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Passive source selector - rotary switch

post #1 of 27
2/16/11 at 8:48am
Thread Starter 

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 :)

 

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post #2 of 27
2/16/11 at 10:18am

You'll need more than 2 decks to switch the ground(s). Take a look at this thread, including links within it:

http://www.head-fi.org/forum/thread/424267/recommendations-for-an-input-selector-switch

 

Also, a google search on

source selector switch site:head-fi.org

might show something as well.

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post #3 of 27
2/16/11 at 11:32am
Thread Starter 

Well I have read that, and it does not make much sense to me, how many decks do I need and how to wire it up?

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post #4 of 27
2/16/11 at 1:56pm

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).

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post #5 of 27
2/16/11 at 11:59pm

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

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post #6 of 27
2/19/11 at 8:57am
Thread Starter 

Hi Tvætbjørn :)

 

That elma, does only have two decks right? I need atleast 3 deck I believe.

 

This Grayhill:

http://cgi.ebay.com/Grayhill-Rotary-switch-08-3-Decks-4-pole-Shorting-/140503449357?pt=LH_DefaultDomain_0&hash=item20b6a87f0d#ht_500wt_1156

 

will this work, what does it mean that it is shorting?

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post #7 of 27
2/19/11 at 12:12pm

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

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post #8 of 27
2/19/11 at 1:25pm
Thread Starter 

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 :)

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post #9 of 27
2/20/11 at 2:51am

Sorry, I may be a little slow. The 04-1434 is just one deck, but it still switches 4 poles (so you can even have separated grounds), so why do you need more decks?

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post #10 of 27
2/20/11 at 3:22am
Thread Starter 

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.

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post #11 of 27
2/20/11 at 6:29am

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).

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post #12 of 27
2/20/11 at 6:49am
Thread Starter 

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 ;)

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post #13 of 27
2/20/11 at 7:54am

quite right, I didn't see their prices, just that shipping rate of 179 which admittedly is a little steep :-s

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post #14 of 27
2/20/11 at 8:55am
Thread Starter 

I hope they have a cheaper option :D

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post #15 of 27
2/22/11 at 12:56pm
Thread Starter 

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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