4P3T Toggle switchs for LCR (summing mixer)

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Alistair

Well-known member
Joined
Jul 22, 2010
Messages
58
Hi all,

I'm intending to make a summing mixer based on the NYD schem that a lot of people have used, with a few extra little things added.
I was just wondering if anyone had found a decent supplier for 4P3T switches for the LCR selection?  I haven't managed to find any for less than about $15, which is really going to add up across 16 channels (around $240! :-[ ).  When you compare that to being able to find a bag of 50 4P3T rotary switches for $60, it's a pretty serious difference!

 
http://www.futurlec.com/SwRotary.shtml


Do be prepared to wait 2 weeks + for delivery.
 
Thanks,
I've found quite a few suppliers of rotary switches, I'm actually looking for toggle switches.  I don't think I'm going to find a cheap supply though unfortunately.

Thanks though!
 
Alistair said:
Thanks,
I've found quite a few suppliers of rotary switches, I'm actually looking for toggle switches.  I don't think I'm going to find a cheap supply though unfortunately.

Thanks though!
Click to expand...

if you find em cheap enough they will probably suck.... at least that's my experience. I'd go with rotaries as suggested.

greetings,

Thomas
 
Alistair said:
Hi all,

I'm intending to make a summing mixer based on the NYD schem that a lot of people have used, with a few extra little things added.
I was just wondering if anyone had found a decent supplier for 4P3T switches for the LCR selection?  I haven't managed to find any for less than about $15, which is really going to add up across 16 channels (around $240! :-[ ).  When you compare that to being able to find a bag of 50 4P3T rotary switches for $60, it's a pretty serious difference!
Click to expand...
You may investigate slide switches. They are much cheaper, but they need a rectangular cutout. Another idea is to use a SP3T driving a CMOS switch (DG308/411 type).
 
Alistair, how are you going to wire the 4P3T switches?  Do you have a schematic in mind? I can't seem to find the one you're working from.

I'm asking because, unlike a rotary switch, a 3T toggle doesn't actually have 3 positions.  The middle is of course just "off". 
Are you just shorting out the other side when you select left or right only?  And then, how are you dealing with 3dB down (or your preference) for both channels on, or are you not bothering?
Sorry for the questions.  It's just that I haven't had much coffee yet :) and I can't seem to visualise how it's done!  I  think abbey road d enfer's suggestion above makes sense though.

Thanks.
 
Thanks for the reply guys.

CMOS switching would be cool, but at the moment I'm trying to keep it passive and unpowered.  The only reason for hunting down toggles instead of rotary switches is based on my quick calculations, it's going to be very hard to fit 16 rotaries in a 1ru unit.

4p3t On-Off-On switches are quite easy to find, but I found a few 4p3t On-On-On switches in the bowels of a Mouser catalogue the other day.  $15 each though....
I've never seen an On-On-On switch in person, but I presume the pin out would have to be similar to a rotary. 
 
(and now I'm looking for that toggle switch on Mouser and I can't find it...was it all part of my imagination!)  :eek:
 
Thanks for that.  I checked out the C&K site and actually found the info on the 4p3t on-on-on switch, so I didn't imagine it! 
Interesting to see the pin out though. 
Looking at it, I think it should be possible to wire as a balanced LCR switch.  I'll try and explain, but words are messy so if anyone is keen let me know and I'll draw a diagram.

If L +/- were wired to pins 11 and 5, and R +/- to pins 8 and 2, that would place the L/R outputs down the centre row of pins.

From here, you could wire + ins to 9 and 10, and - to 3 and 4.  Wire pin 1 to pin 7, and 6 to 12 to ensure no open pins.

When switched one way, 11 connects with 10 and 5 with 4, giving you signal on the left.  Hard the other way and 8 meets 9 and 2 connects with 3, so you've got signal out the right.

When in the centre position, all of these connections would happen simultaneously. 

If anyone wants the reference, the document is "7000 catalog pages" off this link- http://www.ck-components.com/7000/toggle,10598,en.html
Switch number is 7411
 
By the way, this is now a purely intellectual matter. At $15 per switch ( :eek:) I'll be going with rotary switches regardless.

 
Thanks for the links guys, I didn't know those switches existed in that form.  Only others I've seen that were toggle and did this were the telephone 'lever' type switches from Switchcraft and others.  Also the GPO levers used on older Neve consul stuff.    They are much more expensive than even $15 though. 
 
Alistair said:
Thanks for that.  I checked out the C&K site and actually found the info on the 4p3t on-on-on switch, so I didn't imagine it! 
Interesting to see the pin out though. 
Looking at it, I think it should be possible to wire as a balanced LCR switch.  I'll try and explain, but words are messy so if anyone is keen let me know and I'll draw a diagram.

If L +/- were wired to pins 11 and 5, and R +/- to pins 8 and 2, that would place the L/R outputs down the centre row of pins.

From here, you could wire + ins to 9 and 10, and - to 3 and 4.  Wire pin 1 to pin 7, and 6 to 12 to ensure no open pins.

When switched one way, 11 connects with 10 and 5 with 4, giving you signal on the left.  Hard the other way and 8 meets 9 and 2 connects with 3, so you've got signal out the right.

When in the centre position, all of these connections would happen simultaneously. 

If anyone wants the reference, the document is "7000 catalog pages" off this link- http://www.ck-components.com/7000/toggle,10598,en.html
Switch number is 7411
Click to expand...

Rather than start a new thread I thought I'd just dig this up. I'm laying out a board for a summing mixer and found some cheap 4P3T toggles to use for the pan controls and plan to have them wired up as described above. What I can't figure out is a way to insert the resistors needed to attenuate the signal when it's in center position because center position just connects both left and right at once rather than being a separate connection.
Attached is a schematic.
 

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