Caps - trying to get all values in the series

[atferrari]

With the intention to develope some 4-pole audio filters, I tried, just tried, to get in advance, a selection of multi layer caps going from pF values until 1 uF, following the E12 series.

To my surprise, the sole store carrying them locally, was able to supply just 12 values from the 50 I asked! The reasons: "they are not commercial so we dont carry them" or "Farnell has not them in the list".

Am I being candid in expecting to get all the values for the series, not being Sony or Samsung to order 50 million units of each one?

Expecting to produce very small size PCBs I face the necessity to put 3 or 4 caps in parallel to reach the design value. I always considered that a poor practice and don't like to start measuring caps, one by one to get a decent parallel for each value.

Surprised & frustrated.

Comments, ideas anyone? (I live in Buenos Aires - Argentina

 

[Nigel Goodwin]

Unlike resistors, it's rare for capacitors to be stocked (or perhaps even manufactured?) in all the E12 values - so I'm not at all surprised!.

 

[atferrari]

You seem to be on line, Nigel, Good afternoon.

OK, duly noted.

What do you suggest then? Paralleling caps, right?

 

[Nigel Goodwin]

You seem to be on line, Nigel, Good afternoon.

OK, duly noted.

What do you suggest then? Paralleling caps, right?

Yes, that's about all you can do - or, try and use standard value capacitors, and adjust the resistors instead.

 

[atferrari]

Yes, it seems more reasonable. After all resistors are MUCH easier to get in any flavor.

Gracias.

 

[Hero999]

Try RS components, they stock a wide range of capacitor kits.
**broken link removed**

 

[audioguru]

Multilayer caps? Ceramic? Use metalized poly film caps for low distortion.

Measuring caps? Metalized poly film caps come standard in 5% tolerance.

You aren't ordering 10,000 custom value caps so put the ones you find in parallel.

 

[RODALCO]

Most electrolytic caps are only supplied in the 1.0 - 2.2 and 4.7 µF (or multiples) values (Tolerance about ± 20%)
You are lucky to get the odd 1.5 - 3.3 or 6.8 value.

It seem to be that only the small polyester type and ceramic caps have the odd extra values like 1.2 - 1.8 - 2.7 - 3.9 etc. which are not available for the other types of capacitors.
It has possibly something to do with the process of manufacturing the caps or simply supply and demand for odd values and the common E3 values suffice for most applications.