Good source switcher

I'm in need to switch video and audio. I know they make manual switchers to do this, but I would like to make my own. I need to switch audio from multi-sources go into my amp, and video from multi sources switched to a output connector. I was thinking of using relays, but dont they have bad noise issues and just dont work well with audio/video? How can I switch reliably (with little to no switching POP) and mantain good quality?
I'm not clear as to what noise issues you mean regarding relays. If you mean the mechanical click as the relay engages or disengages, then yes they make noise. This is easy enough to damp, however. If you're getting a pop through your system when you change inputs, don't blame the relay...there's DC offset at one or more of your inputs. Track down the source of the DC and you'll be able to cure the problem. If nothing else, you can use a capacitor to couple the offending unit to the switching unit. Keep in mind that it will pop regardless of whether you use a relay or any other kind of switch--the DC will still be there.
I don't do much in the way of video, so I'm not in a position to say if there are any special requirements involved. In general, since you're working with high frequencies, I'd suggest good shielding and ground practices.



Disabled Account
2006-01-18 8:08 pm
Video is very high frequency. You should probably use relays with controlled impedance, or the far, far easier option of logic. You can buy say an HDMI switcher for something like $40 or even less. I've taken one apart and it had ICs you can probably find on Digikey or the like (I've since returned it so I don't remember the part number).