Help mapping a DPDT switch to a 3PDT please

Started by MrRGecko, October 28, 2017, 01:36:56 PM

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MrRGecko

So I had a footswitch made for my amp by a great company but for whatever reason, it's not actually switching my amp.

The original footswitch is DPDT, but the builder used 3PDT, presumably for the LED.

I was wondering if anybody can tell from the pictures where the error is and tell me how to amend it so that it'll switch my head?

Thanks!

Original;


New Pedal;

GGBB

Welcome.

I see nothing wrong. But we can't really tell if something is wrong unless we know what it is supposed to do. Electrically that is - not just "switch my head." Does the amp expect the switch to make a connection or break a connection? Is it supposed to do it momentarily like sending a signal or permanently (latching)? We need to see a schematic diagram of the switching circuit. Do you have one you can post a link to?
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MrRGecko

Hey man

I can honestly say I don't know the function of the switch aside from it's latching.

I don't have a schematic either but the amp is a Victory Sheriff 44.

Any help would be amazing.

Thanks

Govmnt_Lacky

What is funny is that, in both cases... they wasted a DPDT switch when they could have used a simple SPDT.

In the top picture, the 2 red jumpers across the switch are totally unnecessary. Unless, they wanted redundancy in case one of the switches faulted.
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of 'up to and including my life.'

MrRGecko

So there's no reason why this shouldn't work?

Govmnt_Lacky

#5
It looks like the original switch used a TRS stereo plug.

You need to install a TRS stereo plug into the INPUT 1 on your amp and measure for voltage or Ground on all three. I bet that one of the 3 areas has some voltage on it all the time. I am guessing that when the original pedal was plugged in and the switch was pressed, it passed a voltage from one of the sections (Tip, Ring, or Sleeve) to another section.

When the voltage was NOT passed, one side of the LED was power and the other was grounded causing it to light up. When the voltage IS passed, then the potential was the same on both sides of the LED and it would not light up.

EDIT: A quicker way to figure this out is if you still have the original switching box. Just need to figure out which contacts the Red and White wires go to (Tip, Ring, or Sleeve)
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of 'up to and including my life.'

MrRGecko

That's basically what happens I think. The original doesn't need power but does have an LED.

The original is above, can you figure out which is which from the image?

And yes, it's TRS. Using a TRS on the new switch does nothing for switching the amp.

GGBB

I missed the pic of the original switch entirely.  :icon_redface:

Quote from: Govmnt_Lacky on October 28, 2017, 06:33:13 PM
When the voltage was NOT passed, one side of the LED was power and the other was grounded causing it to light up. When the voltage IS passed, then the potential was the same on both sides of the LED and it would not light up.

Adding to that - the new switch is not that same as the original switch even disregarding the probable TRS problem. At least I think so - but the picture isn't completely clear so I may be mistaken - I think the LED circuit is between switch lugs, meaning it is always connected to the amp's power source, but is turned of by shunting the power source to ground *not* by disconnecting it from power. If I'm right, in the original switch the amp passed current in both switch positions - either directly to ground or through the LED to ground. In the new switch the amp passes current directly to ground in one position but opens the circuit in the other position so that no current flows. In the new switch it appears the LED is powered separately. This could be a problem - but may not be - depending on what the amp is doing with the power it sends to the footswitch, but you should verify the TRS connections first since that is vital.
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Govmnt_Lacky

Quote from: MrRGecko on October 28, 2017, 11:25:01 PM
That's basically what happens I think. The original doesn't need power but does have an LED.

The original is above, can you figure out which is which from the image?

And yes, it's TRS. Using a TRS on the new switch does nothing for switching the amp.

You need to find out where the red and white wires connected to in the original switch. Was it tip and sleeve (like it was built in the new box) or was it sleeve and ring? Ring and tip?

Until you determine this, you will be guessing and that may damage your amp.

You need to either measure voltage with a TRS plug inserved into Input 1 of the amp OR measure the old switch.
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of 'up to and including my life.'

MrRGecko

It was ring and sleeve rather than tip and sleeve. I swapped the cable over and all is good.

Only thing is the LED comes on when the first channel is selected, not the second. Not a deal breaker but is that an easy switch?

GGBB

Quote from: MrRGecko on October 29, 2017, 12:56:11 PM
It was ring and sleeve rather than tip and sleeve. I swapped the cable over and all is good.

Only thing is the LED comes on when the first channel is selected, not the second. Not a deal breaker but is that an easy switch?

See my last post. Simple fix is to move the LED resistor connection to the other side of the switch.
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MrRGecko

Thanks. Do I move it to the red or blue circle?


GGBB

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MrRGecko

Quote from: GGBB on October 29, 2017, 04:07:36 PM
Blue circle.

Doesn't look like it'll fit. I guess I could extend it with a wire?

GGBB

That's fine - just make sure it won't move around and touch anything else - insulate with heatshrink if you have some.
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