16 volt caps at 18 volts?

[rpjones]

I built the AMZ mini-booster with parts from Small Bear. His electrolytic caps are 16 volt rating. Is there a danger of using an 18 volt power supply to power the booster? I used it very briefly and liked the sound, was reluctant to keep it up for more than a few seconds. Jack Orman specifies 25 volt or higher caps but Small Bear only listed 16 volt rating in his stock list.

[Joecool85]

I wouldn't do it. Caps can explode with overloading the voltage...

[burnt fingers]

18V -> 16v cap =  kaboom

[brett]

Hi.
I take no responsibility for what you do with this information.  It is just information, not advice.

I have connected large caps (4700 63V polarised electrolytics) the wrong way around, and they have gone kaboom.  Danger!
I have used a couple of medium-sized electrolytics a bit over-voltage (e.g. 25V at 33V) and they have lasted several years and never gone boom.
I have (accidentally) used a small 63V greencap way overvoltage (250V) for about one year and it did not fail.

In my opinion, using a cap at more than its rated voltage almost certainly reduces its reliability.  But from what to what is a tough question to answer.

[George Giblet]

As a kid I often ran 16V caps at 18V, never had one go.  I've also ran 40V caps at around 42V, never had a problem.  These items ran for many years.

As a kid I ran a 10V cap at 18V and it went boom - very cool.

As a designer I would never run caps over voltage, you just don't make dodgy design decisions like that.

This is from some AVX brand capacitor data:

"Indeed, maximum permissible surge voltage for electrolytics is 1.15 or 1.2 (for the better) VnDC."

[Mark Hammer]

Even if they don't go kaboom, caps are only guaranteed to be on spec (leakage, capacitance, etc.) at the rated voltage and below.  Kaboom is unpleasant, and so is a unit that doesn't sound at all like it was supposed to.

That's two reasons not to do it.

BUT.....

It depends where you are using the cap.  Very often the caps in the audio path have more relaxed working voltage requirements.  If the cap is supposed to help smooth out the power lines, it clearly HAS to be rated at more than the supply voltage.  If it is intended to smooth out the Vref, it has to be rated above half the supply voltage.  If it's an input cap in the audio path, the odds are that it doesn't have to contend with anything bigger than a volt in amplitude.

[rockgardenlove]

I wouldn't do it. Caps can explode with overloading the voltage...

SWEET!

I'll be sure to try blowing up some caps in my spare time...sounds like fun

[jonathan perez]

one time me and my uncle ran 500 volts into a 100 volt cap......


AWESOME!!!!!!!!

then we figured wed go bigger and do a 1000 volt cap, and run 3000 volts into that!


KKKKKAABOOOOOOOOOOOOOMMMMMM!!!!!!!!!!!!!!

sorry...i miss spending quality time with my uncle...

my advice:
NEVER run more than the maximum voltage through a cap...UNLESS YOU LIKE BLOWN UP STUFF!!!! WHOOOH!

[Ben N]

one time me and my uncle

went riding down from south Colorado, West Texas bound...
and I left his dead ass there by the side of the road!

Sorry, sometimes I can't help myself