Joined in 2023 
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The amplifier switched off itself after about 1 minute of this test, due to overheating. However it has survived. 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. I do agree that a bass control can't really remove a boomy sloppy bass quality, just make it less evident and the best thing really is to try to fix the boom either in the speaker or more likely these days, the room. This is a mini-review of the A07 MAX from my "average Joe" perspective. Aiyima was gracious enough to send me a unit for review and evaluation. I found the amplifier to be a lot like the Fosi V3 - apart from the noted Stereo/Mono feature, which I have not made use of.
The MAX volume is nicer than previous Aiyima Amps but linear on the V3 really nice and it is very subtle with lower volumes Pertanto, è noto da tempo che i progettisti di circuiti utilizzano condensatori elettrolitici con una tensione pari o inferiore al 70% della tensione nominale. Offering advice without it being asked for, is for the most part considered offensive because it can be viewed that the advice giver thinks that the person he is advising is too stupid to know better. This is why you don't give advice unless it is asked for. Advice, when not asked for is discouraged because it is discourteous and rudeA more internally-focused sibling to the alpha male. While the alpha male quantifies himself on his high position in the social hierarchy, a sigma male prefers to forego the social hierarchy and need for external validation altogether and pursue internal strength instead. Essentially a "loner" or a stray man, although sigma males may have a close circle of friends and loved ones with whom they share a deep connection. The sigma male is not socially inept but simply socially disinterested. Prefers solitary activities where he doesn't have to play social politics and can simply focus on himself. The sigma male accepts that he does not need power over others as the alpha male desires, but rather needs only power to control himself and preserve his own autonomy from others. I find it interesting that there is no negative leads attached to the speaker binding posts. Not that I can see. See the pics. When measuring A07, one has to bear in mind that it is a BTL (bridged) amplifier, thus both speaker output terminals are “Live”. There is always a DC voltage of ½ PSU voltage at each terminal. The speaker sees the voltage difference, so no problem, but SE input soundcard could not be used for measurements, as it would short one of the output terminals to ground. Please also note that in case of grounded 48Vdc power supply, each of the A07 output terminals would be at hard 24Vdc vs. ground. This will also happen with class II power supply but some of the audio chain components in class I, thus grounded.
Secondly, you cannot find any audio references in regards to single turn differential... You get automotive information. You're heading somewhere toward 500-600 hours or more of listening here with 20 songs at 3min. each.. And that doesn't even count the amount of time and effort to narrow it all down to favorites. I totally agree that the Bluetooth side of things with the A07 Pro is phenomenal sounding. No need for op-amp swapping at all actually. I was really impressed. Therefore, it has long been known that circuit designers use electrolytic capacitors with a voltage equal to or less than 70% of the rated voltage. Love this... Thank you. To note for the community, the Fosi V3 also copied over the A07's original design flaws... Users including myself have reported that the unit has channel cross-feed.
If we only had 10 different op-amps to choose from and we use the same op-amp in the U8 & U9 positions. That would be 210 different combinations. If we just addded 2 more op-amps to test... That number jumps to 495 combinations to try... Yikes! Maximum power: 200W+200W (the maximum power is AC220V in the power supply, 4Ω speaker, distortion 10%) In discussing this with others, they agree that the Aiyima rep either is steeped in a language barrier issue. Or they just don't know enough to convey accurately.
Realize this.. I'm spearheading this endeavor alongside an electronics engineer who is well suited to the task. Doing this with the intention to save you all a load headaches in the future. You were all advised that I was working closely with the designer of the SparkosLabs op-amps. I am doing the work here so others can make an informed decision and avoid pitfalls. I am not here seeking advice, accolades, affirmation or validation. If any of you wanted to collaborate and work together, the door was always open. I am advising and guiding you through these processes and informing you. Let's try to remember this going forward.However my latest A07, direct from Aiyima had 50v but the uf was a bit higher. I have seen ranges of 1000uf to 1200uf in this unit. Those 4 little nichicon 25v 10uf muse caps are an end-of-life product as far as my research has determined, so at some point these will be no longer available. Just a heads up on that one
You didn't put a smiley face... You put a wink. These emoji's all have certain connotations and implications when used. They are all dependant on circumstances and sentiment. In my listening space the Aiyima will play at levels that are truly painful, and that's with the volume knob set at about 50%. From the ASR review I know that there is a known issue with the amp (or power supply) shutting down at around 77 watts. Even at the 77W output level the measured distortion (ASR review) is quite low. Because I'm not experiencing the shutdown, I am confident that at the 50% volume knob setting, the amp is not even driving 77W... A more capable power supply is supposed to get this amp to higher power outputs without shutting down. With the 30V regulated PSU, we get very good suppression of mains components and the SINAD of 84.3 dB. As we can see from noise measurement, this is mainly affected by the residual noise. This is why some have found great results with a Sparkos in the volume stage and the Burson in the output gain stage. These do similar things, but the end results are that they sound different from each other and those difference are noticeable. Put them together though and you can get the best of both worlds... But only in that configurationkfor certain devices) . Swapping the Burson to the volume stage and the SparkoS to the gain stage doesn't give the same results. EL2244: The timbre is neutral, the sound field is relatively wide, the high frequency is okay, and the mid-frequency music tastes poor. Some people say that the resolution is very high. In fact, it is because the low-frequency volume is less, the mid-frequency is thin, and the high-frequency is prominent. It is more difficult to use well.
A brief history of TPA3255 amplifiers
Electrolytic capacitors used in electronic circuits are sensitive to ambient temperature and vulnerable to surges. However, one must consider this undertaking and take it seriously. Requiring the proper tools, skill and environment to safely modify the case so it doesn't look ridiculously hideous and doesn't cause health concerns from the aluminum waste that will be produced. The main cause of this is that the "pre-out" of the V3 and the "aux 3.5" of the A07 are just pass-through connections. Basically a Y cable. They are not true pre-outs or even an aux. This also makes it possible to use either the RCA or the 3.5mm for input. Obviously not at the same time though. I love having the additional line out for my subwoofer but because it is a fixed-level output, I need to adjust the volume of my sub each time I change the volume on the amplifier. Still, I’m glad it’s there because makes my system sound even better.
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