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zentropa
Gold Member
USA
837 Posts |
 Posted - 03/29/2008 : 16:57:49
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was wondering if anyone could give a few recommended specs on caps...
Voltages... what is recommended?
50V, 100V, 200V, > 200V?
materials, how do they affect sound or what is most recommended?
mylar? polyester? tantalum? mica? ceramic? electrolytic?
is there a particular one that yields the "best" tone? warmest tone? brightest tone?
reducing the farad value usually does what?
increasing the farad value usually does what?
thanks in advance. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 03/29/2008 : 18:29:53
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Inside a pedal, the maximum voltage is the supply voltage (9 VDC for newer Boss, higher for other pedals - the pedals that run from 16VAC would have about 24VDC inside them). Note that if there were any inductors or transformers in the circuit (there aren't in pedals) you would need to look at the possible "flyback" voltages inside the circuit and rate the capacitors for that - but not to worry for pedals.
Long story short - I usually use 25V because that's common and the capacitors cheap. If you wanted to have some stockpiled for general electronics work (not just pedals) I'd say 50VDC would be more useful. The real consideration is whether they are too big physically to fit where you want to put them (higher voltage = bigger). I did my initial "seeing eye" mod to my DS-1 using 250V capacitors because that was all I could get, end they were HUGE, ugly, almost didn't fit in the pedal, and required nasty big holes in the circuit board - I swapped them later for 50V ones that were literally one fifth the size.
The engineering rule-of-thumb is to use capacitors that have a voltage rating 20% higher than the voltage you expect to apply to them.
Cautionary note - if the thing you are working on has tubes in it, all bets are off - you need special high voltage capacitors.
About capacitor type and how that affects the sound... the best I can say is that "opinions vary". I usually use metallised polyester because they don't break down over time, but respected opinions say tantalum is better for warmth. When I am buying larger lots to have spares on hand, I usually buy metallised polyester <shrug>.
The effect of reducing/increasing the farad value depends entirely (100%) on the circuit the capacitor is in. BUT. If they are 0.1�F or bigger, they are often being used for "bypass" (don't count on it) and in that case, bigger = more bass (but if the capacitor is already passing 99.9% of the signal, you won't hear it).
Laurie.
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Edited by - Laurie on 03/29/2008 18:38:09 |
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zentropa
Gold Member
USA
837 Posts |
Posted - 03/29/2008 : 19:01:56
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thanks much for the info.
:)
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Capacitor specs
