Conditioning, Hipotting (Hi-Pot) Film Capacitors

[ridikas]

Conditioning Film Capacitors - Is the process of taking a metalized film capacitor (polyester, polypropylene, etc.) and applying a larger than normal voltage. Since these types of capacitors are "Self Healing," any pinholes which formed during the winding process, or the manufacture of the dielectric film arc and vaporize the metal around them. The film then melts around and heals the capacitor.

1.) Which manufacturers condition/Hi-Pot their capacitors? Jeff Glowacki from Sonic Craft performs this process on every single Sonicap that he sells. At twice their rated voltage. So I will start the list with Sonicap...

2.) Can multiple film holes in the metalized capacitor cause noise? Especially if the capacitor is directly in the signal path, i.e. coupling?

3.) Can this be attributed to capacitors sounding better after break-in? Since the voltages and current in audio is rather small, the capacitors may never self heal all of their pinholes, even after extensive use. So in theory, conditioned capacitors should always sound better.

4.) How can one construct a proper Hi-Pot tester and, or capacitor conditioner?

5.) Any personal experience from members on this board regarding this topic?

[ridikas]

No one is interested in discussing this?

[DigitalJunkie]

FWIW, Just an observation I made with a tube amp I was working on;
I replaced only the coupling capacitors with new Sprague 'orange drop' types.No other parts-changes were made. Upon firing up the amp,there was some static-like noise,and a couple of 'pops' from the speakers for a couple seconds,after the last 'pop',everything went quiet,and the amp worked perfectly ever since.

Maybe it was capacitor 'break in',or maybe it was something completely unrelated. I don't know. Just something to ponder.

[Speedskater]

Hi-Potting a new capacitor to make it a better capacitor doesn't seem to be a good idea to me.
When i worked in motor drive R&D, we would occasionally over-stress some film capacitors, then un-wind them to see how the film did.
Just for fun we sometimes Hi-Potted small film caps. It might take 1500 Volts to fail a 50 Volt unit.

[ridikas]

What if the capacitors are connected to a power supply of lets say 3/4 their rated voltage and cooked for a while? Would that be enough to self heal all of the imperfections? Therefore making a better capacitor that has less noise?

[SY]

If your cap needs that, change suppliers.

[ridikas]

The suppliers have nothing to do with this...

[SY]

They have everything to do with it. Properly manufactured capacitors don't have spots that need repair, especially with low voltages. If they do, the supplier is incompetent. Properly manufactured capacitors don't have noise (other than the Johnson noise of their ESR which is beyond microscopic).

[sakis]

if one can hear an obvious difference after conditioning we might have something to talk about here even though my physics talk about other things ....

[Tony]

Originally Posted by ridikas

Conditioning Film Capacitors - Is the process of taking a metalized film capacitor (polyester, polypropylene, etc.) and applying a larger than normal voltage. Since these types of capacitors are "Self Healing," any pinholes which formed during the winding process, or the manufacture of the dielectric film arc and vaporize the metal around them. The film then melts around and heals the capacitor.

1.) Which manufacturers condition/Hi-Pot their capacitors? Jeff Glowacki from Sonic Craft performs this process on every single Sonicap that he sells. At twice their rated voltage. So I will start the list with Sonicap...

2.) Can multiple film holes in the metalized capacitor cause noise? Especially if the capacitor is directly in the signal path, i.e. coupling?

3.) Can this be attributed to capacitors sounding better after break-in? Since the voltages and current in audio is rather small, the capacitors may never self heal all of their pinholes, even after extensive use. So in theory, conditioned capacitors should always sound better.

4.) How can one construct a proper Hi-Pot tester and, or capacitor conditioner?

5.) Any personal experience from members on this board regarding this topic?

hi-potting is a destructive test, it weeds out capacitors with low quality insulation destroying it in the process.....

this is the first time i heard such........for a capacitor, what made you think you should do this?

normally, big motors, distribution transformers, and hv cables are high potted according to manufacturer's recommended standards, or SHELL DEP or sometimes even according to government standards,