zap
Rookie Solder Flinger
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Post by zap on May 13, 2006 22:40:01 GMT -5
First off I'd like to say hello to everyone on the board! Lots of good info here. I read in Quieting the Beast to use a metal film capacitor, and that a .022uf 400V could be substituted. In my confusion about the different capacitor types, I ordered Boxed Metal Film caps. (Mouser p/n 581- BN074I0233K) Are these ok to use for this mod? I'm a little blurry on what the different names actually mean. To me they look like a film cap in a square plastic box instead of exposed. I've tried to read about different cap types, but I can't seem to find anything that explains these details. Thanks for any help.
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Post by fobits on May 14, 2006 9:22:30 GMT -5
First of all, welcome to the forums ;D
There seems to be quite a bit of confusion about this cap. Just within recent memory a few other people have asked about it.
According to the instructions, it should have a value between .22 and .47 uF - NOT .022 uF. The voltage rating should be 400v.
A .022 uF cap would be reasonable on a tone control, but this one has a completely different function. It's supposed to protect you from being electrocuted if something goes wrong inside the amplifier.
I'm not familiar with the different types either, but so long as it has the right capacitance and voltage rating, I doubt if it makes a difference.
In fact, there has been some serious questioning here whether it serves a useful function at all. It will only protect against dc voltage and current. 60 Hz ac would go right through it. The only type of amp which has dangerous levels of dc voltage is a powerful tube amp. Transistors operate on low voltages.
So, assuming that you do have a big vacuum tube amp, is there a way it can fail which would send a great jolt of dc voltage up the cable? That question was posed a while ago, and nobody could think of how it could happen.
I'll probably catch hlll for saying that, and encouraging you to electrocute yourself, but that's how I see it.
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zap
Rookie Solder Flinger
Posts: 5
Likes: 0
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Post by zap on May 14, 2006 20:25:46 GMT -5
LoL! Perhaps placing the amp in the shower, or settin it out under a lawn sprinkler while playing it? (OF COURSE NO ONE SHOULD EVER DO THIS)Nothing like a good old fashion experiment with electrocution. My cousin always said there's no use being stupid unless you can prove it. I knew I was gonna buy the wrong ones. These have short leads and look like they belong on a circuit board. I'll try them on tone controls like you suggested. I have a 65 Twin Reverb Reissue blackface from about 98 I think. None of my guitars have the strings grounded to the circuit and with just star grounding alone, and some with sheilding & star grounding, they are pretty darn quiet. I just wondered if on top of some shock protection, if the cap made things a little more silent.
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