3PDT and LED questions...

[azrael]

I'm trying to gain a better understanding of what it is I'm doing, haha.

Why is the LED here connected to ground...
http://www.generalguitargadgets.com/diagrams/tonebender_m2p_lo_pp.gif

When this one is connected to the power source?
http://www.generalguitargadgets.com/diagrams/switch_lo_3pdt_ig_dcjack.gif

I assume it has something to do with the fact that the Tonebender is positive ground...?

[darron]

In both cases the LED must eventually be connected to both the positive power supply and ground, it's just a matter of which one ends up going back through the switch. The limiting resistor can go on either the ground or positive side.

The 3PDT switch in those is also used to ground the input of the circuit when it is in bypass mode (LED is off) to prevent oscillations and other unwanted effects. So you are completely right when you say one switches positive and one negative because one circuit has a positive ground. As long as the circuit is broken for the LED though it doesn't matter one way or the other.

[MikeH]

I tend to wire mine with the anode (neg, ground side) on the switch.  For a couple reasons.  One, there is usuall already a ground connection at the switch, because I pretty much always ground my fx input in bypass.  The other, and this might just be voodoo, but because of potential signal coupling through the switch, I'd rather have the ground on the switch, rather than V+ because it would be potentially less noisy.  Yeah, that's probably voodoo.

[petemoore]

  I put the pulldowns on the switch in a 'triangle'.
  The leads solder really nice, and further solderings [such as circuit swapping] require less joints to be redone, and using the resistor leads as a connection point to resolder on keeps the heat and un-neatness away from the switch.
  ...in this kind of 'wrapper' the jacks/Gnd.s/Led/pulldowns all stay with the box during a circuit swap.

[azrael]

^Could you explain that method a bit more?


thanks folks, that makes sense!


Another question: If I wanted to skip the battery snap, could I just connect the RING connection to where the battery's positive connection went?

[MikeH]

Another question: If I wanted to skip the battery snap, could I just connect the RING connection to where the battery's positive connection went?

No, just leave it the battery snap off entirely, and leave it's connections open. 

[azrael]

really? alright, that works. thanks. could use some extra space in the 1590 enclosure i'm doing haha.