I have been using the FX502Spro amplifier since 2019, paired with a Meanwell LRS-150-24 power supply. Throughout this time, the "error" LED indicating protection mode has never been activated.
In my setup, I utilize a Topping D30 DAC, FX-AUDIO Tube-01 Preamp/Buffer, and Pioneer SP-FS52 speakers. The buffer level is set to around 10 o'clock, which is close to unity gain. Even when playing guitar through another amp simultaneously, I rarely raise the amp volume beyond 12 or 2 o'clock, as it becomes excessively loud for my apartment.
Although I'm aware that adding a tube preamp introduces some noise, I did it because of the positive feedback in various online forums, and following that kind of esoteric approach, I decided to replace the opamps with LM4562NA/NOPB based on recommendations. However, after acquiring another unit and conducting a comparative recording of both opamps using the same amplifier, we concluded that there was no discernible difference in sound quality.
One notable aspect of this amplifier, in my opinion, is its excellent performance when it comes to reproducing female vocals, particularly in the absence of busy instrumental arrangements.
The only thing I can't stand is that the equipment turns on every time it's plugged into the power outlet, so it can stay on for days whenever there's a power outage or someone has manipulated the plug.
I'm really looking forward to seeing an upgraded version of the TPA 3250 with noticeable audible improvements. However, I've come across quite a few negative reviews about the Fosi Audio V3. At the same time, I'm not sure if those negative opinions about the lack of clean volume in both amplifiers really apply to their use at home with moderate volume levels.