Misc. questions on RGB console cables

[Milsancho]

Hello,

I hope you don’t mind me asking these in one thread, despite not being too related each other:

I have some of these NTSC-J Saturn C-sync cables from a couple of years ago: https://videogameperfection.com/2015/03/27/thefoo-saturn-review/

But then I realize that RGC’s similar cables has this in the specs page: “CSYNC output correctly attenuated for 75Ω operation (NTSC CSYNC MODEL).”

https://www.retrogamingcables.co.uk/packapunch-range/SEGA-SATURN-RGB-SCART-PACKAPUNCH-PRO-CABLE

Should I’d be worried about mine not being like this? I use them directly on PAL TV sets.

I’ve also noticed there are Packapunch luma-sync PS cables now for purchase, what’s your opinion when comparing them with the regular RGB cables?:

https://www.retrogamingcables.co.uk/packapunch-range/SONY-PLAYSTATION-PACKAPUNCH-RGB-SCART-CABLE-PRO

https://www.retrogamingcables.co.uk/sony-playstation-1-2-ps1-ps2-rgb-scart-cable-lead

The Packapunch cable can be either, with capacitors (PS1) or without (PS2). For the regular cables, they state:

“It also benefits from internal capacitors connected in series with each RGB video line to remove any direct current (DC) signals, which may impede the true alternating current signal used in signal transmissions.”

Though it seems both versions work on both consoles, why is it that for the PS2 this is not needed and how exactly does this affect performance? I’d like to know what’s the better option for both consoles, in other words.

Thanks!

[BuckoA51]

Should I’d be worried about mine not being like this? I use them directly on PAL TV sets.

Probably, I am not 100% sure on the Saturn’s output but if it’s not properly attenuated for 75 ohm then it’s outputting TTL spec signal and this is outside of spec. It MIGHT cause wear and tear to your TV.

For the PlayStation, the PS1 cable is recommended for the PS1 and the PS2 cable is recommended for the PS2 🙂 Seriously though I’m not certain why there’s this minor difference. I’d always go for luma sync as I’ve had dot-crawl issues on all my composite video for sync PS1 cables.

As for the Pack a Punch, I’m going to take a look at some if he ever gets them back in stock.

[Milsancho]

Yeah; I want to try sync-on-luma on Playstations… I’d like to buy C-sync cables actually since you never know where will they be plugged in the future, but as I don’t know if the sync stripper is placed at the SCART plug (which would be quite pointless in regards to signal quality), I think luma-sync is a safer bet…

For the PlayStation, the PS1 cable is recommended for the PS1 and the PS2 cable is recommended for the PS2

Well, I meant to say if you had to choose one cable for both systems, which one sounds like the better option.

Probably, I am not 100% sure on the Saturn’s output but if it’s not properly attenuated for 75 ohm then it’s outputting TTL spec signal and this is outside of spec. It MIGHT cause wear and tear to your TV.

So it’s possible that Sega assumed that the customer would always use a cable with these attenuation properties!? Where could I learn a bit about this 75 Ohm/TTL signal thing and the possible effects of the latter on TV sets, please? It’s totally new to me.

And maybe you’re allowed to share The Foo’s e-mail (non-Ebay) address so that I can ask him directly about his cables?

[BuckoA51]

Yeah; I want to try sync-on-luma on Playstations… I’d like to buy C-sync cables actually since you never know where will they be plugged in the future, but as I don’t know if the sync stripper is placed at the SCART plug (which would be quite pointless in regards to signal quality), I think luma-sync is a safer bet…

PlayStation’s do not output clean composite sync so any clean sync PS cable you buy will be using a sync stripper.

So it’s possible that Sega assumed that the customer would always use a cable with these attenuation properties!?

Much more likely they assumed everyone would simply use composite video for sync, save for a few folks hooking up arcade monitors perhaps.

And maybe you’re allowed to share The Foo’s e-mail (non-Ebay) address so that I can ask him directly about his cables?

I don’t have it sorry. Disappointingly he’s started putting sync strippers in all his cables rather than fixing the clean sync output directly.

[Milsancho]

PlayStation’s do not output clean composite sync so any clean sync PS cable you buy will be using a sync stripper.

Sure, I meant that if the sync stripper is placed in the SCART plug instead of the other end, it kind of defeats the purpose of using C-sync for the purest signals possible, since the whole cable itself is sync-on-composite-video (unless it’s sync-on-luma, which is better I guess, but that’s not specified anywhere).

Disappointingly he’s started putting sync strippers in all his cables rather than fixing the clean sync output directly.

Do you mean that he puts the circuit even in the cables which will be used on C-sync-ready consoles!? Contrarily to the one form your review, I believe mine are not like this, since I remember him explicitely asking me if I really had a non-PAL system. Since when is he doing this?

Does the Dreamcast (NTSC-J) output C-sync RGB? It doesn’t right out of the box, right?

[BuckoA51]

Sure, I meant that if the sync stripper is placed in the SCART plug instead of the other end, it kind of defeats the purpose of using C-sync for the purest signals possible, since the whole cable itself is sync-on-composite-video (unless it’s sync-on-luma, which is better I guess, but that’s not specified anywhere).

Sync strippers usually go on the SCART end, the purpose isn’t really to improve the picture as such, more for compatibility with hardware like Extron Crosspoint or XRGB3.

Do you mean that he puts the circuit even in the cables which will be used on C-sync-ready consoles!? Contrarily to the one form your review, I believe mine are not like this, since I remember him explicitely asking me if I really had a non-PAL system. Since when is he doing this?

Only since recently, I guess one too many of his customers plugged in a CSYNC cable to a PAL console.

I agree it sucks, the less crap in your cable the better really.

Does the Dreamcast (NTSC-J) output C-sync RGB? It doesn’t right out of the box, right?

Yes, pin 10 on the AV out is composite sync.

[Milsancho]

Sync strippers usually go on the SCART end, the purpose isn’t really to improve the picture as such, more for compatibility with hardware like Extron Crosspoint or XRGB3.

Seems so… Still, if putting it on the console end could have the effect of also improving the signal, even if just theoretically, it’s hard to understand that nobody comes up with this solution. I now want to think that all these cables at least carry sync-on-luma before it’s splitted, in which case I guess it’s really as good as anything.

Yes, pin 10 on the AV out is composite sync.

Ah, thanks. A safe 75 Ohm, 3 V, perhaps? Are Playstations’ RGB fine in this regard too? After a bit of research, seems indeed that the Saturn NTSC outputs TTL, much like the MD/GEN. I really need to ask The Foo about his.

[BuckoA51]

Seems so… Still, if putting it on the console end could have the effect of also improving the signal, even if just theoretically

If clean sync is available from the console I’d typically want to use that simply because there is less chance of cross talk. Theoretically at least a well constructed cables should be able to use composite video for sync and not have any cross talk, but why leave it to chance. Supposedly fully shielded/grounded SNES cables have still shown issues on my setup when using composite video for sync.

However if the conosle doesn’t output clean sync, luma for sync is almost always as good, unless you specifically need clean sync for something like an XRGB3 (composite video for sync processing is bugged in B1 mode) or Extron Crosspoint (only accepts clean sync)

Ah, thanks. A safe 75 Ohm, 3 V, perhaps? Are Playstations’ RGB fine in this regard too?

No clean sync output on PlayStation 1 or 2, use luma instead. Not 100% sure on the Dreamcast’s sync output either.

The whole TTL vs 75ohm thing wasn’t well known about until recently. A lot of monitors/TVs will accept and work with TTL sync even if it’s outside spec, though it’s potentially causing additional wear and tear on your equipment. People really started using clean sync a few years ago with XRGB3s and also because it cleaned up dot crawl etc on some TVs/processors.

[Milsancho]

I’ve been using RGB systems since the 80’s. Japanese Saturn on RGB TVs, assuming that’s TTL, since mid-90’s. I never noticed a single issue due to this, some of those TVs are still working. And you see, it’s nowadays, 20-30 years later, I’m learning about the different sync cable modes, not to mention TTL, voltage, etc. Good thing sites like this exist. (The bad one is I’m not sure what to do with my Extron interface, now I know that there’s not a safe way to plug it into a TV set…)

[BuckoA51]

Is the Extron interface confirmed as outputting TTL sync? Documentation I’ve seen is conflicting. I will look into this when I get a chance.

[Milsancho]

Not sure. We discussed it here:

Extron RGB interfaces and cables

…and it seems it’s not TTL, but 5 V. I don’t know which one is worse for a TV set. Anyway, I need to get myself an UMSA once and for all. Hopefully that’s enough for the output side.

[BuckoA51]

Yes I remember, information on Extron’s datasheets seems a little conflicting. I thought with something like a Crosspoint it’d output sync at whatever voltage was input. I’ll have to get a multi-meter on one and see.

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