We could go on about the P18 for days, but maybe you'd rather hear it from someone else:

"Ultimately, I can say that for some situations the Yulong Sabre P18 is a significant and worthwhile sonic upgrade. Just not consistently in all cases. But what is constant is the substantial protection from surges and other hazards, and the lack of any downside - even when it doesn't help the sound, I've never noticed a hindrance either. Which is actually kind of a big deal. When you consider the price and the size which seems ideal for headphone users, the Yulong P18 is very easy to recommend. If you have a decent system and have yet to invest in some type of power protection, you should look into it sooner rather than later, and the P18 could be just the thing." -project86's review on Head-Fi.