B&W recommends use of an amp with a minimum rating of 25 watts. I think the SX-525 is rated at 15 watts.
It will certainly drive them, but once you go beyond moderate listening levels, the amp will run out of power and start clipping the signal. Heavy clipping can lead to damage of both the amp and the speakers, as well as causing very audible distortion. If an average loudness around 83dB (approximately), about 8 feet from the speakers, meets your needs, the SX-525 may suffice.
To get an idea of how loud that is, you can download a free decibel meter for your smartphone and use it to measure loudness of your current system (focus on average level, not peaks). See if 83dB (measured at 8 feet from the speakers) is enough for you.
The problem is that those speakers have an unusually low sensitivity rating (84dB). The lower the sensitivity, the more power it takes to achieve a given loudness. Most modern speakers, especially smaller ones, also have relatively low sensitivity ratings, but more in the 86-88dB range. Compared to a speaker rated at 87dB, the B&W's need twice as much power to achieve the same loudness.
Bottom line, if you have a small room and listen only at very moderate volumes, they should be ok for you. But they are nowhere close to an ideal match.
