If you use an external footswitch in addition to the internal footswitches to switch the AMP1, it should have the following specifications to ensure that it works properly:

1-way or 2-way footswitch

You can connect a normal 2-way footswitch with a stereo jack to the footswitch connection of the AMP1 in addition to the REMOTE1 and the MIDI1 adapter. The two switches of the external foot switch then take over the respective functions of the left and middle internal footswitches of the AMP1 in direct access mode, i.e. CLEAN/OVERDRIVE and BOOST on/off.

A mono footswitch can also be used. This then switches between the clean and overdrive channels, thus taking over the function of the left internal footswitch of the AMP1 in direct access mode.

Switch (no button!)

The special feature of a switch (latching switch) in contrast to a button (momentary switch) is that it latches (on). With a latching footswitch, depressing the switch causes the circuit to close, enabling a specific function assigned to the switch. If the pressure is released from the foot switch, the circuit remains closed. Only by pressing the switch again is the circuit opened again and the assigned function deactivated.

A push button, on the other hand, requires a sustained press to keep the circuit closed and activate the function assigned to the switch. Releasing the switch opens the circuit and disables the function.

Stereo jack (2-way switch) or mono jack (1-way switch)

So that the footswitch switches the AMP1 properly, a 2-way footswitch should have a stereo jack plug, whereas a 1-way footswitch should have a mono jack plug.

If possible, no LEDs

The switching process with footswitches connected to the footswitch socket of the AMP1 is carried out by measuring the voltage at this socket. Footswitches without LEDs always work. A footswitch with an LED without an internal series resistor also works. In the case of footswitches with LEDs, however, the series resistor can be so large that the voltage drop is not sufficient to trigger the switching process.

We know that the following footswitches work reliably:

Lead Foot FS-2	Laney FS2 Mini

Delete

By the way: If you use a 2-way footswitch with LEDs and switch the AMP1's BOOST with the right switch, the footswitch's LED does not tell you if the AMP1's BOOST is on or off... rather, it indicates the switching state of the footswitch. This can match the switching state of the BOOST, but it doesn't have to.

If, for example, "BOOST on" is stored in a preset, the BOOST is activated when this preset is called up via one of the three internal footswitches of the AMP1 - regardless of the switching status of the external footswitch. If the external footswitch is set to OFF at this moment, the footswitch LED will not light up, although the BOOST is active. When the footswitch is pressed, it changes to ON and the LED lights up - but the BOOST of the AMP1 is deactivated. So take care if you're operating a setup like this one!

More articles on the topic:

AMP1 + External Footswitch - How to get all 4 channels?

AMP1 + external footswitch - Why don't all footswitches work with LEDs? ‍ ‍

What are the switching options for the AMP1?‍