Dan

it is a slippery subject and I do not think that anything could be “right” or “wrong” in there.  I generally do not “voice” drivers with section of capacitors. However, but it is not mean that I do not see difference between the capacitors sound. Juts as I said before any good caps inflict only “static” coloration that is not really important. Bad caps do “dynamic coloration” it is bad but we do not use bad caps, do we?

I can tall only about my personal experience and I did in the past combine oil and film. As many others I have a very large box with speakers-type-value capacitors the box has all imaginable caps, staring from exotic Teflon and cupper foils and ending with many hundreds uF polypropylenes or huge and expensive cupper Jensons…

My personal observations I my surmise in following:

1) For larger values 10uF and up the electrolytic with active bias do the best. Among many caps the I tried in this application the Nichikon was preferable (not even Muse but the cheapest KZ line)

2) For smaller values I like Sprague Vitamin Q from 50s. They are available 1uF and you can pile them up as much as you wish. Vitamin sounds horrible for the first 5-6 days: no HF, very noise and very dirty. Then it clean itself up

I tend do not bypass or mix the caps, thought I admit that the Vitamins are at a very slight soft side…It kind of never heard to save a lightly soft cap where the S2 sitting somewhere down the line…

Yes, it is a common deal and it is possible very frequently to get a bunch of the Vitamins Q for very little money. Thanks God that no one from Sprague pay (paid) to market-makers to drool about the Vitamins’s sound and therefore the wide majority of Morons do not know about the Vitamins Q’s sound. Also, what keeps the Vitamins Q in shadow is the fact that they sound extremely horrible for a first 5-6 days…

There are two type of low voltage Vitamins: withy chasses connected and chasses lifted. I prefer the chasses (the body of the cap lifted). Also the 1uF Vitamins are not 1uF but very slightly less. If you put 8 of them together then you will not have 8uF but more likely somewhere like 7.5uF. Have a few small values Vitamins ready to parallel them with the rest bundle in order to get the exact value you need.

Another very interesting idiosyncrasy of the Vitamins is that they most likely love current. The Vitamins do very fine in speaker-level crossover but when they use in line–level as coupling caps then do not do well. Listen many Shindo units and you will hear what I mean.

Also you will see some sealers advertise this caps as “Vitamins Q” but they are not the Vitamins Q. They have a very similar contrition and identical “vintage” look but they have no letter “Q” on them. There were a number of companies that did them (I have a many of them) but those caps have no Sprague “Vitamins Q” impregnation. Therefore always ask for a picture of the caps you buy or a conformation that it has the “Q” written on them. I anticipate that if the Vitamins’ popularity will go up then we will see some counterfeited caps with Vitamins Q making….