I have been using the BOSS FS-6 as my external footswitch for the past ten years, and I recently picked up the smaller BOSS FS-7 to see how it compares. They look like near-identical products separated only by size, but there is one difference between them that should decide your purchase before anything else does — and it is not the one most people reach for first.
What an external footswitch actually does
Put simply, an external footswitch is a triggering device. It turns something on and it turns something off. The classic use is channel switching on a traditional valve amplifier — one press takes you from the clean channel to the overdriven channel and back again. Anything with a footswitch input can be driven this way, which is why these switches turn up on so many pedalboards.
Both are dual footswitches in a compact box
The clever part of both the FS-6 and the FS-7 is that they are dual footswitch designs in a genuinely compact form factor. You get two switches, A and B, in one enclosure.
Better still, you can determine the end destination of each footswitch individually. Send both A and B to the same device if that is what you need, or split them — footswitch A to your amplifier, footswitch B to a second amplifier or to a multi-effects unit to toggle something like a tuner. Two independent jobs from one small box.
Choose between momentary and latch
Both pedals carry additional controls that change the state the footswitch operates in: momentary or latch. Which one you pick determines how the switch responds to the device it is triggering.
Latch works like a light switch. Press once and it stays on. Press a second time and it goes off. That is what you want for channel switching, where the change needs to hold until you decide otherwise.
Momentary is a press-and-hold command. The effect is triggered for as long as your foot is down, and the moment you release the switch it stops. Useful when you want something to exist only while you are asking for it.
The power supply is the real decision
Beyond the obvious difference in size, power is the huge factor to weigh up before you buy. The two pedals are powered in completely different ways, and that single difference is what should point you at one or the other.
How the FS-6 is powered
The FS-6 runs exclusively off an internal battery, so you need a 9-volt battery in it to work at all. Connecting your lead is what powers the unit up — it triggers the on command and the two red lights illuminate as you click the switches in. Disconnect the cable and the FS-6 turns itself off.
That leads to a real problem. If you leave the cable connected on your pedalboard after a late night and forget to unplug it, the FS-6 carries on drawing power. There is a good chance the next time you reach for it the battery has run flat, which gets frustrating quickly if you use it often.
Tip: If you go FS-6, get into the habit of pulling the cable at the end of every session. The plug is the power switch — treating it as anything else is how you arrive at a gig with a dead footswitch.
How the FS-7 is powered
The FS-7 runs off an external power supply instead. If you are running a pedalboard like the BOSS BCB-90X with an integrated power supply, you can daisy chain the FS-7 to your power brick along with everything else. Turn the plug on at the wall and the whole board — external footswitch included — boots up together.
It means you can leave the FS-7 connected at all times. For working musicians who use this equipment frequently and would rather not think about batteries, charging or recharging, that is the better solution.
When the FS-6 is still the right answer
There is one scenario where the FS-6 wins outright, and it is busking. If you are running a battery-operated looper like the BOSS RC-500 into a battery-operated amp and you have no power outlet anywhere, an external power supply is no use to you. The FS-6 is battery operated too, so it is the only one of the two that will work. Your rig has no mains power, so your footswitch cannot need any either.
The FS-7 is smaller than you think
The FS-6 is a bit of a brute next to the FS-7. What surprised me on unboxing the FS-7 was that it is about half the size I had pictured in my head — a genuinely elegant solution.
That opens something up. Because it is so small, you can run multiple FS-7s in close proximity to one another and get a lot of external footswitch capability into a very small surface area. In roughly the footprint of a single FS-6 you could get close to three FS-7s side by side, which is six external footswitches instead of two. If your setup is growing, that is worth thinking about.
My verdict
Ignore the size for a moment and answer one question: does your rig have mains power?
If it does — a pedalboard, a power brick, a stage, a rehearsal room — buy the FS-7. It lives on your board permanently, boots with everything else, never needs a battery, and takes up less room while doing it. If you want more than two switches later, you can add another and still use less space than one FS-6.
If your rig runs on batteries and there is no wall socket in the picture — busking with a battery looper and a battery amp — the FS-6 is not a compromise, it is the only one that works.
For most people reading this, that means the FS-7. After ten years on the FS-6, it is the one I would point you at first.