A few weeks ago, I wanted to purchase the Aiyima TPA3255 2.0 amp through eBay, but the seller in China could not ship the amp due to the COVID-19 virus outbreak. They were great about it and refunded my payment, that left me with the only option to purchase the Aiyima TPA3251 2.0 amp through Amazon.com who had some inventory of these amps in the US.
I connected this amp to my main system using my Audio Research LS7 tube line stage preamp and modified Klipsch Forte II speakers. This is where I started my critical music listening and discovered that the right and left channels are reversed, so I switched my right and left hand RCA interconnect connections. My reference power amplifiers are a rebuilt McIntosh MC240 vacuum tube amp and Pass DIY Sony VFET Class A solid state amp I built with the diyAudio.com store kit offered several years ago.
Both of my reference amps are excellent and I am quite pleased with the low distortion, highly musical performances of both amps in my system. I connected the Aiyima amp to the Audio Research preamp and my speakers, and I have to say this little amp is impressive. First of all, it is very quiet with no music playing through it. I held my ear close to my high sensitivity Klipsch speakers and heard no noise. As for the sound, it is not as good as my reference amps, but it wasn’t that far off either, which is astounding considering that this amp is only $50 USD. The fact that the channels are reversed is my only real complaint about this amp.
I have my volume on the Audio Research set in the normal position I use for most listening, and I have the volume pot on the Aiyima amp set to 2 to 2:30 o’clock with best results at my usual listening level. I am very impressed with the frequency response from the lower registers to the treble. This amp has a smooth, neutral frequency response and tone. What is surprising is the separation and detail I hear with this little amp. The soundstage is large, but could have more depth. I am satisfied with my purchase even with the mislabeled channel connections.
I have placed an order for the OPA1622 op amps on DIP8 adapters, and I will try those. If I hear a significant improvement, I might be tempted to try the NJR MUSES02 op amps.