Rotary switches with more than 6 positions of 2 poles

Started by Mark Hammer, September 24, 2012, 10:36:06 AM

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Mark Hammer

I wanted to stick a whole bunch of 2 and 3-knob fuzz and overdrive circuits, currently exisiting as little perf and PC boards with wires and pots hanging off them, on a rack panel, and pick the one I want with a 2-pole chicken-headed rotary knob that lets me true-bypass the circuits.  I can probably fit 18-20 on a 2U panel with enough room for legending and unimpeded knob access.  I suppose I'm fine with a 2-pole 6-position, and 3 groups of 6, if push comes to shove, but was curious about whether there are perhaps other switches that might accommodate more positions, like 8 or more.

Are there moderately priced (as opposed the the $40 monstrosities I've seen so far) rotary switches out there that will do >6 positions for two poles?

Fender3D

"NOT FLAMMABLE" is not a challenge

Electron Tornado

#2
Check out Lorlin:  http://www.lorlin.co.uk/

I used one of their switches that had 12 positions, but could be adjusted to fewer positions. I don't recall where I actually purchased the switch, however.

Come to think of it, I'm pretty sure they make at least a 3 pole switch, though I don't know how many positions you can get. I used a 3 pole switch on a dipthonizer.
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R.G.

And now you're ready for something really electronic...  :icon_biggrin:

Will 8 positions do you? If it will, you want to see the programmable footswitch system at Geofex, figure 7, and make the one-of-eight switch selector. Then use one CD4053 per "channel" to do the bypassing. You could use a relay per channel too, but that's about $2.50 - $3.50 per channel for the relays. CD4053 is about $0.50 each.

Yes, it's much more of a PITA to have to make your own switch, but it's cheaper - and I think it's expandable to N switches by paralleling more latch chips.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

Mark Hammer

#4
Quote from: Fender3D on September 24, 2012, 11:22:55 AM
Hi Mark,
I'm afraid these http://it.mouser.com/ProductDetail/Electroswitch/C1D0212N-A/?qs=sGAEpiMZZMvNbjZ2WlReYkj4TnT6O8G1JLX8M6bZiJk%3d are the cheapest you'll find...
What about a single pole switch and a bunch of relays?
Well, that not only complicates what sits behind the panel, but ultimately raises the price up to what the costlier multi-position switches run for.  My preference, for simplicity and cost is to stick with rotaries, no matter how elegant other switchng arrangements and technologies might be.

The Lorlin site seems to max out at 6 positions for a non-coded 2-pole switch.  I don't need more than 2 poles.  One of the nice things about a rotary switch and chicken-head knob is that a status indicator light isn't necessary to show what circuit is selected.  I'll just use rub-on transfers to run a line on the panel from the volume pot of each circuit to a big position-indicator dot at a switch position.

My goal here is to simplify rather than get exotic.  One in and one out jack.  One panel instead of multiple boxes or modules.  A multi-position switch means I get one circuit of my choosing at a time, with nothing complicating the path between the circuit and the in and out jacks.  I'm guessing that I will be relegated to three sets of 6.  Not what I'd call a hardship, though, I suppose.

The application is really more studio-focussed than gigging-focussed.  With each group-of-6 having its own in and out jack, that also means one can run things in series in "interesting" ways.  The possibilities are not infinite, since anything within a group of 6 cannot be used concurrently with anything else in that group.  But again, the permutations and combinations of 18 different clipping circuits, usable in any sequence, singly or in groups of 2 or 3, is not exactly what I'd call limiting.

Correct me if the math is wrong, but that gives me 18 individual choices of one circuit, 36*3*2=216 ways of running two circuits in series, whether A->B or B->A, and 1296*6=7776 ways of running 3 circuits (out of the 18) in series.  So, with over 8000 possibilities (and that doesn't include parallel processing!), I think my distortion universe is pretty decently populated.  The hard part will be deciding what 18 circuits represent distinct elements that deserve their own spot, and suppressing the urge to add toggles and extra controls to 2 and 3-knobbers.  There are a LOT of little boards sitting in the big box-o-circuits.

If it WAS something intended for on-the-fly switching, I'd seriously consider the CMOS+relay options, but there is no such application intended.  In this instance, simple low-tech works just fine, and doesn't constrain me.

stm

Mark, a simple solution to select between 12 different circuits is using two independent 1x12 rotary switches.  You'd have to use one for the input selction and one for the output selection.  Only drawback is you have to be aware that both switches must be set to the same position, otherwise you won't get any sound.

davent

#6
 Hit up the audio HIFI specialists, lots of sometimes reasonable options. I just received  one of the connex branded switches (2 x 4) and it's very solid with a nice distinct, satisfying clunk when switching between positions.

2 x 12 http://www.partsconnexion.com/CONNEX-75577.html

2 x 24 http://www.partsconnexion.com/CONNEX-75572.html

2 x 46! http://www.partsconnexion.com/SEIDEN-74751.html

dave
"If you always do what you always did- you always get what you always got." - Unknown
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Mark Hammer

Thanks for the suggestion, dave.  It seems that anything with 2 poles that goes beyond 6 positions is likely to be found in audiophile places, at audiophile prices.  Now, $16USD(+shipping) for a 24-position switch isn't terrible, compared to some of the $40-50 units I saw listed at Mouser.  But when 6-position units can be gotten for $3 and less (and I have about a half dozen of those already in my parts drawers), it's still pricey enough to warrant a pass.  I do appreciate the thought, though.

.Mike

Mark,

Check Ebay.

I have a saved search for multiple pole rotary switches, hoping to find a 2p8t for a tap tempo tremolo. I see 2p11t all the time, like...

2P11T 2 pole 11 position ceramic switch qty 3
- $9.99

And here is a 2p12t for $9: Link

Here is my Ebay search: link

Mike
If you're not doing it for yourself, it's not DIY. ;)

My effects site: Just one more build... | My website: America's Debate.

davent

Using .Mike's ebay search, the first switch up looks identical to what Parstconnexion sell as their house brand.. but at the far east cost savings. Would just take a lot longer to arrive. Again really impressed by the quality of the  connex switch i received.

http://www.ebay.com/itm/2P12T-2Gates-12-Steps-Rotary-Switch-Volume-Control-Selector-DIY-/250949846200?pt=US_Amplifier_Parts_Components&hash=item3a6dc6c4b8
"If you always do what you always did- you always get what you always got." - Unknown
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Devius

i saw a 2 pole 12 position pot at the electronics store today. I'll check the brand next time i'm there.


Dom D

Could you use two switches with less options and then be able to stack? Just thinking out loud.

PRR

> max out at 6 positions for a non-coded 2-pole switch

The most common (thus cheap) switch chassis has 12 pins around the rim (and 1 to 4 in the center).

Therefore you can buy:

1P12T
2P6T
3P4T
4P3T
6P2T

Anything else costs more than a buck; typically MUCH more, unless you can score bulk surplus or eBay dregs.

That 2Pole 23 Step for ten clams is a good score; but if bought through proper channels it would be many times the price. (Might need to go that way if you were planning to sell a Product and needed for-sure parts supply.)

> then be able to stack?

The "good old" switches were built to stack. But you needed a long center shaft, plus all the little bits to gang the wafers. Once upon a time a good parts store would have a drawer with all the parts to build-your-own. They did not sell well then, and I have not seen such in decades.

The one-buck (or $3) switches are highly simplified and not stackable any easy way. The wafer is staked to the frame and the shaft barely reaches the wafer. Sure, a clever fabricator could do something, but the time/effort amounts to paying the $20-$70 for the few remaining multi-wafer switches.

There's also 1915 style. Put brass studs in a circle on a board. Drill for a shaft, mount brass fingers on shaft. Aside from being more craft-work than electronics, plain brass (tin, chrome, iron) contacts are troublesome.
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Mark Hammer

First, thanks to all for the many good tips on other switches.

In the end, I decided to be satisfied with the 6-position units.  As Paul/PRR notes, once you move from 12 pins to >12, there is a big leap in purchase price.  And, I have to confess as well, an equally big leap in the ease of accurately legending a panel so that knob positions line up with markings!

In the end, a threesome of 6 different circuits will provide me with all the possibilities I need....and probably all I will have room for, too!

Simon Owen

You could have bunch them into banks of 6 effects and wrap another 6 way 2 pole around them to select the banks.

R.G.

Quote from: Mark Hammer on September 28, 2012, 09:08:48 AM
In the end, I decided to be satisfied with the 6-position units.  As Paul/PRR notes, once you move from 12 pins to >12, there is a big leap in purchase price.  And, I have to confess as well, an equally big leap in the ease of accurately legending a panel so that knob positions line up with markings!

In the end, a threesome of 6 different circuits will provide me with all the possibilities I need....and probably all I will have room for, too!
I tend to always try to think of how to make any electronic need that has more than one of anything be both modular and expandable in small steps.

That's one reason I like the one-of-N switches and the CD4053. You take your lumps with sets of up-to-8 CMOS latches, but those are about $1.00 each for the latch. After that, you can put in one momentary switch for selection and one CD4053 for each new channel of switching. It grows gracefully.  And the ability to have one momentary switch per channel is nice - not limited to the legends around one shaft.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

armdnrdy

#18
Hey Mark,

You mentioned the difficulty in accurately legending a panel. I don't know if you use visio, but if you do there's a freeware tool called visio radial elements tool that can be utilized to make tick marks. I've had success with a just bit of trial and error printing to check alignment. Here's a youtube tutorial. http://www.youtube.com/watch?v=2cUHCKbNF38

And here is a delay pedal template that I designed using visio and the radial elements tool.   

http://www.aronnelson.com/gallery/main.php/v/diyuser/AD-900+Template.jpg.html



I just designed a new fuzz circuit! It almost sounds a little different than the last fifty fuzz circuits I designed! ;)

Mark Hammer

My approach is definitely lower tech.  Each set of 6 circuits will be arranged in two subsets of 3 horizontal rows, with volume pots closest to the "inside"  So, if you can imagine 6 two-knob fuzzes laid out like so:
gain-volume ---------- volume-gain
gain-volume ---------- volume-gain
gain-volume ---SW--- volume-gain

...where the chicken head points upwards, and rub-on lines join the volume knob to the location of the pointer.  As for aligning the pointer with the graphics, I simply fasten the switch and knob how I want, and use a fine-tip marker to put a tiny dot where the pointer will be for each position.  Then, I remove the knob and switch, and rub on a bigger black dot transfer over the marker dot.  Clear laquer then goes over all the indicator dots, lines, and legending.  The uniform arrangement of controls minimizes the need for extensive legending.  The first group-o-six is as above, and the second (and possibly third) goes:
gain-tone-volume ---------- volume-tone-gain
gain-tone-volume ---------- volume-tone-gain
gain-tone-volume ---SW--- volume-tone-gain

So, a single label at the top of each column of knobs.  No fancy graphics, just an indication of what circuit one is using, and what function one is adjusting.  I don't care if the tone knob is for a Tonebender MkIII, a Big Muff, a Foxx Tone Machine or a Bluesbreaker; it's still a tone knob.