Footswitch Help

[eldanko]

I have a Hughes and Kettner Rotosphere that I love, and I recently put together a remote footswitch so I could leave it back at the amp and run it in the fx loop. The instructions for wiring the footswitch (as found in the manual) are as follows:

"Stereo jack for external Bypass and Slow-Fast switch. (tip = Bypass; ring = Slow-Fast switching)"

So I wired up a box containing two DPDT switches - one that would connect the tip to ground/sleeve, and another that would connect the ring to ground/sleeve.



This worked fine. When I hit the switches, the corresponding LEDs on the unit would activate and the unit responded accordingly. I wondered if I might be able to add indicator LEDs to the box, so I measured the plug coming from the unit and sure enough found some voltage on it. So... I added LEDs like this:



Both LEDs work. When actuated, the LEDs on the unit respond as well.

The weird part: The left switch (which turns the unit on/off) functions properly. The right switch (which toggles between slow and fast speeds) does not. The LED on the unit changes state, but the speed doesn't actually change like it did before I added the LED.

Any clue why one side would work and the other wouldn't? They're wired identically.

[rullywowr]

It's probably a logic thing. Having the LED in
series will produce a voltage drop around 2.1v.   This extra consumption may be screwing with the switching circuit.

Looks like you actually used two spdt switches. It would be a better idea to use two Dpdt and an auxiliary power source. You could use a battery or even phantom power it with another conductor in a custom cable.

[eldanko]

It's probably a logic thing. Having the LED in
series will produce a voltage drop around 2.1v.   This extra consumption may be screwing with the switching circuit.

Looks like you actually used two spdt switches. It would be a better idea to use two Dpdt and an auxiliary power source. You could use a battery or even phantom power it with another conductor in a custom cable.

Thanks for the reply mate. The voltage drop thing occurred to me and I tried several different LEDs to see if any of them produced a lesser drop that would fix things, but had no luck.

I considered the external source/battery thing, but I'd prefer not to go that route... Based on the reading I've done in various forums, other people have successfully used footswitches with LEDs (old amp footswitches, etc.). I guess I'm just not grasping why one side is working fine and the other is not...

[eldanko]

Allegedly.. this can be done:

http://www.rockblockswitches.com/index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=152&virtuemart_category_id=18