Neutral to Lean Power Cord for tube preamp

I recently added a deHavilland UltraVerve preamp to my system. It is quite powerful and dynamic, but has a little too much bass emphasis through my Von Schweikert speakers, driven by a McCormack DNA-1. All cables are silver, using a VooDoo power cord now on the preamp. Everything plugs into a PS Audio Quintet on a dedicated line. Looking for a very neutral, or slightly lean more detailed power cord, price range is up to $400 used. I am still tube rolling, so bass may get tamed a bit more yet.
I'd think using a different type of 6SN7 tube would be a far better way of addressing bass emphasis than AC cords.
The ideal bass tightening, detail allowing sort of A/C device is a power conditioner. Almost any actual power conditioner does exactly what you want: tigher bass, slightly leaner sound with greater detail and accuracy all around.
So keep the cord you have and find a small PS Audio P300 used would be my suggestion.
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.
I would not expect the tonal effects of a power cord, if any, to be consistent or predictable from system to system. Especially when used on a preamp, which draws an essentially constant amount of current, and generates little if any rfi.

I would pursue a different approach, of which there are obviously many possibilities.

-- Al
I do agree with the posts above although a used Nordost Vishnu or Brahma would likely move you that direction.
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.
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.
Like herding cats.....
ESP Essence Reference does exactly that but in a good way. It tightens up the bass (chopping off fats ?) and also makes the bass very tuneful and rhythmic. In the process it does amazing PRAT with a very clean, articulate background/soundstage. I think you will love it. It has the same effects on every component of the chain.

I will not recommend this power cord for already neutral systems (all solid state) as it can make the sound bit too tight. Otherwise it is one fantastic PC.
You can also get a similar impact by putting your preamp under Symposium Rollerblocks. The rollerblocks are wonderful for tube equipments. The ESP will have a more profound impact though.
I own an ultraverve and would suggest the VH Audio Flavor 2 for a good synergistic power cord. I have tried lot of cords with the Ultraverve and keep coming back to the Flavor 2. Also be aware that lots of gold ended cords can cause too much warmth in the bass in your system. So be sure to check your other cables and if they are all gold try brass.

Also the other suggestions about resonance control should be investigated as well. Good luck.
Tube540, Now you should be set!
Better 6sn7
Power conditioner
Nordost PC
Ultraverve PC
move speakers
get some cats
After all that, a week at the local Psychiatric Resort. You'll be good:)