Puritan vs Nordost Power Cable

I recently exchanged a Nordost QB4 power distributor with a Nordost Valhalla power cable for a Puritan 156 with the Puritan (upgraded) "Ultimate" power cable.  I noticed a significant improvement in the overall sound of my system with more detail, articulation, clearer bass and a deeper soundstage.  

I decided to experiment with the power cable feeding the Puritan 156, to determine the effect of the power cable feeding the Puritan 156 (i.e. comparing the Puritan ultimate power cord vs the Nordost Valhalla).  This was most educational as I could (finally) appreciate the differences many professional reviewers note in their assessments.  Before describing what I heard, let me describe my system as I am sure the differences are at least partially system dependent.

Rogue Audio Stereo 100 am upgraded to their "Dark" specifications.
Rogue Audio RP-7 preamp with Telefunken tubes and connected by balanced XLR to the amp
Chord Dave amp with Nordost Valhalla RCA connection to preamp.  Cardas Beyond USB cable from MacPro.
AMG Vello turntable. Valhalla cable to preamp
Soundsmith Strain Gauge (with its own "phone amp", SG200) with their SG-6 stylus.
Nordost Valhalla speaker cables 
Sonus Faber Amati tradition speakers
dedicated 20 amp circuit with hospital grade outlet

Music used for evaluation:
Issac Perlman Vivaldi 4 seasons (spring)  (Angel recording)
Night on Bald Mountain (Power of the Orchestra RCA Living Stereo)
Variety of jazz and orchestral pieces ripped from CD or higher resolution downloads all played thru Audirvana.

Disclosure:  I accept that there are those that deny that cables can make a difference in the sound.  In MY system, with MY power, and the limitations of my own hearing (ears), I hear a difference.  I can only speak to what I hear.

Nordost Valhalla power cable:
There is less detail, for example, in rapid bowing or the way the musician "pulls" the bow across the strings , or where the musician strikes a tympani or drum or how the musician "plucks/bows" the double bass or the violin. There is certainly a difference in the way Perlman plays Vivaldi and others I have heard!   This cable is not as "fast" or articulate.  It is as if the "sustain" pedal  on a piano has been held down.  Notes tend to run into each other vs more separation.  Staccato passages are not as distinct, separated, dramatic. This decreases the clarify of say a fast drum solo in a jazz piece, or the attack of a snare drum. The bass seems "fuller" but this seems to reflect again an extension of each note and perhaps some "blurring" of the sound which is especially noticeable in jazz.  The sound stage seems slightly less deep with more compaction of the instruments/musicians.  The sound is "warmer" and the overall impression is that there is a "fuller" more "coherent" sound, a circle colored in uniformly, smoothly.

Puritan "Ultimate" power cable:
Clearly more articulate, faster and more detailed.  Every note is distinct even in rapid passages.  There is space between notes and musicians such that if four trumpets are playing a chord, you can hear the chord but definitely each note in the chord.  There is a "snap" to a snare drum, and the resonance of a tympani or a double bass is more distinctly appreciated.  The musician's technique or interpretation of the music is more obvious;  the way the jazz bassist "plugs" the strings, or the way Perlman applies difference pressure to the bow and the sheer rapidity of his "runs" and passages.  The space between instruments and musicians also allows complex (orchestral) passages to be better appreciated as the individual components are readily heard along with the overall sound. Indeed, I heard for the first time certain instruments usually lost in the "blend".  This leads to a deeper appreciation of the composition.  The sound stage is perhaps slightly wider, but clearly deeper.  The increased articulation and detail, the greater separation of the instruments does lend the impression that the sound is less "full".  The circle is filled, but with (innumerable) dots rather than blended, smoothed, brush strokes ("pointillism" vs "water color").  This also tends to make this cable sound perhaps what the reviewers call "cooler" than the "warmer" Nordost.  This may also render this cable  slightly "brighter" on treble but not harsh and this is very dependent on the recording.

Hope this helps.