Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: nateflanigan on November 17, 2010, 09:38:59 pm
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What voltage should tone stack caps be?
Thanks
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That depends on the circuit. 500V will cover most all circuits.
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In the Fender stack, the two big caps MUST block the no-load supply voltage. 400V is often OK for many years. The pFd cap on Treb has negligible voltage, but in that value you can get 500V as cheap as any other.
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You could always put high voltage (500vdc or so) cap before the tone stack, which would allow you to use low voltage caps in the stack. The cap should be at least .022 uf or bigger if you don't want to change normal frequency response as if the cap wasn't there. This may seem economical, but it's really not - modern caps at those values are cheap. Just an option if you are eager and have some low voltage caps in the right values on hand.
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thanks guys. It's for some AB763 tone stack tweaking that fresh_start has been helping me with. I ordered a 100v cap by mistake. It's such a drag when you're like one part short of finishing something up.
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You could always put high voltage (500vdc or so) cap before the tone stack, which would allow you to use low voltage caps in the stack. The cap should be at least .022 uf or bigger if you don't want to change normal frequency response as if the cap wasn't there. This may seem economical, but it's really not - modern caps at those values are cheap. Just an option if you are eager and have some low voltage caps in the right values on hand.
Ditto; except for the decimal point. Per the Rule of Tens, that hi voltage cap needs to be at least 10X larger than the largest cap in the tonesatck = .22 or .47uF.