October 19, 2020 at 5:44 pm #15300SliderParticipant
I’m sourcing the parts for a Colortone Overdriver. I’m curious about some of the listed capacitor voltages, particularly C3. Is it critical that this 220pF cap be 63v as opposed to something more usual like 50v? I’ve read about substituting 470pF or 560pF, but I don’t see anything about voltages. I want to understand what I’m dealing with here before going to the effort of ordering an unusual value.October 19, 2020 at 6:27 pm #15301BillyModerator
The rule of thumb for capacitors is at least twice the circuit voltage most gpcb circuits are 9v
Voltage rating is also an indication of physical size especially for electrolytic and greenie type metal film caps so for those you’re better not to go larger than 63v and 100v respectively anything over that can run big in size and too big for pcb work
With ceramic and box type film caps it’s not as critical 100v is usually the same as 50v
Another important consideration for box film, metal film etc is lead spacing you want 5mm some wima caps for example have 7mm and over lead spacing
Voltage ratings are generally standardized (16, 25, 35, 50, 63, 100) so you go with the nearest you can get
If you like to run your pedals at higher voltages just make sure you have suitably rated capacitors
Most suppliers should give you that information or it’ll be in the datasheet any circuits that require specific voltage ratings will usually tell you in the build docs
The beginners guide to effects pedal components on the guides page covers information on capacitorsOctober 20, 2020 at 12:19 pm #15305wilkie1Moderator
Excellent detailed advice, Billy!October 20, 2020 at 1:35 pm #15311SliderParticipant
Billy, Thank you for the thorough reply to my question. When I first read it I still did not understand why the 63V rating was next to the first few capacitors on the parts list CTO v2. I read it a few more times, read through the section on capacitors in the guides page, and spent some time with the actual PCB.
I was interpreting the 63V as a minimum rating and now I’m thinking that in this case it is a maximum rating due to size consideration. I have built pedals where there wasn’t room for a particular capacitor, especially something like a 1uF 100v box capacitor.
One positive outcome of investigating this is I’ve learned to read more specs when ordering capacitors; looking at voltages, size and spacing. Thanks for the help.
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