mallory 160 series capacitors

[scole]

i ordered these by mistake. http://www.cde.com/catalogs/160.pdf
i purchased .47uf 100v for use in bias circuit, are they ok to use?.

[OverDriven]

As long as the ones you bought are rated at a high enough voltage. Other than that, they just look like a different form factor of the 150's.

[scole]

the leads line up perfect with the lugs on a terminal strip. i can mount the bias components on a terminal strip, and just bolt it in to an amp such as a tweed super to make it adjustable bias.

[tubeswell]

Are you talking bias supply caps? I thought you needed to use polarised (i.e. electrolytic) caps for bias supply (I thought they needed to be reverse-biased to smooth out the negative voltage rectified by the diode)?

I understand that if they are rated about twice what the bias voltage sees, that is okay.

[Enzo]

Yeah, WHERE on the bias circuit?

If you meant to buy 47uf/100v caps as filter caps for the bias supply, then no they won't work. They are only .47uf. Unless you want to put 100 of them in parallel...

But they will work in place of a regular old .47 film cap as long as the circuit is below 100v. But that is in the signal path, not a filter cap.


FIlter caps don't have to be polarized - capacitance is capacitance. But a 47uf film cap would be the size of a baseball at least. Electrolytic caps cram a lot of capcitance in a small volume, but e-caps do have polarity and we have to watch for it. SO we need to have polarity because we use e-caps to save space. We don't use e-caps because we need polarity.

REmember, the voltage is already rectified. it will charge a non-polar cap to whatever voltage is in the circuit just the same as it would a polarized one. The difference is - other than size and maybe something like ESR - that the e-cap must have proper polarization, while a film cap could be wired in either way.

If you want an experiment, try this:
Take a completely dischared film cap from the drawer, and connect it across a power source. Maybe a couple hundred volts in an amp somewhere. Disconnect it from the voltage source and measure the voltage now stored in it. Keep track of which end was + and which -. Now discharge the cap, and reverse it and connect it to the same voltage. Now disconnect it and measre the charge stored in it now. it will be the same, except now the other end will be the +. You can do that with a film cap, but don't connect an e-cap backwards, it will blow up.

[tubeswell]

Hey thanks for clearing that up for me Enzo.

[scole]

i was planning to use them here, but your write, they are to small. oh well, i guess i could put a 100uf in there?
http://music-electronics-forum.com/a...1&d=1208410442