Plug a Dreamcast with a SCART cable on a HD TV, why not ?

Posted by Molokh on 2017-04-13 .
Plug a Dreamcast with a SCART cable on a HD TV, why not ?
When talking about connecting a Dreamcast on HD TV, everyone will tell that the VGA adapter is the best solution. It definitely gives the best image, but it is certainly not the only mean for Europeans. Europe, unlike Japan and the United States, has had the chance to use SCART sockets (or SCART) as standard connections on televisions. SCART jacks are used to send an RGB signal that gives the best possible picture on CRTs. But what about HDTVs, and what does the Dreamcast displays when it's plugged directly the old way on our new TVs?
Some LCD screens offer RCA or even S-video jacks. I will break right away and tell you that the rendering of Dreamcast games with composite and S-video is really bad on those screens. The SCART standard is not a video standard but rather a connection standard. Its advantage is that it is very versatile. With its 21 pins it allows to transfer any type of signal invented until then and especially RGB signal. RGB is a signal that sends data from the three primary colors. A fourth signal is added: a composite signal, the exact same signal as on the RCA composite video jacks. The role of this composite signal is to serve as a joker for televisions that do not support RGB. In other cases, the composite signal is there only to transmit the Sync signal. This is the signal that allows the synchronization of the lines on the screen and which ensure the stability and the precision of the image.

The Dreamcast case

Here is the detail of a standard SCART Dreamcast cable:

On the diagram we see the Red, Green and Blue signals as well as the composite video signal which allows the Sync signal to be transmitted. For those who want to know more about the different types of Sync, I advise you to have a look a RetroRGB site which contains loads of information on RGB and its use with our old consoles.

After reading pages and pages on upscalers and RGB I had come to believe that the only solution to have a quality image with the Dreamcast is to go through VGA or an overpriced upscaler. But a practical test led me to realize that an RGB cable also gives very good results connected directly to an HDTV. Not as good as VGA but significantly better than RCA and S-Video.

If your television does not have a VGA connector but a RGB ready SCART connection then you still have a chance to have a quality image at lower cost. Caution however, there are scart sockets on LCD screens that are not RGB. Unfortunately I can not show you the actual screenshot of this solution. You can still have a look at some of my videos taken with a SCART / HDMI adapter:

What about the other consoles?

Among all the consoles I have tested on my TOSHIBA 32LV675D I got the best rendering with the Dreamcast, the Saturn and the Super Famicom. All three were connected with (official) RGB cables. On the other hand the PS2 and the Gamecube left a lot to be desired, which was unexpected as the Gamecube was plugged with the same cable as the Super Famicom ... For the PS2 my cable was of poor quality so I bought a SCART cable wired for sync-on-luma from RetrogamingCables. I chose Sync-on-Luminance because a lot of blog posts tell that they give the best result you can get with the PS2 without modification. And it is true. What an improvement ! For the PAL Gamecube I bought a RGB SCART cable with a SyncStripper built-in to get the best signal possible with a cable made specially for the console. The result is much better than with the Nintendo cable of my French Super Nintendo. It is important to have quality cables with good shielding to minimize interferences and have the clearest picture possible.

Of course these tips are only valid for Europe. The SCART standard was not popular in the United States where the best connectivity has long been the S-video and especially component video cables. Japan has a standard 21-pin plug standard, the JP21, which looks every bit like the SCART standard but the connections are totally different.

 Caution: Do not connect JP21 cables to SCART connections or you will damage your equipment!
The JP21 standard did not have the same popularity in Japan as the SCART in Europe. It was used primarily for some old computers and game consoles. It is rare to find televisions in Japan with this connection, D-Terminal being much more widespread.

As a conclusion

HD televisions are not originally made to display an analog RGB signal but rather digital signals, but in Europe, or at least in France, connecting a console with a SCART cable on a flat screen gives a result quite acceptable. You should try it at least once before investing in equipments more efficient, but also much more expensive.