Which form of switching do you guys use?

[simon111]

I am just desiging a PCB for my RM clone. And I want to make it true bypass with an indicator. Normally I use a 3PDT switch. But I fancy a change (just for the fun of it)

I have been looking at other forms of bypass i.e. Millenium 2 and such like.

I just wanted to know which forms of true bypass would you recommend for a RM circuit in terms of the lowest audible pop/click being produced.

What true bypass set-ups do you guys prefer or have experienced?

Then I can get on with fisnihing off the PCB!

Cheers guys.

Simon,


PS . Is there a defintiive true bypass technique that anyone swears by as having the least audible click of any method?

[darron]

hey there. there are a few different ways of doing true bypass, but they are all fundamentally the exact same principal. for true bypass there are no electronics, just a switch (unless you are using relays or something, like in an amp where there's a switch that is electrically toggled). so basically you need a dpdt (at least) to do true bypass, or a 3pdt to do true bypass with an LED. you CAN do true bypass with a dpdt using the rats method of switching, but i think a 3pdt is the best option.

here is my method here:
http://www.dazatronyx.com/support/true-bypass-technique.pdf

it's a large pdf file (1MB?), so let it load if you dial up or something

one good thing to get rid of pops is to ground the input of the circuit while the effect is in bypass mode. this serves two purposes, as explained in the article. you could also try a large resistor (1m, 2m2, etc.) from the effect out to ground if you find there's still pop.

i've never had to do this, but you can also ramp the power that the LED uses when you turn it on:
http://www.muzique.com/lab/led.htm

since you are designing the pcb for true bypass, i think it's a really good idea to mount the circuit board off the switch:


i did the layout of the switch in the picture a little differently in that circuit, but all of the connections still do the same thing. if you are deigning a pcb you might want the LED in the middle, or left, or right of the PCB and you can easilly do that.

if you decide to pcb mount the switch, then make the holes perfect and tight enough so that you really have to jam it in there and it won't fall out. then the solder on top of that is just a little added reassurance. traces can lift from the board after all.

darron

[simon111]

Cheers Darron.

One more quick question, this might sound like a daft question but...

Is there any difference between switching the power using the output jack over the input jack (i.e. use a stereo jack for the output)?

Thanks
Simon

[Hambo]

For Millennium 2 I usually add it into the circuit layout I'm making, or if not possible tack it onto a titchy board suspended in the box by the legs of the LED which is epoxy glued into the case.
Either way the layout I use is like this 



C is the control wire which goes to the stomp and the trannies are shown correctly arranged for a 2n7000 and a 2n3904 or similar.

As I understand it, Millennium circuits inherently suffer less switch popping than straight LED switching schemes.. but thats just what I read.. I think.. or maybe dreamt or something. I cant confirm it.

[darron]

i don't think that switching the ground using a stereo jack will make much of a difference at the input or output, and i can't imagine any reason why it would add pop. the standard is to have it switched at the input. i suppose that makes a TINY bit more sense for if you plugged it in to the chain output first and then input, you wouldn't have the effect powered and making noise with a floating input right after plugging the output in. did that make sense? :S

electronics switching is generally silent, but a good 3pdt is very similar, especially when you are at stage volume levels and blending in with the band, or at bedroom levels where the actual phyisical clicking sound overrides the electronic one by far. switches are designed to be as fast as possible to prevent arcing and oxidisation of the contacts.

i prefer the 3pdt ones over most of the x-wing dpdt's for speed and pop. some dpdts seem very crude and slower, especially for sound, but i may jsut be imagining it because the 3pdt has the extra pole and is harder to press.