#1
Hey guys!

Just looking for a bit of help and advice.
I'm a complete amateur with electronics and know next to nothing.

I've recently bought a synthesiser, which I want to run through my guitar amp and pedalboard and figured a switch for my board should be simple enough to build.

The pedal will have two inputs. A-Guitar, and B-Synthesiser.
An LED for each instrument which will turn on depending on which channel is active and a single output, leading to my pedalboard and guitar amp.
I've bought a small wooden keepsake box which shall be shielded inside with adhesive copper tape. Will that work for shielding.

The plan for my switch has been attached.

But I ask, will the instrument that isnt on still be grounded and safe? Also, how do I add the LEDs into this diagram? How do I ground this or is it already grounded?

Has anybody made anything similar? Can anybody help a complete amateur?

Thanks so much guys!
Nattyb1
Attachments:
2016-01-31 22.46.59.png
#3
I think what he's looking for is a way to switch between two inputs going to one output so he can switch instruments without unplugging one and plugging the other in. An A/B box.

If that's the case this should do, just use the two that are labelled output as the inputs. This will ground out the one not in use. Doing it your way would be fine, but there would be a clicking sound when you switch.



If you want to add in LEDs you'll need a 3PDT footswitch, a power supply (a 9v battery or whatever), and a resistor for each LED. The value of the resistor depends on the power supply, the type of LED, and how bright you want it to be. You could even use one resistor if you want the same value on both. The 3PDT switch is just like the DPDT, but with an extra line so it's a 3x3 grid. You wire it exactly the same and use the extra column to switch between the LEDs.

Here's the same circuit as above but with the LEDs. You could use a 9v battery clip instead of the DC jack if you want to use a battery, or you could do both if you want the option. Note that the side of LED with the longer wire (also usually has a flat spot) is the negative side. In this picture that's also the side the resistor is connected to.




The copper tape should work for shielding, just make sure that if you use multiple pieces of tape that they're all making contact. If the tape has conductive adhesive then that makes it easy, just make sure to overlap a little. If it doesn't have conductive adhesive you can fold a little piece over so that the copper is facing down where it overlaps so there's metal on metal contact and use more tape to hold it down. Or you could try to solder the pieces of tape together but that doesn't sound like fun to me.

Also make sure that the shielding is making contact with the sleeves of the jacks. If the tape goes right up to the edge of the hole the jacks are installed in (just tape over the hole and poke through and trim the excess so it doesn't stick outside the box) then it should make contact when you install them.
Last edited by The4thHorsemen at Jan 31, 2016,
#5
Ah, I just saw the loop, assumed you misunderstood, and didn't actually look at the diagram. Looking at it now I see he could just plug one into the input and the other into the return and it would switch which one gets to the output, and then if he ever wanted to actually use the loop he would have that option. The only thing is it doesn't send either one to ground when it's disengaged so it'll make a popping noise when you switch, or am I wrong on that? I seem to remember reading that but I've never tried it so I'm not sure. It doesn't really matter if the popping doesn't bother you.
#7
Ah yea, could be. I think back when I put a kill switch in one of my guitars I read that you should short the signal to ground instead of just breaking the connection to avoid popping, so I got it in my head that if you just break the connection you'll get a popping noise, but this is also making another connection, so yea idk. I don't really know much about electronics either.
#8
With DPDT and 3PDT switches I think it depends on the make of the switch whether it pops or not. I could be wrong though.
I don't give a shit if you listen to me or not
#9
Great thread

And another great refrerence petty much all that has been said above in one place.

I'm in the throws of making my own loop box but, in keeping with my compact pedal board, it will be compact.

Despite being in a box only 2.25" x 4.25" it will have a Tuner out, two loops and the ability to reverse the loops so I can place my OD/Fuzz loop in front or after my Cry Baby... You know you want one. :-)

Part of the issue with crushing so much into such a small box is accommodating the jack sockets. I had considered just hard wiring in the loop tails to get rid of 4 sockets but have compromised by replacing two of the sockets with one stereo socket and using an I/O lead. Cunning what!
Please note: The above comments are based on my experience, and may represent my perception of that experience. This may not be accurate and, subject to the style of music you play, may be irrelevant or wrong.
#10
Thanks for the help guys!

I'd already ordered a DPDT footswitch for about £5 on ebay, but just placed an order for the 3PDT switch for £1... bizzare. I guess the 3PDTs must me more popular or something.

Using Y leads in the post above is a great idea!
I may get round to making something like that in the future, but for now I think this smaller project is enough to get my toes wet until I become more knowledgeable in pedal design/construction.

I've started painting the enclosure up now, so by the time all the parts have arrived from Hong Kong, it should all be good to go! I'll post a picture once it's done.

Thanks again though, these forums are excellent.
Such a great community!

Even more thanks,
Nathan
#11
Hey! Just wondering as well if LED 1 corresponds to output A. Seems a silly question, but just want to be 100%

Thanks,
Nathan
#12
If you're talking about the A/B box - looking at the diagram it looks like it's reversed. LED 1 would turn on when output B is selected, and vice-versa. Seems the labeling is backwards from what you would think. You could just give yourself enough extra wire going to the LEDs so you have enough slack to move them around without having to resolder them if you get them mixed up. Unless you want a specific LED to be on a certain side.

and yea, 3PDT switches are the most common for pedals since most of the time you'll want that extra pole for the LED.