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Anybody try air variable caps for RIAA networks?
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Posted on October 31, 2001 at 08:20:53 | ||
Hi, I'm working on another phono pre, which you know is a difficult thing to do. I would rate doing a good phono stage as the hardest project, followed by power amps, followed by line stages. The problem is that you have to get the $%#@ RIAA frequency response to less than a dB. Practically, this is tough because it varies based on the actual plate impedence of the tubes involved, among other factors. Most of us don't have spectrum analyzers to help us measure this. Anyhow, another problem is getting quality caps at those tiny values. I need a 750 pF value, which by golly is available as an air variable type used in radio receivers. Air is certainly an excellant dielectric, and the cap has the bonus that it can be accurately tuned. How does it sound? Has anybody tried this? The only downside I can se a-priori, is that they tend to have thick plates, which in my experience probably would not sound too good. Dan |
Re: Anybody try air variable caps for RIAA networks?, posted on November 1, 2001 at 00:11:49 | |
Go on try it Dave, I've been bored to death lately we need a filip!! |
I would be kinda worried about arc-over, myself. (nt), posted on November 1, 2001 at 07:45:29 | |
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Re: I would be kinda worried about arc-over, myself. (nt), posted on November 1, 2001 at 10:28:23 | |
Looking down your list dave I suppose bath water comes somewhere between urea and h2o, about 2 then! |
Just don't let Zelda drink out of them (nt), posted on November 2, 2001 at 07:54:55 | |
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Joined: April 6, 2000 |
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