Switch to change capacitor

[JPGraphX]

Hi!

I built a pedal and there is a mod for bass, simply change a capacitor!

I would like to put a toggleswitch to be able to go from guitar to bass very fast.

Someone can help me on how to do this? What kind of toggle? How many lugs? How to wire it? I have toggle switch with 2 lugs, is this enough?

Thanks a lot
JP

[lungdart]

Are you trying to change mod your guitar so to have a tone switch to make it more bass-y?

Or do you want a stomp box to plug both your guitar and bass into and switch between the two instruments?

[JPGraphX]

No I built a pedal that can go on bass and guitar, with à capacitor change. But I would like to make it compatible for both. With a switch on my pedal

[GGBB]

You could just try using the bass cap value for guitar - depending on the circuit this won't impact the guitar sound.  Can you give a link to the schematic or mod?  Otherwise, all you need is an SPST switch (or one side of an SPDT).  Two caps in parallel give a capacitance equal to the total of the two cap values, so for the bass cap use a value that is the original bass cap value minus the guitar cap value, rounded up to the next available cap value.  It probably won't matter if you just use the original bass cap value - usually more is better with these types of mods.  Connect one end of the bass cap to one end of the guitar cap, connect the other end of the bass cap to one lug of the switch, and connect the other lug of the switch to the other end of the guitar cap.  The end of the guitar cap that is connected to the bass cap should be the end that has the most direct path to ground (preferably a direct connection or via a resistor to ground).  If you are using a polar cap, make sure you get its polarity correct.

[JPGraphX]

In other words I want a switch on my circuit that go from one capacitor to another.

[JPGraphX]

Schematic : http://www.grindcustomsfx.com/forum/viewtopic.php?f=2&t=180

[JPGraphX]

I got to change C1 for 390nf

[drummer4gc]

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That's my SPDT switch, with three lugs. A is the middle lug, which goes to one spot on the circuit board where a leg from the capacitor should go. The Os are your two caps. One of each of their legs should go to the outside lugs, and the other legs should tie together. From the legs tied together, run a wire to B, the other hole in the circuit board for the cap's other leg.

How's that for an ASCII schematic?

[Hemmel]

I'd used a switch to add a 270nF cap in parallel (100 + 270 = 370nF, close enough)

[JPGraphX]

Hehehe nice ASCII schematics

[GGBB]

Schematic : http://www.grindcustomsfx.com/forum/viewtopic.php?f=2&t=180

On that circuit, I wouldn't bother with the switch, just change C1 to 390n.

[Hemmel]

After an ASCII schem, here's a MSPaint schem

[JPGraphX]

Really?

[JPGraphX]

Nice paint! Thanks guys!

GGCB it wont affect my guitar tone?

[GGBB]

After an ASCII schem, here's a MSPaint schem

That looks like the 270n is always in parallel with C1 and the switch shorts them both - not sure if I am reading the art correctly.

[GGBB]

GGCB it wont affect my guitar tone?

The bass mod is designed to allow more bass frequencies into the circuit via the input cap (C1).  A larger cap means lower frequencies will pass.  Letting lower frequencies in with guitar doesn't do anything since the guitar doesn't have lower frequencies.  This is a simplified explanation though - reality is more complicated.  But since this is a buffer circuit (I think) - the idea is to not change sound at all, so letting lower frequencies in shouldn't be a problem.

EDIT:  I see now it's a Centaur clone - I don't know that pedal well enough to say whether or not the larger input cap would not sound right with guitar.  It's easy to test - just use some jumper wires to add the bass cap in parallel and listen to it.

[JPGraphX]

This is an overdrive and buffer

[lungdart]

That looks like the 270n is always in parallel with C1 and the switch shorts them both - not sure if I am reading the art correctly.

Actually when it's switched to base it would put the 270nF in paralell with C1. When in guitar position, it would connect one side of C1 to a floating terminal, and thus no change. Toggle switch pin outs are usually like this 1-COMMON-2, and the positions are reversed from where the toggle is sitting.

BTW OP, this design would work fine. Another method if you want to be more exact would be to put both capacitors between there positions and common, and solder both positions to where the original cap went. This would literally switch between the two.

[GGBB]

That looks like the 270n is always in parallel with C1 and the switch shorts them both - not sure if I am reading the art correctly.

Actually when it's switched to base it would put the 270nF in paralell with C1. When in guitar position, it would connect one side of C1 to a floating terminal, and thus no change. Toggle switch pin outs are usually like this 1-COMMON-2, and the positions are reversed from where the toggle is sitting.

BTW OP, this design would work fine. Another method if you want to be more exact would be to put both capacitors between there positions and common, and solder both positions to where the original cap went. This would literally switch between the two.

Toggle switch pinouts are usually 1-CENTER-2 - the CENTER lug is not common - on an SPDT ON-ON switch it is connected to EITHER lug 1 or lug 2. 

Here's my reading of the diagram.  Although not stated, the drawing shows the 270n cap connected to the center and right (2) lugs of the switch.  The labeling indicates that those same two lugs connect to either side of C1.  Neither of those connections is broken by the switch.  So that means that C1 and the 270n are permanently wired in parallel.  When the switch is in the bass position, the center and right (2) lugs are connected together, thereby shorting both caps.

[psychedelicfish]

Here's how I would wire it:


The Bass mode cap is shorted out when disengaged, which discharges it so you won't get pops.