Tone Cap Question

That is a .01uf ceramic capacitor.

Someone more knowledgeable than I am will have to tell you what the correct factory value for a 74 Fender would be.

 

I like .01uF on a passive bass and find it more useful than the usual .047uF or .1uF.

 

If your meter has a capacitance function, you can read the value directly.
It should be within 20 percent of it's marked value.
M indicates 20% tolerance.

So it should read between .008 and .012 uF.

If you don't have a capacitance mode, you can check that it isn't shorted with the
ohmmeter mode. It should read open. That's about all you can tell with a meter without
a capacitance measuring capability.
If it does read open, you can then simply try it in the circuit. If it seems to be working
as expected, it's likely within tolerance.

 

Do you mean 0.047uF? 0.47uF will almost certainly turn a high impedance signal into mud.

 

Are you saying the .01uF cap is darker sounding than the .047uF cap?

If yes, the .01uF might be a .1uF.

The smaller the value, the brighter the sound; larger value, darker sound.

 

If the ".01uF cap in question" in the pic is darker sounding than a known .047uF cap, it's a .1uF and not a .01uF.

 

103 is the value, its 10, with three 000s pf which is 10,000pf which is .01uf

 

So a 104 is a .1uF cap?

If the cap in the OP's pic is a .01uF, maybe his .047uF cap isn't .047uF? A .047uF should sound darker than a .01uF.

 

Yep a 104 would be a .1uf.

 

I never realized there was a correlation between that number and the value.

Thanks, you taught me something.

 

I just learned this recently as well. I have no clue how the numbers would work on a cap value that wasn't a derivative of 10

 

The derivative of 10, and of all real numbers, is 0.

What do you mean, though?

 

Designations of that type (103) on caps work exactly the same as the resistor
color code, except that it uses the actual digit instead of the color bands.

A resistor of 10,000 ohms would use brown, black, orange, which represents
1, 0, 3 :
1, 0, followed by 3 zeros, or 10,000.

Likewise for a cap, 103 is
1, 0, 3 :
1, 0, followed by 3 zeros, or 10,000.
but in this case the units are pF, not ohms.
To convert pF to uF, divide by 1,000,000. (move the decimal point 6 places to the left)

A 47,000 ohm resistor is marked yellow, violet, orange, which represents
4, 7, 3:
4, 7, followed by 3 zeros, or 47,000
and this is in ohms.

And a .047 uF cap would be marked 473:
4, 7, followed by 3 zeros, or 47,000
and again, this is in units of pF.
Divide by 1,000,000 to get .047 uF.

Other types of caps, might be marked with 3 digits, but the units are nanofarad (nF).
You have to know which system is being used, but they are more or less consistant
for a particular type of cap.

If you ever see a p or an n mixed in with two numbers, the p or n indicates two things:
it indicates that the value is in picofarads or nanofarads respectively, and it also
indicates the position of the decimal point.

2n2 is 2.2 nanofard
4p7 is 4.7 picofarad

 

Great post man. Very informative

 

Megafiddle, thanks for that info.

If I'm not mistaken older caps were marked differently, the abbreviated value (not the numbers). Note the "MFD" instead of "uF" in the pic.

And now for some mojo