Summoning Wiring Gurus (weirdy pls)

[Nickosaurus]

Hey guys,

A friend of mine provided me with this schematic for an a/b footswitch but I'm having trouble interpreting it/thinking about how to apply this in context.



The battery is just for the LED's. The 10M resistors are for anti pop.

Any ideas on how to approach a build for this?

[wokkaboy]

I think Brendan may have built an A/B footswitch so he may be able to help.
Sure when Lozza or Weirdy see the post they can supply you an easy to read diagram

[kimball492]

Try this link has really easy a/b switch diagram
http://www.instructables.com/id/How-to-make-a-AB-box/
Hope it helps
Kimball

[wokkaboy]

nice one Kimball even I think I can follow the instructions and diagram

[WeirdBits]

Nicko, your schematic doesn't seem to be showing at the moment.

This one may be a little too much, but it's versatile: BYOC A/B Bypass Looper.
It can be used as just an A/B switch (using Input with Send A and Send B), or switchable FX loops with bypass, plus LED indicators.

[Nickosaurus]

Yo Bits this link should work for ya

http://cathbard.com/images/temp/ABY.png

[WeirdBits]

Ok, schematic is showing now. It's an ABY box, so you can have either or both outputs on/off using two foot-switches. Red LED is on when output A is active, green LED when output B is active, powered by a 9v battery with optional external DC jack. The 10K resistors set the current for the LEDs (depending on the LEDs) and, as you said, the 10M's smooth out the switching. The linked arrows in the rectangles represent the two poles of the foot-switches, with the origin of the arrows being the two 'common' centre lugs on DPDT foot-switches. Is there specific info you're wanting, or just general guidance on how jam it in a box? Lawry is the real electrickery expert, but I'll help with what I can.

To build it, you'll need:
1 x stereo jack (input with power switching)
2 x mono jacks (output)
2 x DPDT foot-switches
9v battery clip
2.1mm DC jack
2 x 10M resistors
2 x 10K resistors (value depends on the LEDs you use)
1 x green LED
1 x red LED
Optional mounts/bezels for LEDs (or just super glue them in)
Hook-up wire
Some type of box, preferably metal, able to withstand enthusiastic stomping.

Nothing else is really needed as it's all just direct wiring between the jacks, switches and components.

A lot of the info in the PDF I linked in the earlier post is generally relevant and may be of use.

[Nickosaurus]

The main thing that was confusing me was the dpdt switches. The ones I have seen in real life have all been 3 a side but these in the schem look different.

Do I count lug 1 - 4 on the left column and 5-6 on the right column?

What do the divots mean coming out of the input/output/battery - do they indicate hot/ground?

Which type of DPDT switches do I need? on/off/on? How do you know?

If I do use a metal box how do you make a ground in it?

This is my first time reading schematics so I will be asking a few questions. I thought this would be a cool project though and I've always wanted to learn to read schems.

Cheers!

[WeirdBits]

Foot-switches used in pedals are usually either DPDT (2 pole 2 position, having 2 sets of 3 lugs) or 3PDT (3 pole 2 position, having 3 sets of 3 lugs). They are On/On latching switches, that is each 'click' changes from one 'on' state to the other (as opposed to momentary switches). The 'divots' on the schematic represent the 'tip' contact on the jacks.

I'll try to draw up some stuff later today that should help to guide you through understanding the schematic and building it.

[Brendan]

Nick - maybe look here?
http://www.learningaboutelectronics....tch-wiring.php - I know you are looking at a footswitch, but this should explain what the diagram is and linkage to pins on a DPDT footswitch.

I have built a straight A/B box - http://www.buildyourownguitar.com.au...ead.php?t=2481 pretty straightforward and I put links to the diagram. Will differ as it's an A/B - not A/B/Y - that's the next project. Also has the advantage of requiring an output cable to turn on - so no drain on the batteries .