SCART RGB DA

"Dave Plowman (News)" wrote in message ...
In article ,
Graham. wrote:
Pro monitors often have automatic termination, so daisy chaining them
on composite works just fine as all but the last one simply bridges
the line.

Never seen that and I can't see how the last monitor "knows" it is at
the end of the line without some sophisticated "time domain" probing.
Seen plenty with slide switches to select bridge or term of course.

Been around for 10 years or more. Could be the last one 'knows' because it
has only one video cable plugged in? (But my guess is it's more
sophisticated than that.)

I've snipped the 75R terminator on many a domestic TV in my time
and relied on a terminator on the unused port of the T piece at the end.

Domestic TVs with BNCs?

I think I remember one or two in the 80s. The ones I was referring to didn't,
They had a SCART socket, and we plugged in a plug with short leads with a BNC in-line
female for composite and a 6 pin domino DIN female for RGB


--
Graham.

%Profound_observation%

On 14/09/2010 10:42, Dave Plowman (News) wrote:
In ,
wrote:
Why are SCART DAs - to allow say two TVs to be driven off the one DVD
player or whatever (in RGB) so expensive? VGA DAs are very much
cheaper. Is it just supply and demand?

They are probably little more than three emitter followers.

Interesting - what would be a suitable transistor? I'm more an audio sort
of person. ;-)


Use anything you've got to hand. Don't forget that transistors mainly
used for audio will still work at far higher frequencies than you are
interested in.

It's a long time since germanium transistor days when special RF types
were needed to work on medium wave ...!

--

Terry

In article ,
Terry Casey wrote:
On 14/09/2010 10:42, Dave Plowman (News) wrote:
In ,
wrote:
Why are SCART DAs - to allow say two TVs to be driven off the one DVD
player or whatever (in RGB) so expensive? VGA DAs are very much
cheaper. Is it just supply and demand?

They are probably little more than three emitter followers.

Interesting - what would be a suitable transistor? I'm more an audio sort
of person. ;-)


Use anything you've got to hand. Don't forget that transistors mainly
used for audio will still work at far higher frequencies than you are
interested in.

It's a long time since germanium transistor days when special RF types
were needed to work on medium wave ...!

I can remember in the late 60s, a design engineer moaning that even power
transistors worked up to video frequencies. It made designing power
supplies so much more compicated.

--
From KT24

Using a RISC OS computer running v5.16

"Terry Casey" wrote in message
...
On 14/09/2010 10:42, Dave Plowman (News) wrote:
In ,
wrote:
Why are SCART DAs - to allow say two TVs to be driven off the one DVD
player or whatever (in RGB) so expensive? VGA DAs are very much
cheaper. Is it just supply and demand?

They are probably little more than three emitter followers.

Interesting - what would be a suitable transistor? I'm more an audio sort
of person. ;-)


Use anything you've got to hand. Don't forget that transistors mainly used
for audio will still work at far higher frequencies than you are
interested in.

It's a long time since germanium transistor days when special RF types
were needed to work on medium wave ...!

It was White Spot for RF if you couldn't afford OC44s.

Red (or blue) Spot for audio.

Green Spot for audio output.

--
Max Demian

wrote:
Why are SCART DAs - to allow say two TVs to be driven off the one DVD
player or whatever (in RGB) so expensive? VGA DAs are very much
cheaper. Is it just supply and demand?

They are probably little more than three emitter followers.

Interesting - what would be a suitable transistor? I'm more an audio sort
of person. ;-)


Use anything you've got to hand. Don't forget that transistors mainly used for audio will still work at far higher frequencies
than you are interested in.

It's a long time since germanium transistor days when special RF types were needed to work on medium wave ...!

It was White Spot for RF if you couldn't afford OC44s.

Red (or blue) Spot for audio.

Green Spot for audio output.
And scrape the black paint off an OC71 to make an OCP71. Until Mullard got wise to it.

--
Graham.

%Profound_observation%

In article ,
Terry Casey wrote:
On 14/09/2010 10:42, Dave Plowman (News) wrote:
In ,
wrote:
Why are SCART DAs - to allow say two TVs to be driven off the one DVD
player or whatever (in RGB) so expensive? VGA DAs are very much
cheaper. Is it just supply and demand?

They are probably little more than three emitter followers.

Interesting - what would be a suitable transistor? I'm more an audio
sort of person. ;-)


Use anything you've got to hand. Don't forget that transistors mainly
used for audio will still work at far higher frequencies than you are
interested in.

I might well have a play, then. Now the nights are drawing in.

--
*Very funny Scotty, now beam down my clothes.

Dave Plowman London SW
To e-mail, change noise into sound.

On 17/09/2010 10:48, Dave Plowman (News) wrote:


Use anything you've got to hand. Don't forget that transistors mainly
used for audio will still work at far higher frequencies than you are
interested in.

I might well have a play, then. Now the nights are drawing in.


http://www.epanorama.net/documents/video/videoamp.html

Lots of chips around to do the same thing. Less legs to solder.

--
Adrian C