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Yes, there's plenty here to read

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In Reply to: RE: Outlet covers! posted by Enchantment1.6s on February 14, 2010 at 00:27:08

I haven't tried the commercial ones, but have mocked up my own from various readily available materials. YOu can use the archives here on Tweaks to find a plethora of ideas and opininons.

FWIW, 3 items to consider in outlet covers, whether you buy them outright or make them:
1) non-magnetic materials - stay away from steel or ferrous stuff
2) vibration controls
3) RFI controls

You can successfully use: ceramics, metals that are not ferrous, wood, plastic, nylon, etc. They'll all work differently.

For vibration controls, heavier and duller materials work best IMHO. That means that if you tap the materials and they ring, it's not the best, but if they thunk, you're better off. The commercial biggies (Oyaide) use duralimin, a very vibe absorbent aluminum alloy that is thick. I've tried non-ferrous metals of the thin variety, and they do some grounding if set up right and maybe some shielding, but they are not good for controlling vibrations. Wood, ceramic, nylon work better. In fact, the best to test it I've found can be those non-ferrous heavy cast metal outdoor outlet covers. They have weight and will do whatever grounding/shielding closing the metal box gives you (assuming your box in the wall is metal - if not, then you get nothing there.)

For RFI control, nothing I've found beats carbon fiber. I might try the Furu with CF over brass, but I think it's too thin to be tremendously effective. I'm using CF aircraft blanks (thick)over the top of the outlet cover and a couple of CF layers glued onto the back of the cover too. Those work very well.

Lots to play with.

Follow Ups:

RE: Yes, there's plenty here to read - rick_m 07:52:25 02/14/10 (4)
"For RFI control, nothing I've found beats carbon fiber."

Sounds reasonable. I'm curious how you are measuring it and what part of the spectrum you've found makes the most difference to your gear. I'm assuming that it's damping common-mode resonances, is that correct?

I'm interested in playing with it but have been concerned about the small size of the fibers causing the same lung damage that asbestos does. Do you machine it yourself?

Thanks, Rick
- OK - bartc 10:13:49 02/14/10 (3)
  No, I haven't measured it. It's subjective.
  
  I did try machining some thick pieces myself. Ended up with a faceful of fiber and figured out how stupid that really was! I can safely machine small sections with a Dremel now or a carbide tipped drill bit, but it's not really worth it.
  
  YOu can get the sleeves, which you don't need to work at all to put around plugs or cabling.
  
  You can also buy the woven sheets and laminate them yourself with resin. Another pain in the ass, but it works. I'd more or less cut it to shape before potting it. Better than machining finished product!
  - RE: laminate them yourself with resin - rick_m 11:27:11 02/14/10 (2)
    That sounds like a good, albeit messy idea. I'd rather have the mess than try and figure out the industrial hygiene I'd need in my garage to not wipe myself out. It's not quite the same thing as a solid block since the lams are probably effectively insulated from one another but the E-field is in the same plane as the sheets so it may not make any difference.
    
    Did you happen to compare the subjective performance of CF plates and clamp-on ferrite beads?
    
    Thanks for the feedback...
    
    Rick
    - Nope - bartc 11:52:31 02/14/10 (1)
      Don't use ferrites. Read up here as to why they are not favored for RFI control in audio. They can easily restrict dynamics and that's not what you want.
      
      CF is effective. This is not earthshatteringly good, just better. It's a damping phenom. Read up on Al Sekela's posts for theory; I'm just the tinkerer....
      - RE: Nope - rick_m 12:37:43 02/14/10 (0)
        
        In Reply to: RE: Nope posted by bartc on February 14, 2010 at 11:52:31
        
        OK thanks, I was just curious. I haven't encountered any problems using Z-beads but I understand others have, maybe it's all in how you use 'em. However when it comes to stopping RF they're pretty handy and even if you reckon that they have sonic side effects they might still be useful diagnostically to try and see if something that you are hearing is really likely to be a result of RFI.
        
        Regards, Rick
RE: Yes, there's plenty here to read - bradluke0 06:55:35 02/14/10 (1)
Hi all ! long time lurker and 1st time posting here . Tweeking always interests me as depending on what your system needs will depend on your direction in tweeking . If you system lacks highs the last you want is to damp out the covers on anything in the system or have them sitting on rubber feet . After all the resonance of the system is an average of all the resonaces in it . The reason a system may have too much upper midrange is there is probably 2 or more things resonating at that frequency in the system . You can prove this by playing a familiar vocal track and then putting maybe a dozen cd cases on top of your cd drive , oops... lots of upper midrange and lower treble ! The part that always entertains me are the people that say "cables dont have a sound or racks cant have a sound" . Everything in the system contributes to the sound , figuring out how to smooth out the system is always the challenge . Btw....different kinds of woods is all I will use to tweek......let the non-believers begin !!
- Sorry - bartc 10:14:44 02/14/10 (0)
  Source dried up. Bought a few to play with off eBay a few years ago. Then the source disappeared. Might be the same guy you're referring to.

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