KTG-1 footswitch wiring

[fyzygy]

I have a KTG-1 King Tone Generator tube preamp, which has two footswitch connectors: a phone jack (for simple channel select) and a 5-pin DIN connector (for channel select, boost for either/both channels, and lead crunch).

In the absence of the original SD programmable footswitch, I wish to build my own as a substitute. The original had jumper switches (I have no idea what for, exactly) but I am simply hoping to wire four footswitches, each with LED indicator, to the 5-pin DIN connector at back of KTG-1.

If i read the schematic rightly, there are 6 wires leading to the DIN socket. Looking from the rear of the unit, and reading clockwise from 12 o'clock, we have (I think): black (ground), purple (channel select), yellow, green, white, and red (12v+). I'm guessing that it's simply a matter of linking/shorting each of the respective wires to ground, to activate/deactivate each function. I'm also guessing that the 12 volts should *not* be connected to ground under any circumstances, and that it is used to power the activity LEDs on the original programmable footswitch -- in which case, resistors in the circuit would be necessary (as 12v+ is too hot for a LED).

Is anybody able to confirm that I'm on the right track? Does anybody know if a custom multi-footswitch will work without the original "programmable" jumper switch block? Or -- even better -- does anybody happen to have a copy of the schematic for the SD programmable footswitch?

Thanks for reading my post.

 

[fyzygy]

Re: KTG-1 footswitch wiring

In answer to my own post ... I picked up a cheap 2nd-hand Randall 4-button footswitch, (RG75-E is printed on the inside PCB). It has a 6-pin DIN connector and cable. I rewired one end of the cable for 5-pin DIN, pretty much as outlined above, leaving last pin (red wire of KTG-1, possibly 12v+) unconnected (there is also a surplus 6th wire in the Randall cable). Fortunately, everything seems to be working: for the KTG-1 I now have remotely switchable channel select/lead crunch/clean boost/lead boost, with LED status indicators working as well. For some reason, the last 2 LEDs are dim compared with the first two.

Next will probably be a couple of KTG-1 mods: the "crunch mod" indicated on some paperwork from Seymour Duncan Research; and also a transformer upgrade (the only thing I dislike about this preamp is the mechanical hum emanating from the power transformer).

All in good time.

 

[jwprice9048]

Re: KTG-1 footswitch wiring

Could you post the wiring diagram of your mods to the RG75-E. I'm suffering from the same problem, no available footswitch.

Thanks.

 

[jwprice9048]

Re: KTG-1 footswitch wiring

Another note on the footswitch issue. After much web surfing it seems that the Behringer FS 114 is a potential match for use with this unit. It has a 5 pin DIN output and four switches. Just need to verify that the wiring is proper.