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-   -   How do footswitches work? (http://www.ultimate-guitar.com/forum/showthread.php?t=1567934)

saint22 10-14-2012 09:55 PM

How do footswitches work?
 
I'm talking about simple channel switching footswitches. I assume they control some sort of relay? I'd like to add a couple of LEDs to my footswitch. I was thinking about trying to power them from the voltage across the switch but according to my multimeter there isn't any, whether the switch is open or closed.

Am I misunderstanding how they work?

roshjosh 10-14-2012 10:00 PM

The power that moves through a footswitch (if any) is not going to be able to power an LED. It's like adding an LED into your guitar circuitry.

Kevin Saale 10-14-2012 10:02 PM

I'm almost positive the footswitches with LEDs have that in mind when the switching circuit is designed so that there is enough voltage to the pedal to light the LEDs.

Which means in your case, you'd have to get the power from somewhere else likely.

saint22 10-14-2012 10:10 PM

Oh well. I've got a few extra spot on my one spot, I'll just add a 9v jack I guess.

saint22 10-14-2012 10:14 PM

Wait, so does the guitar signal actually flow through the footswitch?

end_citizen 10-14-2012 10:26 PM

Quote:
Originally Posted by saint22
Wait, so does the guitar signal actually flow through the footswitch?


No. Not ever. What is your amp? I can give you a general idea of how it works if I knew the specific amp.

saint22 10-14-2012 10:30 PM

Peavey Classic 30. I'm using the vox 2 button switch. I didn't think the signal went through the footswitch, but I was confused by the guy saying it was similar to trying to power an via by a guitar signal. Is it just that it's a millivolt level signal?

end_citizen 10-14-2012 10:41 PM

Quote:
Originally Posted by saint22
Peavey Classic 30. I'm using the vox 2 button switch. I didn't think the signal went through the footswitch, but I was confused by the guy saying it was similar to trying to power an via by a guitar signal. Is it just that it's a millivolt level signal?


I'm honestly not going to concern myself with the guitar signal statement.

How the footswitch works in a Peavey Classic 30:

The footswitch jack consists of several connections, but we will concern ourselves with the two the pertain to the actual switching: The tip and the shield. The shield is grounded at all times. When the footswitch is activated, the tip gets shorted out to the shield and becomes grounded as well.

This grounding completes a circuit in a relay inside the amp. The relay is just an electrically activated switch. This switch puts part of the circuit into an active state that gives a boosting effect.

No signals pass through the footswitch. It is only a ground being completed.

saint22 10-14-2012 10:48 PM

But then there must be a voltage when the switch is open. Is the issue just that it's an extremely small voltage?

end_citizen 10-14-2012 10:54 PM

Quote:
Originally Posted by saint22
But then there must be a voltage when the switch is open. Is the issue just that it's an extremely small voltage?


A voltage happens when a current flows through a resistance. There is a difference in a potential, but that doesn't mean there is useable voltage there.

gypsyblues7373 10-14-2012 11:19 PM

There's a guy on evil bay that sells metal LED footswitches for the Classic 30. I got one for a Delta Blues (which is pretty much just a Classic 30 with tremolo) that I bought used that had no footswitch. Works like a charm, seems pretty sturdy. Unless you just want the experience of making one yourself.

seljer 10-15-2012 03:44 AM

An amp can be designed to have enough current run through the footswitch to enable a indicator LED without any other power. Though it entirely depends on what the designer did in his design.

The surest thing to do is just use dual pole switches with a seperate power source for lighting the LEDs

Rossmillertarn! 10-15-2012 08:46 AM

Guys, the LEDs on footswitches are powered from the amp itself. the amp sends a 9v current through to the footswitch just for this purpose.



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