Help me build a XLR switchbox?

stoutblock

"If it sounds good, it is good." Duke Ellington
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Hi guys, I've been looking for just the right XLR switchbox but have had no luck finding exactly what I want. I've decided I will probably need to build my own.

I need (4) stereo inputs and (1) stereo output. I want it all to be of the highest quality as to minimize any signal degradation.

This is what I have do far. The box footprint is to match my Decware RCA swithbox but the height shown is probably a minimum but would be OK to be a bit higher.

XLR switch box.jpg

I did find this article on a (1) input, (4) output switchbox.

http://www.diyaudioblog.com/2016/11/balanced-audio-switchbox-audiophile.html

And I would really like to know what exact Elma switch he used??? I think it is a type 04 but the website is over my head.

The biggest problem is I don't have a clue how to wire this up? I did find this two way switch schematic so I might be able to figure it out. I am mostly confused with how to exactly wire the switch lugs as compared to what this shows?

AB_Switch_Scheme.png

Also, any help on an exact box this size would be helpful?

Any of you out there more gifted than me want to help with the DIY project?
 
This is the Elma switch the guy used in the DIY link above. He never listed a code though?

Balanced XLR Switchbox Internal Elma crop.jpg
 
Dunno the exact model number of that, but I'd think the description/function would be something like; 4 position, 2 deck, 2 poles per deck.

The 4 position part gets you the four input selections.

The 2 decks would be to use one deck for left channel and one deck for right channel.

Then, the 2 poles per deck would be for the (+) and (-) signal wires.
 
Dunno the exact model number of that, but I'd think the description/function would be something like; 4 position, 2 deck, 2 poles per deck.

The 4 position part gets you the four input selections.

The 2 decks would be to use one deck for left channel and one deck for right channel.

Then, the 2 poles per deck would be for the (+) and (-) signal wires.

The terms they use on their website; Wafers, Poles, Positions and shorting or non-shorting. Also 15 deg or 30 deg that I assume is angles between positions?
 
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Wafers = decks.

Yeah, I believe the degrees would be rotation between positions.

Shorting is essentially make before break, non-shorting is break before make. I'd think non-shorting would be the pick.
 
Wafers = decks.

Yeah, I believe the degrees would be rotation between positions.

Shorting is essentially make before break, non-shorting is break before make. I'd think non-shorting would be the pick.

So the DIY link above recommended "make before break" for his switcher?

How many poles?
 
Sure, I understand the conventions. Just not why you'd want shorting...although a bit more reading elsewhere suggests shorting is commonly used for audio input switching.
 
So assuming XLR3 standard. Pin 1 = common ground, Pin 2 = positive, Pin 3 = negative.

I assume the common ground (Pin 1) does not need to be switched?

I use one wafer (deck) with two poles for each channel. One pole for positive and one pole for negative.

I think I am getting it!

Now short vs non-short?
 
Sure, I understand the conventions. Just not why you'd want shorting...although a bit more reading elsewhere suggests shorting is commonly used for audio input switching.

Yes, I am reading the same, that shorting is the preferred audio source selection? Would not both sources be on for a short period? Maybe this avoids popping noise during switch?

I also looked at some other XLR switch boxes and they say specifically "break before make" ?

http://www.fullcompass.com/prod/049...MIuuWUh5C81gIVh4l-Ch1W7AguEAQYAyABEgKscfD_BwE
 
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I looked at Goldpoint's website and they use a four pole single wafer for their XLR switchbox. I guess that will also work to put both channels on one wafer?

I really get mixed input on shorting vs non-shorting? Their seems to be different opinions out there???
 
I looked at Goldpoint's website and they use a four pole single wafer for their XLR switchbox. I guess that will also work to put both channels on one wafer?

I really get mixed input on shorting vs non-shorting? Their seems to be different opinions out there???

Yeah, if you had a single deck, 4 position, 4 pole switch that would accomplish the same. Or, a 4 deck, 4 position, single pole. There are a number of ways it can be accomplished. Dunno if one is any better than the other. I'd think the single deck would be pretty crowded.

Not sure what more to say on the shorting vs. non.
 
Well I chatted with one AK'r who made a switchbox with non-shorting and had no problem or noise during switching. That's good enough for me plus it makes sense.

I was thinking of using Goldpoint but they don't state on their website if their switches are shorting or non-shorting?
 
I was able to chat with a tech at Goldpoint and he confirmed that non-shorting is the right decision. I ended up ordering one of their selector switches instead of the Elma. It seems to be a fine product and priced accordingly...

I ordered all the parts last night.

- Goldpoint 2P-4T-2D switch
- Eightwood ZBX104 aluminum case (A little smaller than I was looking for).
- (8) Neutrik female XLR connectors
- (2) Neurtik male XLR connectors
- (20') of Neotech solid UPOCC 22 AWG teflon shielded wire
- 15/16" Greenlee hole punch
- Silver solder

I'm not sure what I will use for a knob yet.

A little more expensive than I was originally thinking but it will be great to not have to switch XLR cables depending on the source I am listening to :)
 
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If you like them, a chickenhead makes a good choice for this duty.

Then again, for myself, I got an AudioNote matte silver 1" knob. Very understated. Against a black project box, it looks good on the shelf.
 
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