Ampeg AFP 4 footswitch (where to get it or alternative)

Easy to build one if you are into DIY. The schematic is here, you do not need to use the PCB.

https://supportloudtech.netx.net/file/asset/7131/original/attachment

 

If you can’t find a used one, you can ask a local electronics repair person to build it for you.

 

Another option is two two button switches. The four needs two cords anyway.

I also had an SVT-5 that was missing the original footswitch. I just put it on my ebay watch list and got one after a few weeks.

 

Yes - they are commonly available. If you can grab a couple used, maybe can resell them when you find a four button unit.

 

You wouldn't "link" the pedals together - there are two inputs on the rear panel of the amp - each input is for controlling two different functions. One is for switching between the clean/high gain channels and channel combine and the other is for octave and mute. Each two button footswitch can plug into either one of the inputs (just like the 4 button model would - which also requires 2 trs cords).

 

https://www.guitarcenter.com/Used/Ampeg/SVT-5-PRO-Bass-Amp-Head.gc