Mallory 150 cap polarity

[Skiroy]

Hey guys I have some Mallory 150 M Capacitors I am putting in my strat tone pot. Only how do you tell which side is positive and negative. And what is the correct polarity orientation on the Pot?

[soundmasterg]

There is no polarity on Mallory 150 caps...hook it up any which way and it will work fine. As far as the pot, just hook the new cap up to the same place as the other cap was on it.

Greg

[Gtr_tech]

Well there kinda is....the outside foil for self shielding. But its not marked.....

[Chuck H]

I think we covered this here once and determined that it really doesn't matter. But FWIW the "standard" seems to be that you can read the printing on the cap in the direction of the outer wrap end.

[Rhodesplyr]

Well there kinda is....the outside foil for self shielding. But its not marked.....

You can determine the outer foil lead, but you need an oscilloscope to do it--at least that's the way I know how to do it.

[big_teee]

I wouldn't think it would have much effect on a guitar Pot?
Voltage is very low.
a Mallory 150 is 600+volt rated.
I doubt that it would make much if any diff. on a guitar, in that application!
B_T

[Jazz P Bass]

a 600 WVdc cap on a guitar tone control?
WTF.

[big_teee]

a 600 WVdc cap on a guitar tone control?
WTF.

I use my left over Amp Caps, and they work great.
I have some .022, & .033uf Sozos in my LP.
Probably not politically correct, but they sound the Bomb!
T

[Raybob]

Mallory 150s aren't consistent with which end has outer foil attached. Easy way to test without scope is with 1/4 plug soldered to alligator clips. Clip cap to both wires, plug in amp, crank it up, hold outside of cap with fingers and hear hum. Reverse polarity and try again. When holding it makes more hum, the wire attached to the 'hot' of the 1/4" plug is attached to outside foil. Much quicker process with scope.

[Enzo]

I for the life of me can't figure out why it matters in the slightest which end is "outer foil" in a guitar amp. I arrange the caps so they all have the print reading the same way for a professional appearance.


Yeah, I hear about shielding, yet I don't hear about what is being shielded from what. A typical cap feeds from a plate to a grid. ANY signal on one end is coupled to the other end by the very capacitance of the part.

[pdf64]

My interpretation of the idea is that the outer foil is best connected to the side that has the lowest impedance path to ground, eg to the plate side in that example. Then any EMI it picks up (from other wiring / components) goes to ground via the plate, rather than acting as an antenna to the grid.
Does any 'real' text book cover it, eg RDHX, or did it just originate from the musings of G Weber or similar?
Pete.

[Enzo]

It might matter in an RF circuit, but not here.

We can rationalize all sorts of things.

[Raybob]

According to Randall Aiken:

"Proper orientation of the capacitors will make the amplifier much less susceptible to outside noise, including hum, interference from fluorescent lighting, and tendency towards oscillations or frequency-response peaks and dips due to unwanted feedback from nearby signals within the amplifier, which can affect the tone of the amplifier (and is the reason why some people claim the amp sounds different if the caps are oriented in the opposite way - if there is no accidental coupling, there will be no tonal difference, but there will still be a noise benefit gained from orienting the caps the correct way)."

From Where to connect outside foil on capacitors

[big_teee]

According to Randall Aiken:

"Proper orientation of the capacitors will make the amplifier much less susceptible to outside noise, including hum, interference from fluorescent lighting, and tendency towards oscillations or frequency-response peaks and dips due to unwanted feedback from nearby signals within the amplifier, which can affect the tone of the amplifier (and is the reason why some people claim the amp sounds different if the caps are oriented in the opposite way - if there is no accidental coupling, there will be no tonal difference, but there will still be a noise benefit gained from orienting the caps the correct way)."

From Where to connect outside foil on capacitors

If it is that critical, then why are they not Marked?
Marking them at the factory would be the logical place wouldn't you think!
Rassling around trying to figure out how individual capacitors got labeled or marked, seems pretty extreme to me!
Sozos have a black mark on them.
They are suppose to all be according to the mark.
I've looked all over some of the caps and they look exactly the same on both ends.
T

[Chuck H]

OK... I mentioned this once before here and didn't think of it at the time of my last post.

Just to test this idea I did an experiment. I was building two identical amps for someone and I thought about it only after stuffing one of the boards. So one amp had the caps installed random, which ended up being over half oriented "incorrectly", and the other had the lead attached to the outer foil soldered to the lowest impedance end of whatever circuit they were in. There was no difference in noise at all. The two amps did sound slightly different though (very slightly). But I could attribute that to different tubes and part tolerances.

M2C