Custom channel footswitch?

[matt phelps]

Please excuse my complete electronic ignorance here...I'm just exploring some options and would like to pick your brains on the best way forward.

I have a Marshall AVT100 valvestate amp that comes with a whopping great footswitch to change channels etc. Now what I want to have instead is a much smaller footswitch that could toggle between channels instead and display a coloured LED to indicate which channel was selected. Say green for CLEAN, blue for OD1 and red for OD2 for example - which would mean that I only needed one switch on a custom made pedal.

I've opened up the the current Marshall footpedal and there really isn't a lot in there - jsut some footswitches with a common earth ( I think) and all this wired up to a multi-pin type connecter which runs to the amp.

I would appear to me that it can't be that difficult to work out the pinout for this connector but I'm not sure how I would go about combining the current 3 switch type affair into one 3 position toggle switch instead.

Any advice gratefully received!

[Richard]

Are the switches latching or momentary? I'm sure it can be done but latching switches would probably be easier to figure out. How many buttons are on the switch and what are their functions?

[drlowlow]

I looked for the schematic for that particular amp but without much luck. If I understand correctly though, it is a three channel switching and I would bet that the switching is done through relays that the switches when activated ground out and part of the relay would form a holding path to keep it activated. Of course my thoughts on the matter are just made from how I would design the circuit.

I gave some theorys, Now for where to start and the practicality of it all. if my theory is correct you can disconect the pedel, open it up and bust out the ohm meter and put it accross the two connected points on the individual switches and get a reading with it not pressed and when it is pressed. if you get 0 ohms when the switch is held down only then my idea is correct and I feel safe in saying that you might have some difficulties finding a 3 position N/O switch. adding LEDs to that kind of circuit would be difficult and might entail relays and some kind of phantom power.

If when switched it stays shorted you might have an easier time, but I am not familiar with that kind of foot switch (maybe someone else on here is). If they are locking switches (which I wouldn't bet) then puting leds would be pretty simple if you can find leds that are of an appropriate voltage.

Depending on how far you want to take it, in either scenario a solution could be formed. Like I said the leds on the non locking switches might prove to be alot more involved then you wish to go or maybe you are looking for a challenge. Personally I would prefer being able to switch from any channel to any channel. as for finding the pin out just ohm out from the switches to the pins and write it down.

Good luck.

Benjamin

[godatfoutdigital]

Hey, im new.... signed up just to have my say on this one..

i have the same amp...and foot switch..
and i made my own foot switch for the amp with out the effects on and off button. so being able to make my own, i also know how the thing works.

what you have for your 3 channel buttons is 7 wires...
one ground and 2 other wires for each channel.
take the first channel (clean), when the 1st wire for the clean button is shorted to ground by the MOMONTARY switch, it send the signal up to the amp via the cable to tell it to switch the channel. once the channel is on, the amp then send 5v back down the 2nd wire to power your indicating LED.

basically, 3 wires for each button, one being a common for each...

one wire to ground>changes amp channel>5v back down the 2nd wire to power the corresponding LED.

so....yes you can make the pedal you want....

from what i gather, you want... one pedal and 3 LED's
push pedal once, you have clean and clean indicating LED
push the same pedal a 2nd time, you have OD1 and OD1 indicating LED
push the same pedal a 3rd time, you have OD2 and OD2 indicating LED.

in that case, wire your LED's the same way the marshall foot pedal is wired. so you have ground to each LED and the wire to power the corresponding channel. (note.. you can make you LED's what ever color you want..hahaha)

then, you will have to find a push button switch, with 3 pols, eg, A/B/C..
so the button shorts A to ground, push it again it shorts B to ground, and push it again it shorts C to ground.... (the amp shouldn't care that they stay shorted)(but in the real foot switch marshall provide, they don't remain shorted) ...momentary switch....

but your ABC switch will not be momentary....i hope you get what im trying to say.

and thats it..... i hope i helped you and answered all the ifs and buts, if not, ask again.