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audiocobbler 6th November 2012 06:12 PM

wiring schematic for DPDT on-on-on toggle selector
Hi folks,

I have a single input shunt resister-based passive preamp volume control to which I want to add two more inputs and the ability to toggle between the three sources. Space is limited, so a toggle will fit better than a rotary selector.

Two questions: first, can someone point me to a decent DPDT toggle that is suitable quality.

Second, I just don't know how to wire up the toggle to include the three sources. I don't need to have a purist single straight through source connection, so avoiding impedance issues with other source components connected.

Thanks for first post here

Mooly 6th November 2012 06:25 PM

So you want three inputs to be selectable to feed into this volume control. A DPDT will give you switching between two inputs not three.

Does it have to be a toggle ? or would a rotary be OK as you could use a 2 pole 3 way switch.

audiocobbler 6th November 2012 07:19 PM

Thanks Mooly, so am I misunderstanding what is possible with a toggle switch only? I thought it was possible to have three selectable connections with an 'on-on-on' switch.

If I have to choose a rotary device, it will need to be small enough to fit in my casing, which was originally designed for one input only.

sreten 6th November 2012 08:02 PM


A "on-on-on" 3 position switch can only switch two stereo sources.

In the middle position you'll get a channel from each of the sources.
Its a specialised switch mainly used for wiring up guitar pickups.

rgds, sreten.

Chris Hornbeck 7th November 2012 01:09 AM

I like to do source switching with three or four ON-OFF-ON double pole center off switches. Jacks connect to the outer terminals and the inner terminals are connected together (and to a volume control). Tape record out and tape play go on the same switch. Easy to do and can be operated in the dark.

All good fortune,

audiocobbler 7th November 2012 02:49 AM

Well, if I go for only two sources to select, and I use a toggle switch, would I be looking at an on-off-on DPDT type?

Chris Hornbeck 7th November 2012 03:31 AM


DUG 7th November 2012 04:07 AM

You only have room for a toggle switch but do you have room elsewhere for some relays?

Use the on-off-on and some relay logic to select one of three inputs.

There is your solution...the rest is details.

Have fun.

Mooly 7th November 2012 06:33 AM

1 Attachment(s)
Here's an example of a small rotary,

AndrewT 7th November 2012 11:15 AM

on-on-on to progressively move along a row of inputs would require some form of latching at each stop position. And return to start at the next on.

The relay wiring for this will have been done, but I suspect the logic is quite complex.
It will be a case of searching until it pops up.

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