Build Your Own Clone Message Board

Hey guys!
Can I put 2 seperate SPDT On-OFF-On toggle switches in the diode section of my Classic OD?

I know I can take the 2 diodes out that are on the PCB now and then wire a switch to the eyelets meant for one of the diodes. Like in this post here:http://www.buildyourownclone.com/board/viewtopic.php?f=12&t=1537.

So can I wire a second switch into the other diode space as well?

I thought about just doing the DPDT On-On-On option but I like the idea of having 4 different clipping options instead of 3, as well as the "diode lift" option that the SPDT On-Off-On switch gives you. Also if it works with 2 SPDT switches then it would be cool so see what the different clipping options on each switch sound like layered on top of each other.

Hope this questions makes sense, if not sorry to sound like such a noob, but I am a noob and I thought I should bring this to you guys first, before taking my pedal apart. Any help would be greatly appreciated.

THANKS!

The short answer is "yes", but there are some qualifiers that go with it.

1. First of all, I would recommend against the use of SPDT switches for this service, since you end up with diodes "hanging" from the lugs, unless you're using perfboard or something similar to attach them to. That's a fragile situation, and it's easy to break off a diode lead with a bit too much bending. Instead, go with DPDT switches, solder your diodes across the end pairs of lugs, and run your PCB connections from the middle lugs. You can still use an on-off-on style of switch, to be able to get a "diode-lift" at the off position. In fact, that's what you should use anyway, because....
   
   
2. ....with parallel diode paths, the lowest forward voltage threshold "wins". In other words, lets say you had two of these switches hooked up and had a pair of LED's selected on one switch and a pair of 1N34A germanium diodes selected on the other. Your signal will NOT sound like a mixture of the two clipping modes, because that's not how diode clipping works. Think of your signal as a river flowing from source (your guitar) to outlet (your amp). These diodes could be thought of as side channels with an overflow dam that can be used to draw down the level of the river. The switches would basically function as locks, opening or closing the flow to the diode dam. A germanium diode has a very low forward voltage threshold (~0.3V typically), so it's a low dam. An LED has a high FVT (>2.0V), so it's a high dam. So think about what would happen if both locks (switches) are open--all the water is going to go over the low dam, because it's the path of least resistance. And that's exactly what would happen--all your signal clipping would be through the 1N34A's, because of their low FVT. For this reason, you need to be able to shut off your switches completely, otherwise the open lowest FVT pathway will always do all the clipping. Using on-off-on DPDT switches will accomplish this.

Have you decided what diode combinations you want to use for your four different clipper choices?

Thanks Duhvoodooman

I will use the DPDT On-OFF-On switch as you suggested. I found some at radioshack with the Contacts Rated: 3A @ 125VAC and 1A @250VAC are these ok to use?... The switches I get from SmallBear are 2A @ 250VAC and 5A @ 125VAC.

As for the clipping options,
Switch 1: symmetrical/asymmetrical.
Switch 2:LEDs/Germanium

I will use two 1N4148 for the symmetrical clipping (current clipping in the BYOC classic OD). I plan on using a PCB I got from radioshack (suggested by you, THANKS!) and loading it up with some sockets so I can try different diodes and LED combos for the rest of the options, this way I can keep tinkering easily until I find what works best for me.

Thanks! You have been a big help.

If you are going to have that many clipping options, dont forget to try a set of 1n4001's, which are my favorite clipping diodes.

Sure, those have way more voltage and current capacity than you will need.

I will try the 1N4001s Thanks BradWorld! Do you prefer symmetric or asymmetric when using them?

Hey Duhvoodooman, It seemed high to me, but it was the only ones they had in the store. I just wanted to make sure it wasn't going to effect the pedal or sound in a negative way. I still don't know much about pedal building but thanks to the people on this forum I have been able to find the answers to almost all my questions.

Thanks!

I would try it booth ways. In my 250+ kit I use 3 diodes. In my fuzz builds I only use 2 diodes. So give it a test with some aligator clip jumpers or something and see how it works. Also beware that they usually have way thicker leads, and you may have a hard time getting them into sockets. That is always the rub with those types of diodes.

Will do BradWorld, Thanks again!