Whats with the SNES hum over RGB/Scart cable?

Over a few years I have owned a number of different SNES consoles (Japanese or PAL) and using a variety of TVs and different RGB/Scart cables I can confirm that I always got an annoying hum in the background which increases on how bright the picture is.

Now I just got myself a very nice SNES, PAL model as well as an RGB/Scart cable from consolgoods,co.uk, and guess what? HUMMMMMMM. I contacted the seller and he confirmed that this is pretty much 'normal'.

Any idea how to fix this, or at least, if I buy an official SNES RGB/Scart the hum will go away?

:mad-new:

 

The hum is usually caused by cross-talk from the video signals interfering with the audio. You could try modifying the cable and run the audio separately (down another cable), or even try attaching some of those snap-on Ferrite cores to each ends of the cable.
Not sure how well the latter will work, but you often see them attached to official SCART cables (IIRC).

 

It is normal, but certain cables are worse than others. It helps a lot if the signals are properly shielded. APE made me a cable from pieces of a SCART cable and a CAT5 cable for the wiring. It drastically reduced the humming sound (it's still present, but not nearly as bad as it was before), and even the picture looks slightly sharper.

 

I'd imagine a high pass filter would help but would add to the complexity. Finding replacement cable that has each of the wires individually shielded would be a big help and probably cost a pretty penny.

 

Official cables aren't a common sight. As I understand Nintendo released only French (Scart for PAL SNES) and Japanese (JPN RGB for NTSC SNES) versions. Or two out of four possible wiring types in other words.

 

Thanks for the info. I have now bought an official RGB Scart cable from Ebay.fr - hope it turns out better!

Btw, does the Megadrive(2?) suffer from the same problem?

 

I don't recall if the Genesis 2 had a buzzing problem, but I don't think it does. However, you're better off going with a Model 1: way better RGB video quality, and better audio. The NTSC model, anyway.

 

Well I guess at the risk of vertical bars. There's quite a huge topic about that here.

 

Well I already have a brand new PAL Asian MD2 on the way.

 

Why get PAL? I thought you wanted to play US games.

 

Well... PAL MD2 + 60hz mod + Everdrive MD. I got the MD2 because it was brand new.

 

Small update.... I just got the official RGB/Scart for the PAL SNES (Ebay.fr). It is FANTASTIC. Absolutely no humming at all and awesome picture. I will never buy a non official scart cable of anything again (if possible).

 

Man, is that the solution? I'm having this same problem too, I'd always assumed there was a noise issue with my setup. It's really annoying, since the picture is perfect, and only seems to really appear when I plug the console into my AV receiver. I don't think it's cross-talk, since my PAL SNES cable has a seperate audio cable and still has the buzzing. Would replacing the wiring solve the issue? Or should I buy an official cable? I've got a 3rd party Sega Saturn SCART cable coming, and I notice the wire is much thicker than the others I have. If this one works fine, I can assume that replacing the wiring on the other cables with something thicker and better shielded would fix them as well

 

Well for me, getting an official RGB cable worked. I am sure they are way better made than the usual crap.

 

Do you guys know if SNES SCART cables have the same number of wires as a normal SCART to SCART cable? I was thinking I'd just buy a well-shielded SCART cable, chop one of the ends off and solder the plug from the original cable in, but that might become complicated if the original cables doesn't have the same number of wires

 

A SNES SCART will only carry the necessary outputs and ground wires. With a normal SCART to SCART cable, there is double the amount of cables as it's designed to carry both input and output.

I guess one of the problems with these SNES SCART cables (and other SCART cables in general) is that they don't have internal shielding on the video and RGB lines, despite the fact that there is provision for (separate) ground points. No wonder there is interference on the audio!

Take a look at the SCART pinout diagram for more info. Note where it says on the pinout regarding Pin 21:

"This pin is part of the shell/surround of the male connector. It is often connected to the overall screen in a cheap cable. In equipment, Pin 21 should be connected separately to the chassis, but often it is merely connected to all the other ground pins".

 

Well, I've acquired an official Nintendo SNES RGB SCART cable, aaaaaaand... There's no improvement, despite the thicker cable and better build! I'm starting to think it's the console, not the cable, since the Saturn and Nintendo 64 don't have this issue. At the same time, I don't have the noise issue when I use the official composite cable, so I have no idea.

 

I got an official cable and theres definite improvement for me over the 3rd party ones. (but I had issues with the N64 too with the same 3rd party cables)

 

I had issues with picture noise with a 3rd party N64 S-video cable, which was resolved by replacing the wiring with a better shielded one. But in the case of the SNES, even replacing the entire cable hasn't made any difference. I have no idea what to make of this.

 

Here's sonic running on the mega everdrive, on a 32x with scart cable via an RGB to component converter.

Ghosting and bzzz






Is there a way to fix it without destroying the cable and working only on the scart end of the cable?