hex screws and was very easy to open and put back together.
