Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dude on April 19, 2021, 02:53:43 pm
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Putting two small caps, say two 50uf's @ 25V in series, do I need balancing R's? If so, what valve should the two R's be using 25v caps.
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https://www.illinoiscapacitor.com/pdf/Papers/voltage_balancing_resistors.pdf
Honestly, I usually wing it. But this is the book answer.
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How many volts total across the series combination?
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Putting two small caps, say two 50uf's @ 25V in series, do I need balancing R's? If so, what valve should the two R's be using 25v caps.
You’ll get 25uF and (if you use equal balancing resistors) 50V capability.
But if you need less than (say) 20V all up, then you can do without balancing resistors.
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How many volts total across the series combination?
Just don’t have any 25uf’s in stock for cathode on 12ax7, (1st or 2nd stage), wanted to try the 25uf vs the 4.7 l have now. Voltage is probably less then 3v.
Tubeswell, so at that low voltage you say forget the balancing R’s.
It’s just temporary, if l like the tone l’ll get the correct value.
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if it's just for cathode bypass why not just try a 50uf there and keep it simple? for a 100k/1k5 typical fender stage the difference between 25uf and 50uf is imperceptible (0.03db at 82hz)
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I don’t think so, l definitely can hear the difference between 4.7 and 25uf
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I don’t think so, l definitely can hear the difference between 4.7 and 25uf
Yes, but with larger value caps, I think it's because once you get to 25uF there's very little to gain, with guitar, by going larger.