Review on AIMPIRE AD10 Mini USB DAC CSS XMOS XU208 ES9018K2M OPA2134 HIFI Audio Decoder Amplifier For Enhanced Audio Performance by Everette Jean

I purchased the DAC AD10 from Ampire knowing that it was a bad clone of Topping D10.After measuring the specs it showed really high noise floor level, around 15dB higher than the original D10.It was a clear indication that there was something wrong, most probably not well filtered supply voltage.I disassembled the DAC and found out that all chips looked fine but the aluminum electrolytic capacitors they used were not good, at least not suitable for that implementation. Just changing two of them, the noise dropped by 3-4dB. Changing all other did not make much difference.The next thing that I tried made a real difference - improving the output buffer.I tried as many different op amps as I had - maybe 12 or 13.Some were worse some were better. The best results I got with OPA1612.In that case the noise floor dropped more than 15dB! So I got the same value as the original D10, even a few decibels better. It was a strange finding because doing the same thing to the original D10 didn't show any improvement.The long story short - replacing the capacitors is not easy (it requires desoldering and soldering) and it gains just 3-4 decibels, but rolling the op amp with OPA1612 makes AD10 the same as D10. Replacing both the capacitors and op amp makes AD10 better than D10 (lower noise and THD but 1dB lower output level). The listening test didn't show any difference though.