Pots and capacitors question

[Jimryan]

Mornin all,

Two questions,

What's the difference between capacitors? Eg oil in paper, orange drops, etc

And what's the difference between 500k and 250k pots?

Cheers,

James

[Ou7shined]

Caps : Tonally..... none.
Different values however offer different shelving options for the frequency point at which the highs are rolled off.

250k vs 500k pot : slightly different response out of the sweep. Worth experimenting with pertinent to your own needs.

Edited September 26, 2013 by Ou7shined

[KiOgon]

PIO is a very old way of making caps - therefore they must sound old school - right? Oh & they cost a lot so they must be good
Orange drops is usually a 'poly drop' cap, totally more modern manufacturing method therefore must be good for modern rock music

The higher value pots, bigger numbers will let more frequencies through, giving a 'brighter' sound.

[Jimryan]

Awesome, cheers guys, just what I wanted

[iiipopes]

Um, I must comment as to one post that may be inadvertently misleading. Yes, in an in-line high pass circuit, the larger value of the capacitor, the more frequency range that is allowed through. But in a typical bass guitar tone circuit, the larger value of the cap, the more highs that are shunted to ground, and the darker the resulting tone through the jack to the amplifier. There is no practical difference as to the tone of a capacitor in a typical bass guitar circuit as far as the type of capacitor. So all the hype about supposed differences tonally in paper-in-oil, ceramics, polythenes, tantalums, mylars, bumble bees, and orange drops, just due to the mode of construction, are all hype. What matters is consistency of the value in microfarads. Voltage rating of the capacitor doesn't really matter, either, as we are talking millivolts. Personally, I do tend to use orange drops, but not because of their hype. I prefer a .033 tone capacitor to allow more mids in the mix when I roll off my tone knob, and it is easier and less expensive to get one of those in that value than some other makes, and Sprague is a reputable company that has good consistency and quality control, so I know if I want a .033, that's what I'm getting, with less variance than with some other lesser quality companies. I can understand that, if a person has a vintage instrument, and for the sake of retaining vintage value, a replacement of the same make, model, value and voltage rating capacitor that was original to the instrument is desireable.

Edited September 26, 2013 by iiipopes

[flyfisher]

This is an interesting read . . . although maybe not if you've just spent a lot of dosh on an antique paper in oil capacitor.
http://www.aqdi.com/tonecap.htm

[Mr. Foxen]

[quote name='flyfisher' timestamp='1380229264' post='2222682']
This is an interesting read . . . although maybe not if you've just spent a lot of dosh on an antique paper in oil capacitor.
[url="http://www.aqdi.com/tonecap.htm"]http://www.aqdi.com/tonecap.htm[/url]
[/quote]

Dodge bit at the end:

[quote]
[font="Arial,Helvetica"][font="Arial,Helvetica"][font="Arial,Helvetica"][font="Arial,Helvetica"]Inside the metal chassis of a tube amplifier, this factor is immaterial, since the chassis provides shielding. In a guitar, this might be a problem. However, I have shielded the cavities of all my instruments with copper foil, haven't you? [/font][/font][/font][/font]
[/quote]

Inside the chassis of an amplifier is a whole bunch of noise sources, you have to lay it out so that they are not near stuff that can pick up noise, so being inside a chassis is pretty irrelevant when the noise sources are also inside it. Also, seems copper foil isn't ideal shielding, even though it looks nice because there is some noise effects if can have that I don't fully understand, skin effects, and eddy currents due to high electrical permeability, that can give noise (think its related to why you grounds amps to the same part of the chassis in amps, because there can be a voltage difference between two points, plus capacitive coupling. Basically, shielding paint is better because it is resistive, but conducts enough for shielding. I'm gonna check with the guy when I see him online.

[Jimryan]

Ok then, so, if I want my passive circuit to have a nice, vintage, bassy and slightly middy sound when the tone is rolled off, what do you guys suggest? Just stick with a .033 as mentioned of any other contenders?

Cheers guys

[SparkBird]

TRy this to try tones out quickly.
Get several cap values .
disconnect the cap , noting where it connected .
Attach (solder or even crocodile clip) a cable to each of points noted
A/B several different values .1 to .015 to find the one you like .
There really isn't a right one, only ones you do or don't like .

I would disagree with the that the material the cap is made of doesn't make a difference to the sound , i can hear it in blind tests in amps and guitars, never tried it on bass though .
But i've got to admit whole the thing is cork sniffing , you end up peering up your own arse . Even on a guitar i only hear the difference straining my ears in a dark room (which is silly really) or the studio .

Trying values is a valuable excercise though .
Oh and on the 'vintage' 'replica' pio caps , watch out , a lot are vintage in appearence only , not inside .

[iiipopes]

Since no electronic component has its exact nominal value, the perceived differences in tone could be as much as the manufacturing tolerance difference in the value of the capacitor as the type, and probably more likely, as the slightly different actual value of the capacitors compared to their nominal values would result in a different rolloff frequency.

Edited October 15, 2013 by iiipopes