AV Reciever Comp. Video Inputs: why active electronics?

Discussion in 'AV Receivers' started by StevePrince, Mar 29, 2004.

  1. StevePrince

    StevePrince Auditioning

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    Video Techies:

    On AV receivers, why is there a bandwidth associated with switching the (typical) two component video inputs? It would seem there are active electronics associatied with switching between the two inputs. Why not just passively switch between the two?

    As a follow up, why is there a quantum leap in price to go from 2 component video inputs to 3 or more? Is there a fundemental reason why most AV receivers only have 2 component video inputs?
     
  2. LanceJ

    LanceJ Producer

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    This is just an educated guess but since the switching in most receivers is done using solid-state electronics, that signal has to pass through them (some form of SCR? triac? not sure). And it looks like certain components can't handle frequencies above a certain point. And these components may be rather pricey since they have to handle such extreme frequencies.

    Passive switching: they could use mechanical relays or something similar but these would definitely be pricey: they require their own set of electronics to activate the relay's magnetic coil; and the switching contacts themselves would have to be of high quality to handle those high frequencies. And, they make noise & to some people that equates to "cheap" (though personally I like to hear my own receiver make its various clicking and metallic tapping noises when I select various functions--they make it feel like something important is happening in there [​IMG] ).

    And the amount of component inputs is all part of controlling pricing for a certain category & also partly marketing. Right now I only use one dvd player but at the most I would use two, but only one would use the TV's component input. And I don't have Tivo, digital or HD cable either so that's out of the picture (haha). Don't play video games so that's out too. So as Seven-Of-Nine would say, component switching for me is irrelevant. [​IMG] [​IMG]

    But obviously there are people who do need more component inputs but I'll bet the manufacturers figure they will just use the TV's extra inputs. Also (more guessing here) since S-video is so close in quality to component quality, they might think except for one of the user's dvd players and HD cable box >>> a total of 2 inputs, all other video signal sources will be of lesser quality & the user can just use the S-video or composite inputs for those.

    LJ
     
  3. BrianWoerndle

    BrianWoerndle Supporting Actor

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    Some receivers do use relays to switch component inputs. My Denon 3803 uses relays and is rated up to 100mhz bandwidth.
     
  4. Bob McElfresh

    Bob McElfresh Producer

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    Looked at the back of a modern reciever lately? It's getting kind of crowded. Extra connectors cost money because of this.

    This thread on Inexpensive HD Video Switching talks about several external video switch box's that cost a lot less than a new receiver, and tend to give you 4 inputs.
     

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