For almost 2 years, I've owned the SH9, and I want to say that it's one of the most successful amplifiers from SMSL (with a perfect channel balance and remote control) in terms of price, quality, and convenience. Recently, I bought the Topping A30 PRO at half price. Overall, I liked it a lot; it's a very good amplifier with many connectors, a power switch, and well-thought-out design. However, it's a pity it doesn't have remote, and the volume control is not very convenient. It also gets quite hot despite the well-designed technical openings all around it. In this regard, SMSL has room for improvement. It would be good to have such openings on the sides at least. Because the SH9 also heats up. Two small 5V fans completely solve this problem and are inexpensive. On the A30 PRO, you can place them more easily from any side, even from below or the side. On the SH9, I installed two fans at the back, which blow into the XLR jacks. The airflow isn't as good as on the A30 PRO, but the fans do their job. I no longer feel the heat, and the chassis stays cool.
If we talk about the sound in general, it's difficult to notice any objective difference when switching between them because the volume levels are different. Subjectively, the A30 PRO has slightly more noticeable low frequencies, while the SH9 has a slightly more neutral sound. But these are all based on personal preferences. Both amplifiers are wonderful.
Initially, I planned to keep the newer A30 PRO out of these two, but I still prefer the SH9 based on my personal preferences. I don't need more power, but the perfect channel balance (256-step attenuator using a resistor ladder and remote control) provides incredible convenience compared to the A30 PRO. Furthermore, as mentioned in previous messages, SMSL has updated the firmware to version 1.0/1.11 in the latest revisions of the amplifier. Finally, SMSL heard our prayers and made the screen switchable off! (They should have done this with the first-generation M500; it would have been great, and it's not a problem to flash it). You can set time intervals for turning off the screen, and they added a few more brightness adjustment levels and some menu options.
In general, after 2 years, I still love my SH9, and I haven't regretted this successful purchase. Before this, I had the SP200, and if it had a remote and a similar attenuator, it would have been a wonderful small and powerful amplifier. Maybe these brief comparisons will be helpful to someone.
I apologize for the machine translation.