I bought a A07 without the LM4562 OP chip. Where can I buy the LM4562 OP chip only ?
Please don't be offended here... that is not my intention ...
But I get the general impression you have little or no actual technical skill in electronics.
Now this isn't a bad thing, until you pull out the screwdrivers and start poking round in the guts of something.
If you've never done this kind of setup before ... chip flipping, supply bolstering and bi-amping probably isn't a job you should tackle without qualified help. Many things can go wrong, some of which will involve fire extinguishers.
One of the risks of getting into a highly tech-savvy place like this one is that there are a whole bunch of "gong bangers" waiting in the wings to make all nature of suggestions --usually their own pet favourite things they've never done themselves-- and if you aren't careful you can get all wrapped up in the "this is better than that"... and end up with a much improved but non-functional system.
If you already have the amplifier and speakers ... just hook them up the normal way and see what it all sounds like. Listen to it for a couple of weeks
as it is intended to be used before you get crazy with all these bright bulb ideas.
Industrial supplies require you to correctly connect AC wiring and DC cables. If you've never done this before, you could be in for a really nasty shock or two ... literally.
Bi-amping
correctly requires an external crossover network before the amplifier. This isn't a couple of resistors... it is a separate piece of powered electronics that you will need to learn how to program and setup. It also requires you to remove the existing crossovers from your speakers and rewire them.
Supply Bolstering means adding new filters into the power supply rails. Since there is no room in the SMPS casing and no room in the Aiyima casing for this, it means constructing an external device from scratch, to hold the extra parts. Hint: capacitors tend to explode of you don't get this right.
Chip Flipping means replacing chips inside the amplifier. In the Aiyima they are in sockets, but this is not something you can take regular tools to. It is very easy to damage the sockets or the chips and that will leave you with a dead amplifier. I don't care how easy that idiot Randy made it look in his video... it is a delicate operation requiring specialized tools to complete properly. He was lucky and nothing more. On top of that, if your amplifier is working correctly, flipping chips won't make the first bit of difference to the sound.
Okay... this got longer than I planned ... but please take some advice from a long time technician... just hook the thing up and enjoy it while you study up and learn how to do these things. You'll be glad you did.