Andy40's Madbean Greenbean (tubescreamer)

[Andy40]

This is where it starts. I've proved I can etch a board. Here I just bought one for about 9 bucks.
Instructions, check!

[Andy40]

Okay. Question for the pros. Still getting my head around caps. Greenbean instructions say I need 100n film caps. Does that translate to 0.1uf? If so, for the 120n film cap do I translate that to 0.12uf? Because I've only got 0.1uf caps

[DrNomis_44]

Okay. Question for the pros. Still getting my head around caps. Greenbean instructions say I need 100n film caps. Does that translate to 0.1uf? If so, for the 120n film cap do I translate that to 0.12uf? Because I've only got 0.1uf caps

The shortest answer I can give you to both questions is....yes.

However, I'm going to elaborate on it a bit, a 100nF cap is equivalent to a .1uF cap, and a 120nF cap is equivalent to a .12uF cap, now, if you have a circuit that you want to build that needs a .12uF cap, or a 120nF cap and you only have some .1uF or 100nF caps, you can quite easily substitute a .1uF/100nF for a .12uF/120nF and the circuit should still operate perfectly, you can also substitute a .15uF/150nF cap for the .12uF/120nF too with no problem, most electronic circuits are actually not that critical.


The only thing you need to be mindful of is that the DC working voltage of the substitute cap is equal to, or greater, than the DC working voltage of the originally specified cap, so say the circuit needs a .12uF/50V cap and you happen to have a .15uF/100V cap, it will be perfectly okay to use it as a substitute.

[Andy40]

Thanks Doc! that was a great explanation.

[DrNomis_44]

No worries mate, there's another thing you can do if you're building a circuit and it calls for a cap value that you don't have, you can make up the cap value by putting two smaller value caps in parallel with each other for example, if you need a .1uF cap and you only have two .047uF caps, you can put them in parallel to make one .094uF cap which is close enough in value to a .1uF cap and will work fine.

Or, you can put two .22uF caps in series and you will get a .11uF cap, which is also close enough in value to a .1uF cap and should also work fine.

[mjg]

As Doc says, it won't make much difference to substitute a 100nf for a 120nf.

In this particular case, if it is c5 you are talking about, that one is controlling the tone of the 'Fat' switch. So using a 100nf is fine, you will just not have quite as much change when you flick the Fat switch. You could also try a 150nf or 200nf in there too, to see what tone you like best.

[WeirdBits]

Also, if your multimeter has the appropriate function, test the value of your caps before you use them. That way you start with a known entity and can swap it for another if it's a little too far out of spec and/or not giving the sound you expect.

[DrNomis_44]

Most caps these days usually have a tolerance spec of anything from +/- 10-20% of the marked value on the cap.

[Andy40]

Genius!

[Andy40]

removed post.....I read the schematic...its obvious