Home Forums GuitarPCB Build Support Diode switching using DPDT Wiring Board Mod

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  • #14017
    Jeff
    Participant

    I’d like to add a mod to the Superdrive 70s PCB board whereby I can have a toggle (or footswitch) to switch between silicone and germanium diodes.  Simple I know, but I’m not 100% clear on what’s going on in the Build Guide where it shows a photo, but no description of the “Optional mod.”  For instance, on the board itself there are 4 clipping diodes and the guide has the 4 silicone ones shown mounted on the main PCB board.  …but on the DPDT Wiring Board, there are only 3 germanium diodes and what looks like two red LEDs.  I’m not sure how the A/B circuit works in conjunction with the 4 on-board diodes and how I should install the germanium diodes on the DPDT board (shouldn’t there be 4?).  Anyone have any specifics or can point me in the right direction?

    #14018
    wilkie1
    Moderator

    If you use diodes on the main Super 70’s board, you would not use the optional DPDT board connected to A and B.

    If you DO wish to use an optional DPDT wiring board, you would not place diodes on the main board.  You would use any combination of diodes and/or LEDs you want on the DPDT wiring board and connect it to A and B.  The photo shown on the Build Document is just an example of what you may want to try.  The key word for the DPDT board in the diagram is “OPTIONAL”.

    The build guides on this site offer suggestions on diode clipping options.  I hope this helps.

    #14019
    Jeff
    Participant

    Got it, that’s what I was wondering since the circuit didn’t make sense with diodes on the board and also on the switch.  …and thanks for your quick reply.   One more little detail if you dont’ mind.  Will there be a noticeable difference if I use only 3 diodes as shown on the Optional DPDT switching board instead of the 4 diodes that would be stock on the PCB board?

    #14020
    wilkie1
    Moderator

    The specific type of diode/LED will give different tones.  Different combinations of diodes i.e. 2>2<, 2>1<, 3>2<, etc. will sound different.  That’s why many folks will use different switching combinations. Have fun!

    #14022
    Cybercow
    Moderator

    Jeff – using only 3 clipping diodes is an often used configuration. It set up what pedal builders refer to as “Asymmetrical Clipping”. There are some great articles diode clipping here: Electronics Tutorials, here: DIYStompBoxes, and here: AMZ

    Those articles explain clipping quite comprehensively and certainly better than I. I suspect you may enjoy experimenting with a few different configurations before you set it in solder permanently.

    All the best.

    #14024
    Jeff
    Participant

    Thank you for the tips and article links.  That’s exactly what I needed.  I definitely will do some experimenting with different combinations.  I just wanted to narrow the experimenting down to what has worked for others and why four diodes vs three vs two, etc.

    Again, my thanks.

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