fdd5d689_e_Notes_on_Coupling_Capacitors__Impressions_HV
[Brand] Sprague Vitamin Q 0.47uF 300V (96P47403S2) ~$4.00 [Impressions LV] . [Rating] 3½ [Impressions HV] 
In the past, I have not evaluated Vitamin Q's on their own because they are hard to find in high enough values and high enough voltages. But, I retooled my testing rig to increase the input impedance of the amplifier to about 100K which means I can get away with a 470nF cap as a coupler and still have a decent 3db point. So, it was time to try the VitQ's. If you read a lot of internet forums, the reputation for these caps is that they are soft and gentle, maybe rolled off a bit, and overly lush. Interestingly, this is not only almost exactly wrong, but it describes a lot of the polypropylene caps pretty well. Instead, Vitamin Q's, which are paper in oil, are extremely clean and clear, and have a sort of sparkle to the top end. If they have a fault, it is that they do not exagerate the bass, and maybe miss some resolution compared to the very best caps. But, really, this is a maybe. These are really good, really musical, caps. They are not bloomy in the mids at all, which actually allows things like female vocals to sound strong and incisive, not like they are in the Star Trek soft focus of an Auricap. Obviously, these are not going to be everybody's cup of tea, but I find I can get lost in the music more easily with these as my couplers than just about anything else. Highly recommended.
ecp audio diy: Some Notes on Coupling Capacitors
Impressions HV