Audio upgrade is a never ending journey. It all depends upon where you want to stop and get off, and whether the point of diminishing return is worth the price to you. Just like in wine, how much you are willing to pay for a bottle of fine wine depends on how much you enjoy that extra bit of aroma. Similarly, you can always get more improvement in the sound through an upgrade in something, whether a new cable, power conditioner, speakers, amp, preamp, etc.
Point here is that both the power conditioner and power cords make big differences in sound. So both are just as important. Even more amazing is that the power cord that connects the power cord to the conditioner and the wall socket is also extremely important. It sounds sort of counter intiuitive....
However, given that you have not upgraded your power cords or purchased a power conditioner, I would suggest that you start with power cords. Because once you start with a power conditioner, you already clearly have the audiophile disease because normal people don't feel the need to regenerate or condition the electricity in their home....
