Standard aluminium electrolytic capacitors -ripple current question

[thekid777]

Hi,
why the older series of standard aluminium capacitors (85° general purpose) had higher ripple current compared to the current series?
Do you know any radial capacitor of this type (not 105°-low esr, just regular ones) made today which would have high ripple?
Thank you

 

[Khron]

There are 105C series as well, that are NOT low-ESR.

Is there any particular value of minimum ripple current rating you need for your application?

 

[mrclunk]

I'll use higher voltage rated caps if i need higher ripple current. Physically larger caps can normally handle more current.

 

[trobbins]

why the older series of standard aluminium capacitors (85° general purpose) had higher ripple current compared to the current series?

Perhaps best to identify the make and model of e-caps you are referring to here so we better understand what your concern is, as it's a bit like saying why an older car has a higher torque engine than a newer car.

 

[CJ]

You gave a signal generator and a scope? Maybe both in the same package with a DC offset knob?

Hook up a square wave to the cap , crank it up all the way with some DC offset and compare waveforms. This will tell you the truth as sometimes spec sheets are tilted.

You need a standard to compare with, like one of the old caps you are talking about.

You can use a sawtooth wave also.

 

[PermO]

I have a mixer PSU where the main big capacitors (Rubycon) started to bulge in a couple of years.
I figured those where not specced right for this position, the PSU also got hot.

So I went for capacitors that could handle the biggest ripple current I could find (Cornell Dubilier) and replaced them.
Now there was a lot less heat in the PSU to my surprise.

The biggest surprise is what happened to the sound of that mixer, low end got punchy and tight, it was a huge overall improvement I did not expect to happen.

 

[Khron]

I have a mixer PSU where the main big capacitors (Rubycon) started to bulge in a couple of years.
I figured those where not specced right for this position, the PSU also got hot.

Might they have been fake, even? "Rukycon" or "Rulycon" caps are not unheard of...

If they were bulging, they may have lost capacitance, so no wonder the low end of the audio might have suffered...

 

[JohnRoberts]

I have a mixer PSU where the main big capacitors (Rubycon) started to bulge in a couple of years.
I figured those where not specced right for this position, the PSU also got hot.

So I went for capacitors that could handle the biggest ripple current I could find (Cornell Dubilier) and replaced them.
Now there was a lot less heat in the PSU to my surprise.

Higher ESR capacitors will develop internal heat from I x R... Lower ESR means less heat.

The biggest surprise is what happened to the sound of that mixer, low end got punchy and tight, it was a huge overall improvement I did not expect to happen.

This is less obvious but certainly a good thing.

[edit- if you still have the old cap, it might be interesting to measure the value. That could explain a sonic difference. /edit]

JR

 

[PermO]

I don't have the old caps anymore, this happened years ago.

The PSU is known to be a bit under specced for the 32ch version mixer.
Smaller frames also run the meterbridge from the same PSU, with the 32ch you get a second PSU for the meterbridge to reduce the load on the mixer PSU. When I noticed the bulging caps I swapped the PSU's and fixed the one with the problem. To switch PSU back after the job was done, so I was allready no longer "listening to bulged caps" in this situation.

I did find the original caps on Mouser and used the configurator to look for ones that were better specced, in this case the Cornell Dubilier I found could handle ripple current way higher, like 5 times more compared to the original ones.

They were also very expensive, like 5 times more...

I don't regret buying them.