So we have a problem. Below is the frequency response into JBL Control1 Pro, measured at amp terminals. There is a big interaction of the output filter with the speaker impedance and this may be audible. I think it is the peaking between 3kHz and 10kHz that might be audible. Great post! & great pics! Pop a temp gauge on your voltage regulators and see what they read. The community, I'm sure will benefit from and appreciate it. The temps of the regulators is the most important thing to observe. Because of what op-amps do... Those can heat up to much and fail. That's why I'm not going to be able to recommend the SparkosLabs for the A07 pro. Electrolytic capacitors used in electronic circuits are sensitive to ambient temperature and vulnerable to surges.

The AIYIMA A07 Pro’s brushed aluminium body feels well-built and sturdy and it has a reassuring heft to it. The volume and tone control knobs on the front are also aluminium and are nicely weighted. However, they’re not detented so you have to dial in the neutral position visually or by ear. This is normal. Therefore, I do not need a fan. I only need to vent the enclosure. And even this is just a preferential choice. Not a necessity nor a requirement. Also... It is important to note that it literally makes no sense what the Aiyima rep said about these op-amp positions.So again... I can vent the case, run fans, whatever.. The point is - we shouldn't have to do any of this.

In the position relationship between U3 and U8. The SparkosLabs are kind of tight. But appear to be fine. This is why monitoring the temps of the voltage regulators is important. If you are experiencing temps over 158°F or 70°C. Then you will need to be concerned. With the LM4580 the A07 sounds balanced, with a somewhat lighter bass presentation, but very neutral overall--a cheap and pleasant surprise.A brief history of TPA3255 amplifiers​The Aiyima A07 was the first "cheap" class D amplifier recognised by the audio community as "audiophile" quality yet at a nice price for those starting off in the hobby of home audio. It provided clean / neutral sound without the noise / "tinny" sound of previous class D amplifiers in the equivalent price range. It was praised by subjective "YouTube" audio reviewers like the CheapAudioMan yet also highly praised by objective reviewers from AudioScienceReview and others for its excellent SINAD / THD+N values (meaning it provided clean audio without distortion at high levels of output with a neutral accross bass, midrange and treble). There were other competitors in this market but Aiyima iterated over the design of the A07 with the A08 and a number of other class D amplifiers adding more features like bluetooth / tone controls etc to the basic TPA3255 design. The Aiyima published THD+N results for A07 MAX are slightly behind the V3 (0.003% for the V3 and 0.007% for the MAX) this translates into SINAD values of -90 for the V3 and -83 for the MAX. Note: these measurements have not been independently confirmed yet but they are inline with the expectation based on previous results. This is the frequency response into 10ohm. Note the 50kHz LC filter cut-off and also gain peaking at 45kHz because of lower damping of the output LC by 10ohm load.