I am considering making a switch box for 2 or 3 digital line sources with a line out to a DAC. I am thinking in terms of coaxial wires. I assume a regular rotary switch will do but i am unclear about handling the earth connection. Do I switch eart as well as line or do I connect to common earth in the box?
I would be very grateful for any advice.
P
I would be very grateful for any advice.
P
I would not switch earth. Build it as though it was for RF - it is! Short connections, low inductance. If possible, measure its effect on impedance at high HF or low VHF. A local radio amateur might have an antenna analyser you can use.
Hej, Åke, thanks for the hint !
I will look into this. I see there are some items there that might suit my needs, such as this: 3 WAY PHONO RCA STEREO AUDIO INPUT SELECTOR SWITCH | eBay
My digital sources already have volume control. For digital signal I would only need one channel.
I will look into this. I see there are some items there that might suit my needs, such as this: 3 WAY PHONO RCA STEREO AUDIO INPUT SELECTOR SWITCH | eBay
My digital sources already have volume control. For digital signal I would only need one channel.
Analogue selector boxes might not work too well. Depends how they are constructed. You need to maintain some rough approximation to 75 ohm impedance through the box.
Thank you Frank!
I will look into this. Perhaps one of these would do?:
Switch Boxes - Networking components for OEMs and Systems Integrators in Pittsburgh, PA
I will look into this. Perhaps one of these would do?:
Switch Boxes - Networking components for OEMs and Systems Integrators in Pittsburgh, PA
The BNC ones are almost what you need, except that they will be 50 ohm instead of 75. They might be good enough if all connections are short.
10base-T networking is (was) classic 50R terminated BNC / coax, but I have never seen this switched as in a "1 of n" selector! Besides, that is VERY dead technology!
Video switches, however, can use coax center-wire switches - reeds are good and make keeping the 75R impedance within bounds very easy.
Video switches, however, can use coax center-wire switches - reeds are good and make keeping the 75R impedance within bounds very easy.
Thank you. I know very little electronics as this question may or may not confirm: Does a 25 ohm resistor fitted in series make any sense?
it looks like tv connectors to me....
on the other hand it looks like the BNC is 75 ohm as pr. here:
4 In 1 Out Composite Video Switcher
on the other hand it looks like the BNC is 75 ohm as pr. here:
4 In 1 Out Composite Video Switcher
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