electrolytics polarity????

[heisty]

Hi guys i still get confused about which way to wire a polarised cap to cathodes, some caps just have a arrow with black insert on one end , others like sozo have a band at 1 end , and blackgates have short and long leads
What is easy way to remember ,call me dumb , could be memory lose happening here

[paulster]

Electrolytic (polarised) caps will have an arrow pointing to the negative end. You can confirm this as the lead will be soldered directly to the end of the capacitor can, whereas the positive end will exit through a tiny rubber grommet. (There is an exception to this, which is that tantalum caps mark the positive end, but you probably don't want to be using them in guitar amps anyway.)

These are the ones where it's crucial to orient them correctly and, for cathode caps, the negative end goes to the ground buss.

For non-polar caps they may identify the outer foil with a black band, as Sozo has started doing. It doesn't matter which way round you connect these, but you can obtain a slight reduction in induced noise by connecting the outer foil to the lower impedance side of the circuit. For cathode caps this will be ground as well, but for coupling caps it will be the plate side as opposed to the next stage grid (B+ is low impedance, as is ground).

[heisty]

Cheers mate , might be ingnorance on my part but with the electrolytics do u connect the pos or neg side to cathod pin on tube or the other way round

[paulster]

Positive side of the cap to the cathode pin, negative side of the cap to the preamp ground connection or buss.

[lastwinj]

Electrolytic (polarised) caps will have an arrow pointing to the negative end. You can confirm this as the lead will be soldered directly to the end of the capacitor can, whereas the positive end will exit through a tiny rubber grommet. (There is an exception to this, which is that tantalum caps mark the positive end, but you probably don't want to be using them in guitar amps anyway.)

that would be on axial caps. radial, you wont be able to tell if a lead is welded to the case.

nothing wrong with tantalum. sound just fine. biggest problem i have found in tant are the eopxy bead ones. yucky. nice, high quality ones, such as a kemet T110 or a sprague 150d are just fine. I wont go into wet tantalum, which are hideously expensive (40 for a 2uf 50v cap....)

germ

[Tdale]

I kept looking at the arrows pointing to one leg, and didn't understand how to find out if that leg was positive or negative. Then it occured to me that there was a "-" in the arrows......

Tommy

[David Root]

With can caps, there is no arrow on the side of the can. You have to look at the terminals on the the end of the cap. Most have a separate ground terminal, which is either color coded or otherwise marked - eg crosshatched. Usually there is identification of the ground terminal on the side of the cap, but some can caps use the exterior can as the ground, and it will have one or more soldering tags on its rim.

Also, if you're using electrolytic caps in a fixed bias supply, which is of course a negative supply, you must reverse the standard orientation and ground the positive end, or you'll blow up the cap(s).

[Johnhenry]

Tant's and Radial caps will both normally have a Short and a long wire, Short lead to ground and long lead to voltage.
Johnhenry