Neutral to Lean Power Cord for tube preamp

You most certainly can achieve your goal via pc. I would look at whatever the highest Nordost cable you can find in your range. Those have exactly the flavor you described as the goal. GL!

One thing not yet mentioned that would make a huge difference is how well your components are isolated. Ceraballs, stillpoints etc can likely make more of a difference than the power cord. Improvements in this area will tighten the bass and give you more detail.

Contact DCCA he can custom build you a cord that can do what you need. I believe that there is something wrong somewhere in your system that you will need to address. I believe that a power cord should not change the character of the sound just make it better. I have used DCCA power cords in the past to tune my system but now I have a different philosophy. I now put more emphasis on the equipment then the cabling. I found my self spending less on the equipment and more on the cabling in total spending more than if I would bought the right equipment in the first place. I do not by cheap cabling but good quality/value. I learned this from legendary people in the industry that when I went to their homes and I was shocked at how good their systems sounded and what they were not using for cabling. Just a side not for cheap you should buy several of the big spike kits from Parts Express and put some your equipment on the spikes. It's a cheap tweak and it tightens up the bass and it opens up the top end.

Before you spend a dime, optimize your speaker posistion first. This will have a greater affect on the tonal balance than any pc cord.

Agree with Brf move the speakers away from the front and possibly the side walls to balance/reduce the Ultra Verde's bigger bass. If that doesn't "tighten up" the bass enough for your taste do what Dmailer suggested for the last bit of detail before going to room treatments.