Welcome! Need support, you got it. Or share you ideas and experiences.
In Reply to: Re: sheilding output caps posted by 5th of 5 on July 31, 2004 at 17:05:57:
The tape looks like a good idea, as all you need the tape for is to keep it from unwrapping while the drain wire is being put on. I am not an EE but it my understanding from RF work the the shield must be grounded to be fully effective. Another thing just came to mind with this and that is in effect are we going to change the capactitance with a grounded shield. Maybe someone more in the know would be able to elaborate on this. Seems like we are making a dual stage cap. ?
do you think running the adhesive copper tape to ground after wraping around cap would work?
A qualified yes to the question, and the qualifications are 1) the the copper tape is actually conductive over its length, and 2) that the foil is not protected by an outer coating or film preventing a good contact with the drain wire, and 3) that you don't just use the tail end of the tape and stick it to ground expecting a connection, probably won't work that way. With these things in mind I am sure the tape would work well.
Good question Terry!
Does anybody have an answer?
Assuming that the circuit is well designed and grounded properly, the only other source of significant noise (I would think) would be RF/EMI interference.
How far can we go (within reasonable effort and cost limits) to eliminate this?
For us kit builders and DIY types, I think this is possible considering the added expense is just a few dollars of copper foil and wire and maybe a few hours of extra time.
So does anybody know if we are actually changing the circuit by doing this and what other areas would need attention?
I would think there would be lots of room for improvement in the transformer shielding because we can spend a lot more time there than any manufacturer typically could.
Ultimately that may be as good of a solution than going to a separate remote power supply.
Am I full of hot air, or are we on to something here?
Also, how good is that 3M copper shielding tape?
Would we ever need to double or triple wrap anything?
Is there anything better?
that copper tape is pretty expensive - probably why I never bought a roll. However, a few weeks ago when I sourced parts from Michael Percy for a CD transport mod, I just had $20 laying around that was asking to be used to try a tweak I had not sampled before...
Enter Stillpoints ERS EMI/RFI Suppression cloth...
I got it a few days ago and before cutting it up for my CD transport project, I tried it by simply placing the sheet near the back of my foreplay, between tubes and tranny and power lines, not even taking it out of the packaging. That made an immediate difference! Things were clearly more refined, natural and smoother (make mental note to self - build that external PSU soon!). I'll be adding this stuff to a lot of my components. Once I stuffed the insides of my DAC with a few strips of this cloth I had another ear-opening experience. I'm not sure if I'll go as far as wrapping ICs and power cords with it (the adhesive tape cloth is rather expensive atover $4/foot for 1" tape), but then I may just want to see what happens if...
Nevertheless $20 for a 8.5x10 sheet of paper with some cut up fine metal strips and other secret ingredients is pretty expensive, though. Perhaps I'll study some paper making and come up with a DIY version of this one day.
reviews (scroll down to the paper thing)
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