Using Non-Polarized Caps?????

racfan9

racfan9

Super Member
Hey Everyone, Just received my new caps from Antique Electronic Supply to finish up a recap job on a Maggie 8103 amp.
When I started looking at them I noticed there was no neg. markings on any of them. I contacted Matt at Antique Electronics and he said they were all non-polarized so it made no difference which way they were installed. So I guess my question is, can these be used for a complete re-cap job? I know Non-Polarized caps are used in speaker crossovers but not for a complete re-cap. Please let me know so I can send them back and get the correct ones.

Thanks,
racfan9
 
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Yes, they're just more expensive and physically larger than a polar cap of the same ratings would be. They will work fine though.

Wonder if they started selling NP caps to eliminate people calling and screaming that their new parts exploded after being installed backwards.
 
gadget73 said:
Yes, they're just more expensive and physically larger than a polar cap of the same ratings would be. They will work fine though.

Wonder if they started selling NP caps to eliminate people calling and screaming that their new parts exploded after being installed backwards.
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Good Point, I'm sure there's been a few that got a big surprise.
 
Only standard electrolytic and tantalum capacitors care about polarity. Film capacitors do not have true polarity markings, or care how they're wired; some of the older paper capacitors had a marking on one end for "outer foil", but this usually doesn't matter in most applications when using modern film capacitors. If the cap you're replacing doesn't have + and/or - markings on the case or in the schematic, you can install the new cap in either direction.
-Adam
 
Are you replacing power supply electrolytic capacitors, or coupling capacitors? What are the values?

Like gadget said, film caps will be much larger than polarized caps, but last much longer because they won't dry out. Many old Williamson amplifiers used large film capacitors mounted to the top of the chassis, usually around 8 to 10uf 600v.
 
NP electrolytics exist too. Not as big as film caps of the same value, still typically bigger than polar electrolytics though. Kind of an in-between thing.
 
Not sure about swapping NP with polarized in every situation. While performing a recap on a MQ102 equalizer, I used a NP electrolytic cap and it swelled up after heavy use. I figured it must be a bad cap and replaced with same, with the same outcome. I repeated this 3 time (I guess I'm a glutton for punishment) with the same outcome.

I finally installed a polarized cap and have had no problems since. Before anyone asks, the NP cap I used was rated the same as the original, with a higher voltage rating to boot!
 
may have something to do with ripple current ratings. There is more to caps than just voltage and capacity, but those other values aren't printed on the side.
 
I used polarized for the power supply. The NP's will be for the coupling caps and a few other caps in the circuit.
 
eiraved said:
Not sure about swapping NP with polarized in every situation. While performing a recap on a MQ102 equalizer, I used a NP electrolytic cap and it swelled up after heavy use. I figured it must be a bad cap and replaced with same, with the same outcome. I repeated this 3 time (I guess I'm a glutton for punishment) with the same outcome.

I finally installed a polarized cap and have had no problems since. Before anyone asks, the NP cap I used was rated the same as the original, with a higher voltage rating to boot!
Click to expand...
The adage I learned was, "If the cap. has a voltage across it, always replace with a polarized cap. If it doesn't, you can use either type." The NP cap. you replaced with a polar. electro. may have had a voltage across it.
 
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