Below are comments from Tony Gee of Humble
Homemade Hifi. Tony Gee is a loudspeaker designer and interior-architect from The Netherlands. He has been
designing loudspeakers since the early 1980's and has published several articles in Dutch audio magazines on DIY
The AmpOhm FP-CA-AU is a very neutral sounding capacitor that takes a nice smooth and
calm approach to the reproduction of music. I found the balance of the midrange very pleasing letting acoustic
instruments keep their natural warm tone. Absolute detail and air isn't quite up to the level of an Audyn Cap Plus
or Mundorf Supreme but it comes very close although they do need some time to open up so don't judge them fresh
out of the box. Spatiality is broad with reasonable depth but if you want "bowling alley" depth go for (the much
more expensive) Mundorf Silver/Oil. Compared to the more luxurious Amp Ohm capacitors they are more 2D and a
little rough, but again those cost far more.
The AmpOhm PF-XAL-AL 300VDC is very rich in harmonic textures and quite
spatious. When fresh out of the box they can be a bit "chesty" or "nasal" sounding but they mellow out after quite
some time of use (several hundred hours). Their tonal balance is very neutral and smooth, words like natural and
analogue come to mind. Imaging depth is very good but not quite at the same level as their paper-in-wax or
polyester-in-oil stable mates.
AmpOhm PF-XAL-AL 630VDC is basically the same type as the above mentioned capacitor but with a higher voltage
rating. The higher rating is obtained using thicker materials and therefore the 630VDC version (65mm) has a larger
diameter than the 300VDC version (45mm). Both have the same length (95mm). The 630VDC version reminds me of a can
of beer or coke. The higher VDC type is also very rich in harmonic textures and quite spatious. The tonal balance
is very neutral and seems a fraction smoother than the lower VDC type. Imaging depth is very good but like the
300VDC version, not quite at the same level as their paper-in-wax or polyester-in-oil stable mates. My review
notes also state: black background.
AmpOhm paper-in-wax aluminum foil type seems a fraction flatter or condensed sounding when in direct comparison to
the Ampohm paper-in-oil aluminum foil type. It is a little more direct in it's presentation compared to paper-in-
oil but more laid-back when compared to the polyester-in-oil types. I also noted less "fleshy" and a tad thinner
than the Ampohm PIO. There also seems to be a fraction more emphasis on the frequency extremes giving it a
miniscule loudness effect when compared to the very analogue midrange character of the polyester-in-wax type. This
is not meant in a negative way seeing the overall high quality sound level of this capacitor, as it's character
could prove usefull when fine-tuning a loudspeaker in a certain direction.
AmpOhm FE-XAL-AL 630VDC Polyester in Oil / Aluminum Foil
polyester-in-oil aluminum foil is overall very coherent and neutral. This type has a pleasant midrange-highlight
when in direct comparison to the Ampohm paper-in-wax aluminum foil type. The polyester-in-oil is very rich and
extremely good in retrieving ambient information such as room or hall acoustics. Music is presented in a natural
and full-bodied manner. Compared to the Duelund VSF-Cu copper-foil the image is more "see through". Compared to
the Mundorf Silver-Gold-Oil the presentation is richer, especially noticeable on massed strings or large vocal
works. On small jazz-trio's etc the Silver-Gold-Oil high-lights micro detail a little more but doesn't quite reach
the same level of overall coherence the polyester-in-oil does so well.