[Cross-posted, expanded post based on my original comment at Amir's YouTube video about this review - and from the original Aiyima A07 thread as well]
Hidden gem, indeed!
[edit] I noticed that three pictures of this amplifier in the original Aiyima A07 thread show different sizes of heat sink, with the original unit that Amir tested being the smallest.
I don't own the Aiyima A07, but early last year I purchased their lower-power A04 amp (TPA3251) for a "portable" system that I use with a 12v Talentcell 38400mAh Li-ion battery pack. I purchased both from Amazon last year. Before the pandemic hit, I took my "portable" system with a (DAP, amp, tiny Yamaha speakers and battery pack) to the weekly local (Boquete, Chiriqui, Panama) food, arts and crafts market where I used to sell my artisan woodturnings.
The quality and performance of the Aiyima A04 is very good, and would expect the more powerful A07 to probably equal the performance of my Ghent/ICEPower 70w amplification in my main system.
The Aiyima A07 was not currently found via my search at Amazon, but the
AiyimaAudio store (80 sold, 726 available) on AliExpress has it for USD $50.62 with free shipping to the US from China, or from a German location to Germany for free.
The A07 is also available for the same price from the AliExpress
AiyimaTechnology store (270 sold, 2942 available), which ships from China or Russia. This store also offers a choice of two different op-amps
The photos at both stores show the original, smaller gold heatsink. Which version they are selling? Hard to say, although none of the versions seem to have issues. Like many inexpensive "ChiFi" audio electronics, Aiyima appears to make component changes and use different component suppliers without notification or designation.