I wouldn’t worry about precision there. They are usually specified to -20% +100%. A 5600uF is fine for the 5000uF
Of course and I realize that. But anal me insists we be as close as possible.
![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif.pagespeed.ce._hfWAz_QHO.gif)
Been there. I’ve untrained myself from that way as it was getting expensive ![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif.pagespeed.ce._hfWAz_QHO.gif)
Meh. I'd have slapped a couple 2700uF on there so I could keep the leads through-the-PCB short, which is kindof the point of that adapter and all the different hole patterns it supports. Leaving those leads long like that fucks the ESR of the cap right to hell. ![Confused :-//](https://www.eevblog.com/forum/Smileys/default/confused0024.gif.pagespeed.ce.5xOqKkq0Co.gif)
mnem
*unplucked*
I disagree. Given that the modern replacements have lower ESR than the originals I see zero net impact.
Yep. ESR on them isn’t that important. They’re just there to stop the regulators dropping out at 100/120Hz. Anything which requires lumps of current is well decoupled with tants. Now if you replace the tants that’s a different thing. 2x the value low ESR electrolytics are fine there. But main supply caps, any old shit will do.
It has nothing to do with that. It has to do with tiny lead diameter. You can get away with the tiny leads on modern caps when they're 1.5mm long; the wire resistance means diddly. Make them 10mm long and that's a different story altogether. I've seen it demonstrated time and again in high-current amplifiers and the high-current ESCs we use in our quadcopters.
The instantaneous voltage sag that creates is something you can see in real world performance, in dB Drags and in how the quad handles or flips upside down when it should be able to right itself.
And I've seen it measured with a scope by people a lot smarter than me, who know how to measure these things correctly.Now as to whether it is going to matter in
this application... probably not. As old man Kirsch used to say:
"Choobs are a voltage amplifier; transistors are a current amplifier." (yes, I know this is a gross oversimplification; he said it to make a point about the difference in the way you have to think when designing these circuits most of the time) Meaning the current loading of this system is much lower, so we probably won't see a damn bit of difference.
But it's
good practice to keep those leads as close as possible to
"just long enough to go through the PCB", because that is how they're designed to be used.
mnem
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