The ESP essence greatly improves my CAT Ultimate in More solid bass, more inner details. Recently, I upgraded to the Shunyata King Cobra. It takes the improvement made by the ESP up even further. Give it a try.
The stock powercord works best, period. i really doubt if Ken Stevens has recommended the ESP cord, because what i gathered from many fellow CAT owners, is that Ken recommends using the stock cord. I also hear that the PSaudio 300 works great with the CAT, i tried some other AC filters with no good results, and some of these filters cost enough... happy CAT mk3 owner.
I have found the CAT Ultimate to be pretty much immune to the several power cords I have tried on it. I have tried the ESP Essence based on the recommendations of others and this thread. I was disappointed with the results as I didn't notice a great deal of difference. Then, I tried the Essence on my Pass Aleph 4 power amp. The bass was heavier, but not deeper. Overall, it was not an improvement. I went back to the stock power cord on the CAT and continue to use the Audioquest AC-12 on the Pass Amp, vowing to not waste any more money on aftermarket power cords.
I have the Ultimade version. I am currently using the ESP essence with excellent result. The bass is even more solid, more details and quieter background. The difference is not subtle at all. Give it a try. This power cord is actually recommended by Ken Stevens for the CAT Preamp.
I have a CAT SL-1 III with phono, and at first I was using a homemade power cord that I liked better than Classe and Cardas power cords I've had before. (I've sold some of mine to audio professionals--they're not too bad.) But the Stealth HAC power cord I have now is worlds better. In the first 10 seconds, I thought it was adding an edge to an instrument's sound. I quickly realized that the edge was in the recording, which I was simply hearing more clearly. See this cord at www.interlinkhouse.com, click on "Products". I All Stealth cables come with a 30-day money-back guarantee. I hope you don't pay more than you hve to for a lesser cord.
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