Building an A/V Selector

[Electric Rain]

Hi, I'm in need of an A/V (Stereo Audio) selector with at least 6 outputs. I'd like about 10, but I only need 6. They're too expensive to buy and there are certain things I'd like to customize about it too. So therefore I want to build it myself. But I don't think I can just use a switch for this. I'm pretty sure I need SOME kind of circuitry unless I want a HORRIBLE quality. So can anyone give me the schematics for one of these? Thanks.

Rain

 

[crust]

At diyaudio.com there were several people who built a preamplifier. If you just skip the tone, volume, etc ... it is identical to what you want. I think they even had a remote control and so on. IIRC, it used mechanical relays to switch between inputs to minimize the path impedance.

 

[Electric Rain]

Thanks, but, what about the video? The video was my main problem. If I'm correct, audio doesn't need as good of a connection as video does to assure good quality. So what do you think I should do about that? :? Again, thanks for the audio solution. :wink:

 

[Nigel Goodwin]

Thanks, but, what about the video? The video was my main problem. If I'm correct, audio doesn't need as good of a connection as video does to assure good quality. So what do you think I should do about that? :? Again, thanks for the audio solution. :wink:

You could use relays to switch the video as well, but for both you could use CMOS switches, there are various ones designed specifically for switching video signals, but mostly only two way

The video ones usually have an internal amplifier, to compensate for the 75 ohm output resistor you use.

 

[Electric Rain]

I can use relays for the video too? Cool! I have three questions though,
1. Will the quality be reduced at all?
2. What kind of relay should I use? Contact Rating? Coil Resistance? What's best?
3. Can all of the grounds be tied together? Or should the relays have two poles for the ground and the signal?

Thanks a lot Nigel,


Rain

 

[Nigel Goodwin]

I can use relays for the video too? Cool! I have three questions though,
1. Will the quality be reduced at all?

Not so you would notice, or probably not so you could measrure either!.

2. What kind of relay should I use? Contact Rating? Coil Resistance? What's best?

The current requirements for the contacts are very low, anything would do, sealed ones would probably be best - pick the coils for the voltage you intend to use.

3. Can all of the grounds be tied together? Or should the relays have two poles for the ground and the signal?

Just switch the signal, you can simply join all the grounds together.

 

[Electric Rain]

Hey! Thanks a lot Nigel! That answers all of my question very well! I should have no problem building it now. It's so simple... so it makes me wonder, how do they get off selling them so expensive in the stores? Well, I guess they're not THAT much, but still...

Well anyway, thanks again Nigel.

Rain