Custom Amp Foot Switch With a Twist

[Tone Jones]

A couple of years ago, a local person built me a custom foot switch for my 3 channel amp. It had two foot switches, each with their own 1/4" jack, but what made it pretty trick was it also had a 1/8" mini plug wired to the clean channel foot switch so that every time I switched to the clean channel, it would automatically turn on my Suhr Koji comp due to its ability to be activated via a mini plug. I was hoping to use the same foot switch in the same manner with a newly acquired amp, a Suhr PT15IR, but it isn't working properly. The factory foot switch with the new amp has two foots witches on it with a 1/4" TRS jack.

With some flip-flopping of wires, I was able to get the clean channel foot switch + activating the Koji to work however, when I switch away from the clean channel hitting the same foot switch, it defaults to channel 3 on the PT15 and the other foot switch won't' toggle between channels 2 & 3.

I am unable to have the same person who originally built the foot switch help me and I'm wondering if someone here may know how. Pics below. I appreciate any help anyone can provide.

[idy]

Welcome to the forum.
One approach would be to show us what is inside the footswitch for the new amp; otherwise we need to fid a schematic to see how it works. It is *probably* as simple as your old one, just different.

You could even luck out if all you need to do is adapt the old pair of 1/4 mono jacks to the new TRS. A peek inside would help.

What's in the working new amp footswitch?

[Tone Jones]

Thanks for the welcome! Pics below. FWIW, the factory mentioned the switching is as follows:

CHANNEL 1  - Tip / Sleeve OPEN
CHANNEL 2  - Tip > Sleeve SHORT
CHANNEL 3  - Tip > Ring > Sleeve SHORT

I just don't know how those changes translate to the foot switch I want to use. 

[intripped]

with this little mod, you can use the footswitch with both your amps:
- connecting it as you've always done with your old amp;
- or using the TRS jack of your new amp, plugging it as shown in the image.

[idy]

Maybe that guy knows...
if that isn't it, we know almost enough... the shot of the inside of your custom pedal is dark...
the clean channel switch has two red wires, one a separate wire, the other part of a shielded cable.
there is a black wire to the other switch, and a black and red going to the nearest jack.

but all those wires disappear into darkness and re-emerge...

the "shield" on the cable goes to the middle pin of the switch. Where does the other end of that shield go? Can you clarify what's what or shine some light in there?

[intripped]

Am l "that guy"?
Anyway, I'm almost sure that the shielded cable is going to the 1/8 jack of the Koji pedal.
the single black wires on the two 3PDTs are soldered to the sleeves of the jacks.
then there's the white wire that is the tip of the drive channel, and the red (single) wire that is the tip of the clean channel.

[Tone Jones]

with this little mod, you can use the footswitch with both your amps:
- connecting it as you've always done with your old amp;
- or using the TRS jack of your new amp, plugging it as shown in the image.

I'll give it a try and will report back. Thanks very much!

[Tone Jones]

Maybe that guy knows...
if that isn't it, we know almost enough... the shot of the inside of your custom pedal is dark...
the clean channel switch has two red wires, one a separate wire, the other part of a shielded cable.
there is a black wire to the other switch, and a black and red going to the nearest jack.

but all those wires disappear into darkness and re-emerge...

the "shield" on the cable goes to the middle pin of the switch. Where does the other end of that shield go? Can you clarify what's what or shine some light in there?

Let me know if these work better. Disregard the disconnected white and black wires on the top switch. I was tinkering with them and hadn't re-soldered them back to their original positions. Thanks for your help!

[Tone Jones]

with this little mod, you can use the footswitch with both your amps:
- connecting it as you've always done with your old amp;
- or using the TRS jack of your new amp, plugging it as shown in the image.

I tried your suggestion and we're REALLY close. Here is what happened. When I soldered the new wire in place as you suggested, the amp still does not toggle between channels 2 & 3 when I press the top foot switch. HOWEVER, when I remove the wire from the terminal circled in red, the amp switches to channel 2. I just need to find a way to make that happen when I press the top foot switch but I (clearly) have no knowledge about this stuff. Any ideas?

[intripped]

That's strange...
Have you plugged the trs (stereo) cable in the jack on the left? (looking the top side of the footswitch pedal)

And as a side note: why did you use a shielded cable? A simple wire is required, ...even if it shouldn't be an issue. Just be sure that the shielding little wires are not shorting somewhere around. These shielding wires are not connected to anything, correct?

[Tone Jones]

That's strange...
Have you plugged the trs (stereo) cable in the jack on the left? (looking the top side of the footswitch pedal)

And as a side note: why did you use a shielded cable? A simple wire is required, ...even if it shouldn't be an issue. Just be sure that the shielding little wires are not shorting somewhere around. These shielding wires are not connected to anything, correct?

I did use a TRS cable in the location you suggested, yes. As for the cable, it's just what I had handy. I did confirm it wasn't touching anything else.

That said, what DID work was when I moved the other end of the additional wire you suggested to the terminal on the top switch circled in green. In that location, the foot switch now functions exactly how I wanted. The only thing now though is the LED for that foot switch doesn't turn on when I click it. Ideally, it would illuminate when I selected channel 3 instead of channel 2. Thoughts?

[intripped]

what happens if you try and desolder the white wire and connect it to the terminal circled in green, together with the new (shielded) wire that you've just added?

[Tone Jones]

what happens if you try and desolder the white wire and connect it to the terminal circled in green, together with the new (shielded) wire that you've just added?

Assuming you mean the side of the white wire that is soldered to the switch and not the jack, the LED comes on when the foot switch is pressed but then it doesn't change channels on the amp.

If it makes any difference, I'm not worried about this foot switch being compatible with the previous amp I used it with.

[intripped]

Yes, I meant the side on the switch.

... So, at the moment the only difference between your pedal and Suhr's are the two resistors.
If I'm not wrong (please check this) there aren't resistors or other components on the other side of those two little PCBs in Shur pedal.
If so, then you could try and bypass those 2 resistors in yours and see if it eventually works.

[Tone Jones]

Yes, I meant the side on the switch.

... So, at the moment the only difference between your pedal and Suhr's are the two resistors.
If I'm not wrong (please check this) there aren't resistors or other components on the other side of those two little PCBs in Shur pedal.
If so, then you could try and bypass those 2 resistors in yours and see if it eventually works.

I opened the Suhr factory foot switch and, unless they are integrated within the light pipes, I did not see any resistors. I looked for small surface mount ones on the little PCBs as well.

Before I try removing the resistors in my foot switch, the LED on the lower switch, which selects the clean channel, works properly. I wonder why that one would work okay but not the top LED?

[Tone Jones]

Although I didn't desolder the resistor, does placing the white wire in this photo accomplish the same thing? As you can see, I didn't solder the wire but made sure it had a good mechanical connection. The result is the same as before, the LED now comes on but doesn't switch channels on the amp. When I remove the white wire, the channels change but the LED does not illuminate.

[intripped]

Yes, the new white wire is ok, it does the work as intended... But now I have more doubts and less ideas.

[Tone Jones]

Yes, the new white wire is ok, it does the work as intended... But now I have more doubts and less ideas.

I was afraid you might say that. So weird how close we are with the switch functioning properly but the LED not working and vice versa. I really do appreciate your help and if anything else comes to mind, I'll be monitoring this thread closely.

[PRR]

Is that twisted copper pair soldered to the LED leg?

[Tone Jones]

Is that twisted copper pair soldered to the LED leg?

It isn't but it is pressed against it with light force. I did go ahead and solder directly as well with the same results.