I have a Mcintosh MC602 600 watt amp, and a C500T preamp plugged into a PS audio PPP. I was using AC-9's on all but the preamp. I tried replacing the amp power cable with an AC9 SE first. All I can say is that's all it took to get me back on the phone to replace the one on the PPP. I tried it on my C500T pre, and it brought more improvements compared to the Signal Audio Silver Resolution power cable.
The music just became more dynamic, clearer, and with deeper bass. It was a significant upgrade, and worth the price, in my opinion. I took up Audio Advisor on their upgrade plan where they give you half the retail price of the AC9 when you return it.
Finding a great power cable on the pre was most difficult. Most of what I tried (within similar prices) made the overall sound dull. The Signal Silver Resolution, despite being like an icepick in the ear on disc players and my dac, brought life to the music when used on the preamp. The AC9 SE further refines the sound (especially the bass) without making the sound dull. I'll still be revisiting the Signal when the AC9 SE has burned in adequately, but I think the Pangea will win out at this point.