Help with SPDT switching

[Keeb]

So I have an SPDT Carling footswitch from when I turned my Wah into true bypass.
Now I would like to use a simple A/B box for a tuner.
Could this be done?
I mean, I have read about SPDT sucks tone but I wouldn't be using the effect (since it won't output anything).
In my mind this would work. Please sort this out for me.
My battery in my meter is dead so I can't measure the swtich but this is right I suppose.

Pic to explain (gotta love paint):


Edit; I just realised that the switch isn't grounded. Would that be a problem?

[blooze_man]

That should work fine.

[R.G.]

So I have an SPDT Carling footswitch from when I turned my Wah into true bypass.
Now I would like to use a simple A/B box for a tuner.
Could this be done?

Yes. that will work, given some caveats.

I mean, I have read about SPDT sucks tone but I wouldn't be using the effect (since it won't output anything).

SPDT switches don't suck tone. It is the consequences of the circuits you have to use with an SPDT that cause tone sucking. The switch itself is just a switch. You won't get tone sucking.

In my mind this would work. Please sort this out for me.
Edit; I just realised that the switch isn't grounded. Would that be a problem?

Not directly. You must put it into a shielded box to prevent hum and RF issues, and the signals must have a ground/shield from one point to the others to prevent hum. But the switch just sits inside the shielded box and does what you have drawn.

[Keeb]

So I have an SPDT Carling footswitch from when I turned my Wah into true bypass.
Now I would like to use a simple A/B box for a tuner.
Could this be done?

Yes. that will work, given some caveats.

I mean, I have read about SPDT sucks tone but I wouldn't be using the effect (since it won't output anything).

SPDT switches don't suck tone. It is the consequences of the circuits you have to use with an SPDT that cause tone sucking. The switch itself is just a switch. You won't get tone sucking.

In my mind this would work. Please sort this out for me.
Edit; I just realised that the switch isn't grounded. Would that be a problem?

Not directly. You must put it into a shielded box to prevent hum and RF issues, and the signals must have a ground/shield from one point to the others to prevent hum. But the switch just sits inside the shielded box and does what you have drawn.

I know I tend to over simplify things in order to understand them but as long as I'm not talking crazy talk! (No circuit -> no suckage!)
Thanks RG for yet another informative post!

Btw, why do we ground a 3PDT switch (the circuit, the jacks are already grounded)?

[jkokura]

Actually, we don't ground the switch. We ground the input of the circuit when it's not in use (usually) and the negative of the LED when it is in use (usually). The switch itself isn't grounding on anything, just the things we attach to the lugs.

Jacob