Passive source selector - rotary switch
Feb 16, 2011 at 11:48 AM Thread Starter Post #1 of 27

technetium

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Hi Guys
 
I need a bit of help here. I need a source selector for 3 sources, the source signal is unbalanced. I simply try to connect my squeezebox and tv, to the same pair of active speakers. I want to go passive as I dont need to switch that often between the sources, so having a relay psu drawing power all the time seems as not so good idea.
 
I have seached a fair bit inhere on the topic, but with no final answer to my question. I need a high quality rotary switch that can do this, without sharing the ground (Is this not the best idea?).
 
I have found these:
Alps: http://cgi.ebay.com/2pc-Rotary-Switch-2-Wafers-8-Poles-3-Positions-SRRN234-/130338645455?pt=LH_DefaultDomain_0&hash=item1e58c9e5cf
 
Elma: http://cgi.ebay.com/ELMA-BV17250-1206-A-BCD-ROTARY-SWITCH-2X16POS-9PIN-/180199734747?pt=LH_DefaultDomain_0&hash=item29f4bdbddb
 
I know about the goldpoint etc but that is to expensive, then rarther go relay.
 
I live in the EU, so I prefer buying of ebay as most US sellers either charge a insane amount in shipping or dont ship at all.
 
Will those switches work or do I need to pick some others? I need to wafers, as it is stereo, but how many pin? And how to connect the rca jack? Anyone got a drawing :)
 
 
Feb 16, 2011 at 4:56 PM Post #4 of 27

Pars

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Let's see... if you need 2 decks for stereo (L and R), then you need at least one more for ground. If you want to switch each channel's ground separately, then you would need 4 total. Most commercial equipment has the grounds connected together internally, so unless you are using some balanced gear, switching the grounds together (i.e., 3 decks) is more than sufficient. Going to 4 will limit your switch selection also, as well as the number of positions (how may inputs you can switch).
 
As for wiring it, you will need to look at the datasheet for the particular switch you choose. Normally, there are one or more central contacts where you would wire the output to, then outer contacts that correspond with which position the switch is in, which would be wired to the input jacks. If you are switching ground, then you need to ensure that the jacks, etc. are insulated from the enclosure. Usually they have a limit stop which you can set to limit it to n inputs (and leave the remainder unused).
 
Feb 17, 2011 at 2:59 AM Post #5 of 27

tvattbjorn

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Hi Tech
I've used the elma 04-1434 as source selector in my b22. It seems to be exactly what you're looking for: three positions, 4 poles. It's available here:
 
http://www.schuro.de/elma-drehschalter-04.htm
 
Feb 19, 2011 at 3:12 PM Post #7 of 27

Pars

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It means that it is a make before break switch. Better for no pops between clicks, as it makes contact with the position you are going to before it breaks contact with the one you are leaving. It will briefly short the two; not sure if this has bad consequences or not, but they are often used, particularly in volume controls.
 
One of the switches that was recommended in the threads I linked to was the Electroswitch C4 series. Here is one on ebay:
http://cgi.ebay.com/ELECTROSWITCH-C4D0312NA-NSFP-C4D0312NA-/220677828480?pt=BI_Control_Systems_PLCs&hash=item33616c6f80
 
These are non-shorting. Here is the datasheet: http://www.electro-nc.com/rotaryus/c4.pdf
 
Feb 19, 2011 at 4:25 PM Post #8 of 27

technetium

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wow 179usd in shipping, hopes he offer a cheaper option :D
 
I think I will take that one, it seems to be pretty good quality and affordable :)
 
Feb 20, 2011 at 6:22 AM Post #10 of 27

technetium

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I have 2 channels which need to change at the same time, hence I need at least three 3 decks, and if I want more input options I need more poles, but as I have only 3 possible inputs, i need three input poles.
 
Feb 20, 2011 at 9:29 AM Post #11 of 27

tvattbjorn

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the 04-1434 has four center poles. Each center pole has 3 corresponding leads on the perimeter (12 in total) allowing you to switch between 3 sources (each source carrying left and right, plus 2 ground).
 
Feb 20, 2011 at 9:49 AM Post #12 of 27

technetium

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Okay, that config is new to me, most times there is one center pole per deck, however both grayhill and the electroswitch are significantly cheaper :wink:
 
Feb 22, 2011 at 3:56 PM Post #15 of 27

technetium

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Hmm it seems shipping from these suppliers in the US is very costly, so please remind me, why would this one not work:
 
http://cgi.ebay.co.uk/2pc-Rotary-Switch-2-Wafers-4-Poles-5-Positions-SRRN252-/140481727928?pt=LH_DefaultDomain_0&hash=item20b55d0db8
 
I has 4 poles hence I can even go balanced on it, and it has 5 positions.
 

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