The best coupling caps in power amp ?? Mundorf, Infinicap ??

Duelund’s Cast-PIO-Cu caps ARE more resolving and open, than any that I’ve tried over the years. I don’t want to hear anything but the original music and venue, without any editorializing. Duelunds are just less, "there" and allow me to hear further into whatever’s on my recording. I’ve had four in my Cary SLM-100 monoblocks, for a few years. btw: Some say that foil orientation doesn’t matter with stacked caps. Testing for noise proves otherwise.

I too just replaced the coupling caps in my 300b Audion with the Jupiter Copper caps and the results were excellent. Very Surprising the improvement.

Rodman,
It's interesting to note that when proponents of the VCap describe its character the word is neutral. 
Duelund CAST proponents descriptive word is natural.  Both are meant to be complimentary yet they convey perceptive differences. Having used both capacitors I understand the chosen terms. Natural is the highest compliment I can use to describe an audio product. 
Charles 

I have built more tube amps that most people have seen.......I have used 20-30 different caps over the years......I have always been interested in the descriptions people give of there sound experience when dealing with different sounds , speakers and delivery of sounds.......I try and use this information in the construction and delivery of tube amplifiers.....I try to understand the descriptions people give for different sound quality in words that differ from one to another when describing the same sound ......When one person says "warm" and they are using a V-cap another may use a totally different word to describe their experience ......autospec

YEP, "variables"!    Semantics, perceptions, systems, aural acuities, references(if any), etc.   Of course, the better(to me, more neutral/transparent/clean/natural/quiet/fast) ANYTHING(tubes/rectifiers/caps/cables/special copper/silver) swapped into the total system, the more obvious strengths OR weaknesses upstream will become.   The natural tendency(for most) would be to attribute whatever perceived differences might be exposed, to the new component(s).       "Best" will always be subjective.