8 channel switch box

alex! · 2nd December 2009

Greetings slutz,

I had built a little switch box to toggle between inputs from 2 locations and thought I'd share my work with you folks. It hasn't yet passed the real world test but I got the pinouts right and no shorting on the first go with the continuity test. It works both ways so for the needs of where it will be installed the I'll probably need to change the sex of the dsubs. The switches are hermetically sealed triple pole double throw, I'm hoping they won't introduce any audible distortion. It's my first time I build a custom box like this and found the hardest part was being precise on the metal work, the dsub chassis aren't as straight as I would have liked them to be.

DannyL · 3rd December 2009

Your project looks fairly neat and tidy.

Have a look at Greenlee for making holes in things:

Greenlee Products - Greenlee A Textron Company

I often cover a surface with masking tape, then pencil in my holes and so forth, using basic drafting tools. The Greenlee punches are fairly foolproof and cut really nice holes.

I would be concerned about the possibility of loud pops when switching from one source to the other. With microphones this would almost be a certainty.

Let us know how it works.

Danny

alex! · 3rd December 2009

A dsub punch would be very nice to have indeed! However, I wouldn't use it all that much and that's why I never bought one.

There are definitely pops when switching, I made a mockup and tested it before I went out and bought all the parts and really got to work on it. Would there have been a way to avoid this and can switching with phantom power on cause some damage?

DannyL · 5th December 2009

You can cause damage by switching phantom power: older capsules that are more fragile may not react well to a sudden excursion as power is applied instantaneously. If there is a slight time difference between pin 2 nd 3 connecting you will damage ribbon mics. You probably will not do much, if any damage to your console. It is generally best to connect a mic, and then power up the 48v.

You could use transformers and just switch the primaries, with the secondaries hard wired to the outputs. You would require external phantom for each source at the switch or local phantom at the mics. You could buy a 48v supply and wire it to all the inputs of your box (using switches), before the transformers......

This solution would certainly be more expensive.

Go to: All About Circuits Forum and have a look around for some solutions

Danny

2nd December 2009	#1
alex! Gear Head Joined: Aug 2008 Posts: 71 Thread Starter	8 channel switch box Greetings slutz, I had built a little switch box to toggle between inputs from 2 locations and thought I'd share my work with you folks. It hasn't yet passed the real world test but I got the pinouts right and no shorting on the first go with the continuity test. It works both ways so for the needs of where it will be installed the I'll probably need to change the sex of the dsubs. The switches are hermetically sealed triple pole double throw, I'm hoping they won't introduce any audible distortion. It's my first time I build a custom box like this and found the hardest part was being precise on the metal work, the dsub chassis aren't as straight as I would have liked them to be. Attached Thumbnails

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3rd December 2009	#2
DannyL Gear maniac Joined: Aug 2009 Location: Sao Paulo Posts: 283	Your project looks fairly neat and tidy. Have a look at Greenlee for making holes in things: Greenlee Products - Greenlee A Textron Company I often cover a surface with masking tape, then pencil in my holes and so forth, using basic drafting tools. The Greenlee punches are fairly foolproof and cut really nice holes. I would be concerned about the possibility of loud pops when switching from one source to the other. With microphones this would almost be a certainty. Let us know how it works. Danny

5th December 2009	#4
DannyL Gear maniac Joined: Aug 2009 Location: Sao Paulo Posts: 283	You can cause damage by switching phantom power: older capsules that are more fragile may not react well to a sudden excursion as power is applied instantaneously. If there is a slight time difference between pin 2 nd 3 connecting you will damage ribbon mics. You probably will not do much, if any damage to your console. It is generally best to connect a mic, and then power up the 48v. You could use transformers and just switch the primaries, with the secondaries hard wired to the outputs. You would require external phantom for each source at the switch or local phantom at the mics. You could buy a 48v supply and wire it to all the inputs of your box (using switches), before the transformers...... This solution would certainly be more expensive. Go to: All About Circuits Forum and have a look around for some solutions Danny