Does removing the plastic covers on caps help?

The comment above assumes that the plastic around an electrolytic capacitor is an integral part of the design and is used to damp vibrations. Given that 99% of capacitors found in high-end equipment are also used in computers, calculators, VCR's, etc, where "good sound" is not an issue, I really doubt this is true. Besides, how much engineering do you think goes into a run-of-the-mill $.15 capacitor?

The way I see it, the plastic shrink wrap serves two purposes, one, to act as a "billboard" to display the type and size of the capacitor and a clear way to deliniate the negative lead, and two, as an insulator to reduce the possibility of other leads in the circuit shorting against the aluminum can.

I have removed the plastic from capacitors in the PS of both amp and pre, as well as all plastic from the digital caps in my CD sources, and feel it is a worthwhile tweak. I attribute the increase in bloom and resolution a product of eliminating both the dielectric effect and a potential source of static charge (plastic).

For what its worth, all the capacitors in 47 Lab gear are "naked".

I agree with some of the points that you bring up Mbhcid. The plastic covering is more of an afterthought by most manufacturers to say the least and is primarily used as an insulator and as a means of identification. Having said that, that does not mean that it can't have benefits or drawbacks that may not have been originally taken into consideration. As such, i don't see a problem with removing the "case coverings" so long as the parts are easily identified in terms of values and there steps are taken to reduce the potential for something to short out against the body of the caps. Whether or not someone likes the sound difference that this "tweak" achieves is strictly a matter of personal taste.

As far as the reference to 47 Lab's gear, i've never heard any of it but i do know what it measures like. That is, they are very poor performers that are poorly designed and highly unstable. The signal that goes into these devices looks nothing like what comes out, meaning that there is a complete lack of accurate signal reproduction and / or large quantities of non-linear amplification taking place. Should someone like the sound that these products produce, so be it. I'm not about to say that someone can or can't like something. Using them as a point of reference for "quality" audio reproduction is something all-together different though. Sean
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Really not worth getting into here, but you should audition some 47 Labs gear when you get a chance - It will make you realize "measured performance" has absolutely nothing to do with musicality.

Keep an open mind and don't shortchange yourself.

Plastic does not sound good as a reducer, thats why they (and I) remove plastic from caps, and also transformers. Notice a nice improvement whenever I do both.

Yes I do notice more "air" which could have something to do with "ringing" I would suppose, but I do understand about the poor conductors manu. use to make them. Best to keep them short as possible!

Thanks to all those responding. Very informative discussion, and again, I'm awed by the collective knowledge of those on this board and the time they take to share it with others.

I was unaware of the need to check caps for damping, but it certainly makes sense after reading the above comments and links. In my particular amp mod, the Black Gates are so much bigger than the stock caps that they had to be mounted standing above the PCB on longer leads.

I'll definitely study the best way to damp them so they don't sing like tuning forks. I'm guessing that's exactly what they are doing in the present set-up now that the symptoms have been described.