Footswitch for Boss Katana 50

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Footswitch for Boss Katana 50

Post by Sam Spoons »

I bought a Boss Katana 50 as a backup amp recently when my 18 Watt combo started playing up*. It's a great little amp but the channel switching is a little clumsy.

The problem is that the presets are arranged in two banks of two and a use a two button latching footswitch. To switch patches in a bank, toggle SW1, to switch banks toggle SW2 but to switch from patch A1 to B2 requires both switches to be toggled. I'm trying to design a four button switch to allow selection of each preset by pressing just one FS**. I think could do it using electrically latching relays and momentary switches (my electronics skills are not up to doing it with transistors) but I'm trying to have it completely passive. I think it can be done with 4 DT4P switches but if it can't can somebody with a more logical mind than mine please tell me so I can stop trying :blush:

* I managed to fix the 18 Watt with a little remote hand-holding from Dave so haven't yet used the Kat in anger.

** P1 = FS1 off & FS2 off
P2 = FS1 on & FS2 off
P3 = FS1 off & FS2 on
P4 = FS1 on & FS2 on
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Sam Spoons
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Re: Footswitch for Boss Katana 50

Post by ef37a »

I think you might be on a hiding to nothing here Sam?
You say you need to toggle two latching contacts together but you cannot 'undo' a short with another switch.

Have you worked up a schematic for the existing switch box and measured any supply to it? Might be possible with jfets?

Dave.
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Re: Footswitch for Boss Katana 50

Post by Sam Spoons »

I haven't done that but might get the DVM out later. WRT a passive system I think I've reached the conclusion that it can't be done. So I've found a couple of small relays to have a play with and drawn a circuit that I think will work with 4 x DPDT momentary switches (and I think I have 4 knocking around somewhere). It's just a matter of wiring the relays so that they will latch on when energised and run the latching voltage through the normally-on side of the switches so each switch either/or energises or de-latches one ot both the relays. I'm know it can be done with transistors but designing it is above my pay grade (I studied electrical engineering at college as opposed to electronics, there was a bit of electronics in there but I was too busy playing guitar, drinking beer and trying to get laid to take much notice).

I have a passive, two button switch but the way it works is annoying, it seems as if it was very much an afterthought. SW1 toggles patches 1 and 2, SW2 toggles banks A and B so getting from, say, P1/A to P2/B requires pressing both switches simultaneously.
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Re: Footswitch for Boss Katana 50

Post by ef37a »

You have my email addy Sam so zap me a smudge of the circuit when you have worked it out if you want. J fets are easier to use than bipolars for switching as they are normally 'on' and, if you get the right type, can be turned off with as low as 5V. The gate can be regarded as totally isolated from the circuit being switched.

Beware also of thinking that footswitches are simple single pole jobs. They can be a double pole c/over and that complicates the buggering about with them.

E, very embarrassing G! Fitting a DP/C/O PCB switch 180dgr out of 'rotation' gives some very odd results!

Dave.
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Re: Footswitch for Boss Katana 50

Post by Sam Spoons »

The footswitch jack in the Kat is a TRS, shorting the tip toggles one function, toggling the ring the other (can't remember which way round). I've modded an old FS I made up years ago with two latching switches (it had momentary switches) and it works fine.
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Re: Footswitch for Boss Katana 50

Post by Sam Spoons »

Update on this saga... I have given up on building my own footswitch and bought an XSonic Airstep 'Kat Edition'. It was on offer for $89 direct from XSonic so it only cost me £101.72 (inc carriage) ordered from the US and has many more functions than I could have hoped to manage with my DIY jobbie. I placed the order on 12th June and it arrived this morning, despite it being shipped direct from China and Herpes sending it to the wrong UK depot initially. No hassle and no customs charges so pretty impressed. First impressions are very good, it offers good functionality and was totally plug-n-play. The only minor glitch was that the 3rd party app was only available for iOS15+ and I'm resisting upgrading my ageing iPhone 6S from iOS 14.4 for the moment as I suspect they throttle older devices to make the batteries last longer on newer OS'. On the plus side the Airstep does all the Boss pedal does and also allows the Kat BTS app to edit/control the Kat 50.... Bonus.
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Re: Footswitch for Boss Katana 50

Post by ef37a »

Reeesult Sam!

You could barely have bought the parts for 100 sovs and if you factor in the time to make it a DIY solution would have been much more expensive and not as useful.

I am concerned that people are losing (never had!) electronics skills but there are practicalities to consider.

Dave.
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