Orange Drop "polarity" ?

[nickt]

I've heard that it makes a noise difference which end of a non-polar cap you wire to the hot vs earthy side of a connection. My understanding is if the outer most foil is at earth potential then it shields the rest.

Questions:
1. is this true or a load of old bollocks?
2. If true which end of an OD 715 cap should be earthy?

Thanks!

[Dai H.]

look on the Aiken amps site. There is an article on this which covers a method to determine the outer foil. IMO, it hardly matters (but won't hurt anything).

[nickt]

look on the Aiken amps site. There is an article on this which covers a method to determine the outer foil. IMO, it hardly matters (but won't hurt anything).

Thanks - exactly what I wanted to know!

http://www.aikenamps.com/OutsideFoil.htm

[paulster]

And, just to add, I've found that most caps seem to have a random orientation when having the labels printed on them so it's not a means of identifying the outer foil except for those (Sozo, etc.) who specifically mark it.

I check and mark all of mine routinely, but I do it for potentially reducing induced noise than for improving tone.

[novosibir]

If you can see a vertical stripe printed onto the cap just after the value & voltage reading, then this side determines the outer foil.

Larry

[Dai H.]

this subject has come up many number of times, and on one occasion someone wrote to ask SBE (orange drop manf.) about the marking and they answered that the mark did not indicate outer foil and it was just random as I recall. If the concern is how to deal with noise, then I would study things like layout, noise theory, grounding, shielding.

[FUCHSAUDIO]

this subject has come up many number of times, and on one occasion someone wrote to ask SBE (orange drop manf.) about the marking and they answered that the mark did not indicate outer foil and it was just random as I recall. If the concern is how to deal with noise, then I would study things like layout, noise theory, grounding, shielding.

I learned a cool trick from a friend who built recording studios: Take an old tape head (from a cassette or reel to reel recorder). Attach with coax to a scope. Make sure the outside shell is grounded as well. A Bic pen casing makes a good "probe handle". This can be used as a "sniffer" for magnetic fields and audio radiation from components. It works well for transformers, chokes, and lengths of wire too. If you then take a signal generator and put it's signal into the cap, the direction with lowest radiated audio signal should be the side connected to the generator ground. Basically, this is because the outer foil is now shielding the input (inner) foil.

BTW: I also called SBE, and they confirmed the caps are "marked as they fall out of the manufacturing machine, into the printer, and the line doesn't indicate anything". Of course, the question is: why a line at all....lol

[paulster]

The Cornell Dubilier PVC series are definitely randomly marked despite the black bar. I've just tested another batch of them and the difference in noise level on the scope is too wide to allow for 'operator error'.

[Structo]

Back to the OP's question of whether or not it affects noise to the extent of going through the trouble of finding the "foil end" of a cap, in particular an orange drop cap?
I'm going to build a D'Lite 44 and it has a bunch of orange caps.
Would it be beneficial to orient the caps foil side towards the lower potential (ground side) of the circuit?
Or is this more of a obsessive compulsive thing?

From what I have read on the net there seems to be differing opinions on this and in fact whether or not Dumble himself did it.

[Johnhenry]

These Question's have been and will alway's be Asked ! here are a few more to think about !
Have you ever peeled the poly cover off of an Orange Drop ?
Did it look so simple a design that it looked like an 8 yr. old designed it ?
it's been made the same way forever, just a change in the outer cover ?
How does a roll of Tinfoil Block DC Voltage ?
How does a roll of tinfoil decide which Frequency's can pass ?
most of my testing caps led me to believe the MoJo is in your ear's,
When i look at the inside of the O/D i see a physical connection that is poorly designed at best, i see where there could be a difference in reading's from each end of the cap due to maybe a tight connection on one end and a loose connection on the other !,
I do know that each guy will have his own idea's and i love reading about what they think, it's what make's a forum interesting !
Johnhenry

[paulster]

When i look at the inside of the O/D i see a physical connection that is poorly designed at best, i see where there could be a difference in reading's from each end of the cap due to maybe a tight connection on one end and a loose connection on the other !

If that were the case rather than it being because of the outer foil then the test would still have achieved the same goal. It would still have proven that in one direction it was less susceptible to external noise, since that's what you're measuring with the scope method. And it would still hold true within an amp.

Whether it's worth the effort is open to debate, and I'm certainly not going to re-orient all the caps in one of my amps to find out, but I'm happy knowing that I'm minimising the opportunity for external influences, whether because of the outer foil or poor construction.

[Structo]

Is the Gerald Weber trick with the tin foil a reliable way to polarized these caps? I don't have a scope.
But I have a Fluke that measures capacitance.

[Johnhenry]

Paul, there's no debate on my part, i've seen the connection's being discussed here, I believe my eye's, there's no inner and outer connection on the O/D's i've took apart, and this i share with you as a fellow amp lover !
Johnhenry

[Johnhenry]

http://www.hallbar.com/capacitors.html
this is a great read if you got the time and should be a great help to anybody that want's to learn more about capacitor's.
Johnhenry

[tele_player]

Paul, there's no debate on my part, i've seen the connection's being discussed here, I believe my eye's, there's no inner and outer connection on the O/D's i've took apart, and this i share with you as a fellow amp lover !
Johnhenry

I've taken them apart too.
They are rolled up foil and insulator, and for it to work as a capacitor, one (and only one) of the legs has to be connected to the outermost foil.

Or are you saying the OD's don't work?