I recently made a change to my system that made a significant enough difference that I wanted to share it with the group .....

For the past several months, I have been listening to a pair of custom made (and one of a kind) Parker Audio Troll Magnus bookshelf speakers. The Magnus version employs an older model of the Heil Air Motion Transformer instead of the already superb ribbon driver found in the Troll Signature. These Heil drivers are no longer manufactured, but happily, the diaphragms are still available.
It is a very simple (but ingenious and tasty) speaker design. The 5 1/4" midbass driver runs full range with a single capacitor crossing the high frequency driver over well above the "normal" point. The effect is wonderful. The speakers are lightning fast, wonderfully detailed, yet smooth and throw a huge soundstage ..... totally disappearing with 99% of the music in my collection.

The speakers were originally outfitted with Hovland - MusicCaps, which sounded very good to my ears. However, per Parker Audio Dave's recommendation, I decided to empty my piggy bank and replace the caps with a set of Duelund VSF copper (virtual stacked foil) units.

Wowsers .....

The improvement was in the same ballpark as replacing the coupling caps with teflon V-Caps in the Decware Select amplifier. They are very open and revealing of detail, harmonically correct and transparent ..... with the ability to "sort out" and make space between the different voices and instruments in a recording. In addition, they have a wonderful sense of control, removing a small amount of "splash" in the top end that I had noticed with the MusicCaps. This is especially noticeable with some closely mic'ed female vocals .....
The caps are not cheap, but I can highly recommend them to music lovers who own a pair of revealing loudspeakers with simple crossovers. Duelund makes capacitors that are even more costly than these (the CAST version) ..... but I'm not sure that my heart (or my wallet) could survive a bigger improvement than I am hearing with the VSF version .....

Enjoy the music,
Randy