ceramic disc capacitors

[bakerlite]

so i am trying to figure out a code: .003k  to be precise

i cant seem to figure it out with no end of google searching -

thr way i thought you read them was first significant o. then second significant number and then multiplier

but how can .0 and 0 be multiplied?!!

i am a bit lost...

[sluckey]

That particular cap is probably 0.003µF.

[Tiny_Daddy]

The K may be a tolerance code, maybe 10%.

[bakerlite]

thanks guys - it says .003 in the schematic aswell with no discriptor of value like nf/pf/uf

alot of the disc caps in this amp are in bad shape - brittle leads and soft. i dont know where it was stored in its life but alot of the caps in general are soft and cracking with a waxy residue over them.

I want to do a stock rebuild minus the hum balance - at least on the trem channell (135w twin UL) i may experiment with the notmal channell to get it voiced for bass guitar down the line but thats a while away yet.

at the moment i am creating a visio layout of this amp catalogueing all the parts needed as i go and not puttting anything in until i reference it in the schematic - so far its all stock

as a novice to visio its a slow slow process!

thanks again

[HotBluePlates]

They got lazy when placing the labels.

The "250" and "500" caps imply "pF" because you could fit 250uF or 500uF caps at the voltages listed on that board. The "10pF" has a unit label because you could conceivably confuse it with 10uF.

Likewise, the ".01" and ".003" caps are probably in uF. ".01pF" or ".003pF" are absurd values, and you almost never see a cap marked in nanofarads.

Putting the "k" designator for tolerance is just rediculous. Unless the guy making the drawing had caps in hand marked that way, so he copied what was in front of him. With caps, people tend to buy whatever makes them feel good, regardless of spec; therefore, I doubt most folks would adhere to his recommendations.

[stingray_65]

It's getting harder to find 1KV ceramics these days

Do beware when ordering that they are indeed 1 KV, most I find these days are 50V.

[Tom_Hull]

http://www.electronicsteacher.com/capacitor-chart.php

http://www.justradios.com/orderform.html

yahooo,,,,,,,,,, search engine works finds different things

[bakerlite]

Is there another option to ceramics alltogether?

like micas or something? or is the ceramic disc chosen because of its size ratio to voltage rating?

ie; a 1kv mica might be a little on the large side!

[HotBluePlates]

Any cap with the same capacitance. You don't really need a 1kV rating either; 630v is most you'll need, and 400v is likely good enough in most positions. The layout is simply showing what the original amp used.