Hello there,

Looking at some data sheets, it looks like the orange drop capacitors are no longer marked with the lead that has the outside foil. The outside foil is supposed to go to ground for audio work. Is this true or are there some that are still marked properly?

Then I got to thinking. Since orange drop caps have been around for a long time, there must be better caps now for audio work. Any ideas?

The application will be inside an electric guitar for the tone control. I think they are typically 0.022uf but may vary.

 

Film caps seem to be the standard for good quality audio. They tend to be stable, have a reasonable dissipation factor and free from microphonics. A minute or two with a signal generator and sniffing around with a scope probe should allow you to figure out which lead is the outside foil.

 

Film caps seem to be the standard for good quality audio. They tend to be stable, have a reasonable dissipation factor and free from microphonics. A minute or two with a signal generator and sniffing around with a scope probe should allow you to figure out which lead is the outside foil.

Hi,

My main question was not really about testing them, it was about the change from marking them to not marking them, if that is the standard now. All the ones I had in the past had the outside foil terminal marked. I thought it was strange that they seem to have stopped marking them, but perhaps not all manufacturers did that. I know you can test for this, but that's not really what I was questioning about. Thanks anyway though.

 

I haven't used an old, huge, high voltage "orange drop" capacitor for about 55 years. Since then I used small, low voltage film capacitors.

I think the outer foil on the old capacitors picked-up interference in high impedance circuits but made good shields when connected to the lower impedance (usually the signal source).

 

Hi,

My main question was not really about testing them, it was about the change from marking them to not marking them, if that is the standard now. (some text removed for clarity)

The "thing" is that once you have that figured out you should be able to rely on the markings from then on to know where the outside foil is.

Perhaps with the small footprint of SMD components somebody felt that it is not as important to know which lead was the outside foil since the surface area is much smaller on those old (and great) orange drop caps.

 

The "thing" is that once you have that figured out you should be able to rely on the markings from then on to know where the outside foil is.

Perhaps with the small footprint of SMD components somebody felt that it is not as important to know which lead was the outside foil since the surface area is much smaller on those old (and great) orange drop caps.

Hi,

Not sure what you mean about the reliance on the markings from then on to know where the foil side is. The problem is that they are not marked when you buy them, that means you are stuck testing them as you noted. I thought it was dumb for the manu's to stop marking them.

 

I haven't used an old, huge, high voltage "orange drop" capacitor for about 55 years. Since then I used small, low voltage film capacitors.

I think the outer foil on the old capacitors picked-up interference in high impedance circuits but made good shields when connected to the lower impedance (usually the signal source).

Hi,

All I know at this point is the recommendations I have read is that the foil side gets connected to ground. I guess that is to make it less of an antenna. I don't know if it really makes a difference either, but you know how these audiophiles are (ha ha). They 'feel' that one thing is better than the other, and there are various differences of opinion.

I watched one video online where a guy tested a handful of different caps, but then never drew any conclusions, so no help there

What kind of caps did you use, the smaller ones? They recommend the orange drop type but I have a strong feeling that is because that is all that they know and they don't know that better caps might be around now.

I checked a rather expensive guitar I have and sure enough, an orange drop cap in there with no markings

 

Then I got to thinking. Since orange drop caps have been around for a long time, there must be better caps now for audio work. Any ideas?

Lots of different ones out there, but one of the nicer caps than them are polystyrene type but for a guitar amp I would glue them in place so they don't snap off as their leads are a little flimsy. I only use wounded film caps instead of box stacked types because they have a better distortion profile. PTFE film are nice as they are a newer style cap that offers the superior performance of polystyrene but a little bit more rugged and comes in larger capacitance values.

The line used to denote the foil before sprauge was bought out, now it doesn't mean anything and of course the sbe are not marked and are not constant. Poly films I like are solen and dayton audio film and foil.

 

The outside foil lead was marked on old huge high voltage orange drop capacitors because people did not want to hear mains hum picked up when a coupling capacitor was acting like an antenna.

 

Knowing which side was the outside did matter when capacitors were used for bypassing screen grids in many circuits built with VACUUM TUBES. It might possibly matter in current technology circuits in noisy environments. BUT the electrical field in a low lwvwl circuit powered by ten volts is much less than the electrical field produced by the plate signal with a 200 volts DC supply and a 10 volt swing. AND, in general, the impedance level in solid state electronic circuits is much lower than in the old "fire bottle" circuits.