Good place to get shielded RGB cables now?

The place for all discussion on gaming hardware
User avatar
bobrocks95
Posts: 3462
Joined: Mon Apr 30, 2012 2:27 am
Location: Kentucky

Re: Good place to get shielded RGB cables now?

Post by bobrocks95 »

evil_ash_xero wrote:Interesting. Can their SNES cables actually get rid of that interference? I get that, even with the official cables. I still get interference (not very noticeable now) on the SNES Mini (RGB modded).
I wonder if that would fix that? That's like the worst offender, when it comes to interference.
What kind of interference?
PS1 Disc-Based Game ID BIOS patch for MemCard Pro and SD2PSX automatic VMC switching.
User avatar
Lawfer
Posts: 2283
Joined: Fri Dec 01, 2006 3:30 am

Re: Good place to get shielded RGB cables now?

Post by Lawfer »

maxtherabbit wrote:thicc cables are the best
Indeed, this is very important for three reasons:

1. AWG (smaller the thicker, means more copper/silver)
2. Shielding
3. Real proper 75 Ohm
User avatar
evil_ash_xero
Posts: 6181
Joined: Thu Jul 12, 2007 6:33 am
Location: Where the fish lives

Re: Good place to get shielded RGB cables now?

Post by evil_ash_xero »

bobrocks95 wrote:
evil_ash_xero wrote:Interesting. Can their SNES cables actually get rid of that interference? I get that, even with the official cables. I still get interference (not very noticeable now) on the SNES Mini (RGB modded).
I wonder if that would fix that? That's like the worst offender, when it comes to interference.
What kind of interference?
The SNES and SNES mini have horrible interference, unless you use official cables, or really well shielded cables.

Buzzing, rolling waves on your screen...the whole shebang. In my experience, the mini is actually worse than the first one.
User avatar
Gara
Posts: 317
Joined: Sat Jan 13, 2018 12:33 pm
Location: Northern California

Re: Good place to get shielded RGB cables now?

Post by Gara »

evil_ash_xero wrote:
bobrocks95 wrote:
evil_ash_xero wrote:Interesting. Can their SNES cables actually get rid of that interference? I get that, even with the official cables. I still get interference (not very noticeable now) on the SNES Mini (RGB modded).
I wonder if that would fix that? That's like the worst offender, when it comes to interference.
What kind of interference?
The SNES and SNES mini have horrible interference, unless you use official cables, or really well shielded cables.

Buzzing, rolling waves on your screen...the whole shebang. In my experience, the mini is actually worse than the first one.
My Snes Mini doesn't have any of those problems. I'm using a Retro Access cable but the system was also heavily modded. Voultars RGB board, c11 replaced. new voltage regulator, recapped power supply, and a digital audio mod.
thebigcheese
Posts: 707
Joined: Sun Aug 21, 2016 5:18 pm

Re: Good place to get shielded RGB cables now?

Post by thebigcheese »

I also have never had any of those problems with either an unmodded fat SNES or my mini with Voultar's board in it. Heck I'm not even using the nice Retro Access cable, I'm just using the cheap cable they don't even sell anymore. My NES had audio buzz until I upgraded, but I've otherwise had very good results with Nintendo systems.
SamIAm
Posts: 475
Joined: Thu Mar 03, 2005 1:09 am

Re: Good place to get shielded RGB cables now?

Post by SamIAm »

I am in the middle of an adventure in making my own cables for an Extron Crosspoint connecting twelve consoles and six monitors, and I've done some research relevant to this thread.

My brilliant idea was to get a 50m VGA cable on clearance, cut it up into 20 lengths of 2.5 meters each, and cannibalize my crappy old 3rd party SCART cables for console connectors. Components like resistors, capacitors, and sync strippers will be contained in small breakout-boxes, and BNC connectors will be provided cheaply by these. I'll take pictures when everything is done.

The cable has proper 75-ohm coax lines for the RGB signals, which is nice, but it's perhaps not as relevant for 240p gamers as that Retro Access article makes it seem. Any individually shielded wires would likely do the job just as well.

The argument in favor of 75-ohm coax is that it prevents signal reflections. This image illustrates how reflections happen when a wave changes the medium it's travelling through. For video transmissions, this occurs whether you change the type of cable halfway through the line or simply use the wrong type of cable altogether.

Yet this phenomenon in general only occurs when the length of the mismatched medium exceeds 1/4 of the signal's wavelength.

Most 320x240p systems have dot-clocks around 7MHz. 512-pixel-wide modes are usually around 10MHz, and the Saturn's 702-pixel-wide resolution uses a 14.2MHz dot-clock, just FYI. At the speed of light in a vacuum, a 7MHz signal has a wavelength of about 42.3 meters. One quarter of that is about 10.5 meters, and a general guideline is to halve that value again since electrical signals don't actually travel at light speed.

Therefore, as long as you're only playing low-res games, the phenomenon of reflection because of impedance mismatching shouldn't happen at all until the length of your mismatched cable exceeds five meters. Furthermore, the amount of reflecting starts small and grows incrementally as your cable gets longer, and it might not actually become visible until the cable is longer than anyone would ever use in a typical game-room setup.

There is a caveat, however: fast rises and falls in a signal (imagine a black pixel followed by a white pixel, and vice-versa) happen at an effectively much higher frequency than the overall clock. I've read that people dealing with the transmission of digital signals assume they're 20x faster. For a 7MHz dot-clock system, that would mean you would see reflecting after a mere 26cm of mismatched cable. However, I'm skeptical that such reflections would actually be perceptible, especially in CRTs displaying analog 240p natively. A setup involving digital conversion, I suppose, could be a different story.

Tl;dr - If you're only running a couple meters of cable and if you're only running low-res systems, the difference between proper 75-ohm coax and any other random shielded cable is likely negligible.
User avatar
ApolloBoy
Posts: 938
Joined: Sat Jan 28, 2012 7:17 pm
Location: San Jose, CA

Re: Good place to get shielded RGB cables now?

Post by ApolloBoy »

evil_ash_xero wrote:
bobrocks95 wrote:
evil_ash_xero wrote:Interesting. Can their SNES cables actually get rid of that interference? I get that, even with the official cables. I still get interference (not very noticeable now) on the SNES Mini (RGB modded).
I wonder if that would fix that? That's like the worst offender, when it comes to interference.
What kind of interference?
The SNES and SNES mini have horrible interference, unless you use official cables, or really well shielded cables.

Buzzing, rolling waves on your screen...the whole shebang. In my experience, the mini is actually worse than the first one.
Neither my SNES mini or Super Fami do that. Are you sure you aren't using a cheapo PSU?
Post Reply