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Capacitors...what are the differences between one and the other?

cnltb

cnltb

May 28, 2005
18,748
5,900
#1
Hi all, the title says it , really.
I am looking for tone caps and am wondering where the differences lie when looking at different makes and models.
Sprague seem popular, right? What makes these stand out apart from the colour etc...who makes the best ones as far as you are concerned.
I am looking for one to go into a 51' style P bass.
Thanks very much for reading and for any insight you may be able and willing to share!
:)
 
#2
best advise I can think of is to make a test board. You put the caps into a piece of cardboard or other stiff non conductive material and use some gator clips that are wired into your bass and clip between the different caps and pick the one you like the best with your bass set up.

I am sure there is a youtube vid somewhere :)

enjoy the tone quest!

Todd :)
 
#3
The brand, size and whatnot doesn't matter in your bass. They won't be under any heavy load.

The only thing that will matter is the tolerance. More expensive caps seem to have better tolerance figures.

The only things you should worry about are the uF and tolerance.

Have fun!
 
#4
Capacitors vary greatly in details that matter a lot in some applications but for bass guitar tone caps, pretty much anything will work. You will find that ceramic caps are avoided like the plague in audio work in general because audio frequencies require capacitor values large enough that ceramic caps must use non-linear dielectric materials to supply them. This is death to the THD of a hi-fi amplifier, but in a guitar it really doesn't matter. It's a gentle, tube-like distortion. So any capacitor that supplies the value you want will be fine.

Ken
 
#5
cnltb said:
Hi all, the title says it , really.
I am looking for tone caps and am wondering where the differences lie when looking at different makes and models.
Sprague seem popular, right? What makes these stand out apart from the colour etc...who makes the best ones as far as you are concerned.
I am looking for one to go into a 51' style P bass.
Thanks very much for reading and for any insight you may be able and willing to share!
:)
Click to expand...

Sprague are usually electrolytic, used for power supply filtering and cathode bypass in amplifiers, not tone caps in instruments.
 
#6
1958Bassman said:
Sprague are usually electrolytic, used for power supply filtering and cathode bypass in amplifiers, not tone caps in instruments.
Click to expand...

Vishay/Sprague is a brand. They make orange drops which are polypropylene film caps and not electrolytic caps. They make a lot of different caps.

Invalid Link Removed
 
#7
Thanks all.
so is there something to all the talk about 'orange drops'?
These are the onyl one I quite often hear specifically mentioned when this subject is addressed.:)
 
#9
Electricblue said:
The brand, size and whatnot doesn't matter in your bass. The only things you should worry about are the uF and tolerance.

Have fun!
Click to expand...

+1. In fact, you don't even need to sweat the tolerance, really.

Tone caps aren't in the signal path. They bleed treble frequencies to ground. The signal going to your amp doesn't go through the cap at all. People will rant and rave about the "proper" tone cap, but all that matters is the value in uF of the cap. Don't lose any sleep (or big money for "magic" capacitors) over it.
 
#11
bigalbass said:
+1 I fail to see why people need a 400 volt cap for a bass tone control.
Click to expand...

You don't. people see big caps in vintage instruments, but that's because Fender also used those caps in amps, and pretty much that's how caps were back then.

The real joke is the paper in oil caps. You even see YouTube videos will people demoing caps and everyone swears that they sound different. But they don't. Unfortunately the guy doing the video saw it fit to show a caption of which cap is which, so then conformation bias sets in and people think they hear a difference.

The only thing that will sound different is the value of the cap and the value of the tone pot.
 
#13
Lo-E said:
+1. In fact, you don't even need to sweat the tolerance, really.

Tone caps aren't in the signal path. They bleed treble frequencies to ground. The signal going to your amp doesn't go through the cap at all. People will rant and rave about the "proper" tone cap, but all that matters is the value in uF of the cap. Don't lose any sleep (or big money for "magic" capacitors) over it.
Click to expand...

Even though the signal doesn't actually go _through_ the cap, the cap works as a low pass filter and that low pass filter is in the signal path. What you remove is just as important as what you retain (by definition).

In any case, when it comes to tone caps in string instruments... use whatever. I used the one that came in the bag with a Fender pot.
 
#14
shadewind said:
Even though the signal doesn't actually go _through_ the cap, the cap works as a low pass filter and that low pass filter is in the signal path. What you remove is just as important as what you retain (by definition).
Click to expand...

Sure... but it's a filter. Past a certain frequency, the signal is shorted to ground. The cap could be made out of whatever you like, it still won't affect the signal.
 
#15
A lot of good info has already been passed on, but I'll add my 2 cents worth any way.

You can calculate the lowest frequency of roll off by this equation: frequency = 1 / (2 x PI x R x C) where PI = 3.14159, R = Resistance of your pot, and C is the value of the capacitor. As you can see when R goes down the roll off frequency goes up. That means more highs in the signal. So when R goes to more or less 0 then you get the signal through with very little attenuation.

Tolerance only matters if you replace the pot with a fixed resistor and are building several thousand guitars and want them all to sound the same. Otherwise you'll tweak the pot to what sounds good and the value of R and C will be whatever they will be.

Then you get the whole discussion of orange drop and such. First up color makes absolutely no difference (unless it doesn't match your shoes but that's another discussion). There are a few basic types: Ceramic, Film, and Electrolytic. There are others but probably not terribly relevant to this discussion. Within those types there are a variety of materials.

For ceramic, the more stable and precise the capacitance the lower the values that are obtainable. The one thing you need to know about them for audio work is that they are subject to the piezoelectric effect. That means they will physically expand and contract at the frequency of the current passing through them. With a cap with leads on it, the leads will absorb just about all of that. If it's mounted directly to a PCB, then it is subject to cracking at low frequencies. And if the currents are high enough and the environment quiet enough, you can hear them audibly "singing". Note that this is incredibly unlikely to occur inside your bass.

For film, you have mostly polyester, polypropylene, and poly-carbonate. Polyester is the most popular, most readily available and probably cheapest. This would be the material of choice for most audio work. Polypropylene gets used in applications like filtering on AC power lines. These capacitors will actually "self-heal" meaning if there's a short in them, that spot will locally burn open without damaging anything around it and the cap will keep on operating with a very slight drop in capacitance. While this sounds cool, it is of precious little value to audio work where the voltages and currents are much much lower. The poly-carbonate are used in specialized high current applications.

And lastly there's Electrolytic. There are many different materials used for dielectrics. I won't go into them because the vast majority of them are polarized and not suited for audio work. They work great on DC signals but either won't work or can even be damaged by AC.

So go check out a leaded metallized polyester cap of the value need. Best bang for you buck in this application. Most come in voltage values that make it not worth discussing for tone caps. Just get the smallest one you can for the capacitance you need. Vishay bought Sprague many years ago and is a large manufacturer world wide for film caps. Panasonic is another large, well known and well respected manufacturer. There are many others but you couldn't go wrong with either of these guys.
 
#16
Sure... but it's a filter. Past a certain frequency, the signal is shorted to ground. The cap could be made out of whatever you like, it still won't affect the signal.
Click to expand...

Technically everything that touches your signal affects it. The only question is by how much.

If you get a capacitor that has too much capacitance or is damaged such that it "leaks" current to ground then your signal will be weakened and more susceptible to noise and just won't be able to get loud.

If you get a capacitor that has too little capacitance or is damaged such that it has a very high internal resistance then your tone controls won't work and tweaking the pot will have little if any affect on your tone.

So while there are many choices that will yield more or less the same result, it does matter to some degree what you choose. Can you audibly tell the difference between a brand new Sprague orange drop or a brand new Radioshack green box of the same value? No. I know there are those who swear you can but the variations in them caused by the shear act of soldering them into place are as significant or more significant than the variation from capacitors of the same value and material from two different manufacturers.
 
#19
play4sanity said:
You can calculate the lowest frequency of roll off by this equation: frequency = 1 / (2 x PI x R x C) where PI = 3.14159, R = Resistance of your pot, and C is the value of the capacitor. As you can see when R goes down the roll off frequency goes up. That means more highs in the signal. So when R goes to more or less 0 then you get the signal through with very little attenuation.
Click to expand...

You need to calculate the impedance of the pickup into that. The higher the impedance the more of an affect the cap has, since it's forming a resonant low pass filter. It's really not an RC filter, as there is no series R in the circuit.

And this is only when the tone pot is at zero. When it's at 10 the impedance of the cap at the frequency range of the bass is such that it's more like a wire, and the resistance of the pot takes over. As you get to 5 and below the cap starts to roll off the highs.
 
#20
jeffbonny said:
So what does make a difference? Why? What tonal characteristics and variations can you typically expect from them?
Click to expand...

The value of the cap (capacitance), the impedance of the rest of the circuit, the value of the tone pot (resistance) and the curve of the tone pot.

Assuming all the parts are functioning correctly, these are the factors that will affect your tone.

Why? Because these (capacitance and Impedance) are the factors that determine the frequency at which a filter operates.

Changing any of these values will change either the roll-off frequency of the filter or the curve at which the roll-off occurs.

The total impedance of the circuit is often overlooked (Good catch, SDG Lutherie!) and inclues not only the pickup(s) and volume pot(s), but also any additional tone controls, the position of any and all control pots at any given time and, to some degree, the impedance of the instrument cord and the input impedance of whatever device you are plugging into.

BUT - what will really make a difference you are likely to notice are simply the value of the cap and the value and curve of the tone pot. Those are the big three.
 

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