AIYIMA A07 Premium TPA3255 Power Amplifier 300Wx2 HiFi Class D Audio Amp Mini 2 Channel Stereo Amplifier for Passive Speaker Desktop Bookshelf Home Theater System with DC 32V Power Adapter

This is an amplifier that punches way above its price range and size. It is well built and looks great. It has tested very well for its technical performance (see Audiosciencereview's test report) and that is reflected in its sound performance. I am using it to drive Elac 6.2 Debuts, and it has plenty of headroom that I will never need. And I am using the 32V 5A power supply option, which means I am barely powering it to just over half of the amplifier's output potential.The amp runs very cool when driving my Elac 6.2s. I am using a Schiit Modi 3+/Magni 3+ stack to feed the amp.To take the sound to the "next level", I tried several op amps including one that was recommended by an engineer at Aiyima in a paper called "The OP Chip Can Use on AIYIMA A04 & A07". Obviously I tried the NE5532 that comes with it. This sounds great as it is. I tried the LM4562NA. This offered some improvement. I did not leave this one in long enough to characterize it, only that the sound was "better". I tried the OPA1656, which I feel actually degraded the performance. The op amp that made a significant improvement is the OP275GPZ. This is one that is recommended by the manufacturer as an op amp that offers "Better resolution, low frequency and sound field than NE5532". I found this to be very much true. I think by "sound field" they mean "sound stage" as that really did open up. There is a clear improvement in resolution. I also found the treble to be more refined which was not expected from the description from Aiyima. And it also took "boxiness" out of the vocals. I don't know if the boxiness originated from the amp or my speakers, but the 275 cleaned up the vocals and they are now simply excellent. If op amps were free, I would try some others that the paper recommends. But given that they are not, and I feel I have hit on one that yields a big improvement, I am done searching. Any others will either most likely be a step back or just offer marginal additional improvement.This is a great amp as it ships. Since the input stage op amps are socketed, you have the opportunity to "roll" them to adjust the sound to your liking as I described above. For me, I found the 275 to be a phenomenal choice.Based on my experience, I highly recommend this amp!

I'm a retired radio engineer, but I still do a fair bit of recording - live concerts, choral groups, voice over, some program production. I've wanted something decent for listening to recordings in an unused room at home. Not a lot of room available... I had a small amp that I bought from a supplier in Ohio, tried that, and didn't like the sound. It simply couldn't handle the transients at a moderately high level without breaking up. I can't afford the high end stuff...So I went looking and found this amp. Reading Bob P.'s review, I decided to take a chance. I'm glad that I did. The sound was significantly better than the previous amp, clearer, but not quite what I was looking for. I tried three pairs of speakers before I decided to use a pair of KEF C35 speakers. While the sound was good, it was just a little "off." "Boxy" was a good description. So I decided to do the suggest upgrade to the O275GPZ op amp chips, and ordered from a vendor here on Amazon. The cost was $26 and change for two Analog Devices chips (I avoid off brand chips) , but it made a world of difference. Well worth the extra money.The amp is easy to open (2.5mm hex key), and as noted the chips are socketed so easy to swap out. I was pleased to see that they are high-reliability sockets, not cheap ones.Files played through a 4th Generation Focusrite 2i2. Not Benchmark grade, but clean.

Yes, there is a difference between peak and average power. Audio is not a continuous load. It's important to be able to support the peaks. The performance is well documented for various power supplies and loads. Average power is largely a thermal issue. Class D amps are dramatically more efficient, but there is a limit to how much heat a compact package can dissipate This is probably about as much clean power as can be obtained in this size without external heat fins or active cooling.Internal components are great. The control knob is nice and firm. They did not skimp on the inductors.I did have an issue with the unit being slow and irregular when turning on. Things happen. Intermittent problems are hard to catch and can easily get by QC. Customer service responded in less than a day and was great.Very happy. I also bought a BT version and will get more of this brand if the need arises.Simple, clean, quiet performance!