What does an ON-OFF-ON switch do?

[slacker]

If you get a 4PDT toggle switch and wire it up like in your schematic for 2 DPDTs that will do what you want with one switch. 4PDTs are relatively expensive compared to DPDTs though.

[Auke Haarsma]

I've found an old thread (2005) by Pushtone where he mentions a solution with a rotary switch, also for two channels. The link to his schematic (which he got from Mr Vex) is dead though. However, he kindly said he will look it up on his pc and post it. In the mean time I've been thinking what this would look like, and I think this will be exactly what I need.

Say I have a rotary switch with 3 poles and 4 positions:

Pole A: connected to 'send channel A'
Pole B: connected to 'send channel B'
Pole C: connected to output of FX

In an overview, with pole and what connection in each position:



 
 
 
 

pole/pos	1	2	3	4
A	FX in	Return Chan A	Return Chan A	FX in
B	Return Chan B	FX in	Return Chan B	FX in
C	Return Chan A	Return Chan B	Bypass	Return Chan A+B

So this results in the following:
In position 1, channel A is routed to the fx input, channel B is bypassing the fx and the output of the fx is routed to channel A.
In position 2, channel B is routed to the fx input, channel A is bypassing the fx and the output of the fx is routed to channel B.
In position 3, channel A is bypassing the fx, channel B is bypassing the fx and the output of the fx is routed to ground (? or whatever is best for the signal)
In position 4, both Chan A and Chan B are routed to the FX IN, the FX out is routed to both Chan A and Chan B.

I'm not sure if Pos 4 will cause strange probs, but it seems like this is exactly what I need.

Am I corerct? Or do I miss something?

[Pushtone]

Here is that switch/routing schem

Its a two bus routing scheme for a multi effect using rotary switches.
Any effect can be assigned to either bus or be bypassed.
Each bus can be bypassed separately with a footswitch.

Haven't built it but simple enough to follow the signal through.
Looks good to me.

Hope this helps pong.

[Pushtone]

The link to his schematic (which he got from Mr Vex) is dead though.

This is kinda funny because I didn't get the schem from Mr. Vex.

What I got was flamed with his infamous 8> emotcon telling me to DIY instead of asking the group to do it for me.
Laced in the flame message was a hint to use a 4P3T rotary.

Talk about a right of passage! Flamed by the master himself.
Everyone's diystompboxes.com experience should include this!

I took Mr Vex's hint and about one hundred pages of notebook paper to figure it out.
I'll always give him credit, but it was me who drew the diagram, schematic if you will.

[Auke Haarsma]

So the credit passes on . Thanks to you for posting this schema and the initial thread and thnx to Vex for giving you a hint

This is kinda funny because I didn't get the schem from Mr. Vex.

What I got was flamed with his infamous 8> emotcon telling me to DIY instead of asking the group to do it for me.
Laced in the flame message was a hint to use a 4P3T rotary.

Funny thing is that I kind of did the same. While awaiting your reply I drew up a schematic (albeit with words, not symbols) which is later confirmed by your post.

Just a small thing, in your schematic there's mention of a 4PDT, which should be 4P3T just as you say in your post.

Anyway, the parts have been ordered (once again...expensive hobby...) and Eagle is running to get my pcb's out!

Thanks for thinking with me here, and if you like, keep an eye on  the progress in my project thread (see sig)

[Auke Haarsma]

I've tried to get some ideas down in Eagle to get schematics and pcbs. What I want is the above mentioned, but with a LED to indicate which channels are active. I hope to use RG's Millenium Bypass for this. I'm unsure however if this is possible at all. This is what I have in mind:



(NB, position 3 and 4 are swapped compared to my previous posting. 4 is now complete bypass, 3 is A+B, seems more logical to me).

Will this work?

[Auke Haarsma]

Tried to breadboard some of it today...man...12 wires from 1 switch...that's a lot! Couldn't get it to work yet, but it's way past midnight, so I catch some sleep first. Better luck tomorrow I hope.

[Auke Haarsma]

well, in my current wiring the 'controls' of the Mil2LED are always connected to the return of CH A or B. Like this it's not going to work... There must be another way...

[Auke Haarsma]

funny thing I came across while breadboarding: put two mil2 bypasses together and wire the control of the first to the 2nd's LED negative lug. Now, this will turn off LED1, but keep LED 2 on. But, when the control (connect to ground) of Bypass2 is used, it will turn off LED 2 but turn on LED 1.

This is nothing spectacular but well, it's funny seeing it happen. Also, when I touch the control with my hand I can have both LEDs lit. I guess my body has a very very large resitance to ground? But still enough gets on to turn on LED 1 and keep LED 2 on at the same time. So, you could have a control (eg a pot) which by turning could light up either LED or both.

Back OT: I guess I have to use 4P3T (and drop the A+B channel option) if I want LED indicators on my channel selection. Can't get it to work with 3P4T's.