DB-15 to RCA cable for Extron switch

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bobrocks95
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DB-15 to RCA cable for Extron switch

Post by bobrocks95 »

I got a very nice Extron VGA switch for cheap in lieu of a SCART switch which aren't really available here and have all sorts of quality concerns. I'm not 100% sure I can feed 240p through it, but I've seen people use VGA switches in their setups before, so I'm willing to give it a shot- it's not doing any processing after all, should just be a straight digital switch.

Anyway, now I need a way to hook it up to my SCART converter. I have a SCART to 4 RCA RGBs adapter, so either DB-15 to RCA or DB-15 to SCART is needed (does that even exist?).

They're somewhat hard to find, but I have no clue what to choose- anything listed on Amazon or other places with reviews is full of people thinking it would convert to YPbPr and rating it 1 star.

These I see the most places and are supposedly Python brand cables, whoever Python are. They look nice, but thicker doesn't automatically mean better.

Then there are a couple odd ones found on ebay, not counting bottom of the barrel Chinese cables that I've ignored when I came across them
Ethereal
Calrad

Both are again brands I've never heard of and they're a bit pricier.

Has anybody gotten such a cable before or has any suggestions on what looks good? I don't really know what to look for in a cable at a glance.
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FinalBaton
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Re: DB-15 to RCA cable for Extron switch

Post by FinalBaton »

In your situation I would definitly go with a db-15 to 5 BNC cables, plus some of those tiny BNC to RCA plug adapters.

Reason why I say this, is because quality db-15 to 5 BNC cables are easyly available and cheap, because of their frequent use in computer hooking-up. I have two here that I bought from monoprice, just like these :
http://www.monoprice.com/product?p_id=566

the tiny adapters are a dollar each, so they won't break the bank :
http://www.monoprice.com/search/index?k ... bnc+to+rca

Maybe the cables you linked are good, but I have no experience with them, so I can't say. I can tell you though that the cables I mentionned above are solid.
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Fudoh
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Re: DB-15 to RCA cable for Extron switch

Post by Fudoh »

You will likely need clean sync from your sources to pass a 15khz RGBs signal through your Extron.
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bobrocks95
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Re: DB-15 to RCA cable for Extron switch

Post by bobrocks95 »

FinalBaton wrote:In your situation I would definitly go with a db-15 to 5 BNC cables, plus some of those tiny BNC to RCA plug adapters.

Reason why I say this, is because quality db-15 to 5 BNC cables are easyly available and cheap, because of their frequent use in computer hooking-up. I have two here that I bought from monoprice, just like these :
http://www.monoprice.com/product?p_id=566

the tiny adapters are a dollar each, so they won't break the bank :
http://www.monoprice.com/search/index?k ... bnc+to+rca

Maybe the cables you linked are good, but I have no experience with them, so I can't say. I can tell you though that the cables I mentionned above are solid.
BNC with a specific endorsement sounds good to me. An extra ~$4 is fine at that price.
Fudoh wrote:You will likely need clean sync from your sources to pass a 15khz RGBs signal through your Extron.
Good to know. I usually go clean sync with everything- guess I'll have to do something about the PS1 though.
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Guspaz
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Re: DB-15 to RCA cable for Extron switch

Post by Guspaz »

If it's just the display that needs csync, you can get a PS1 RGB cable with a sync stripper built-in. RGC charges an extra £10 for that on top of the regular cable. I believe that's cheaper than a sync strike or the LM1881 board that RetroRGB sells for $20 USD.

Of course, buying the LM1881 SCART board and adding it to your existing PS1 cable is probably cheaper than buying a whole new csync cable :P
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bobrocks95
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Re: DB-15 to RCA cable for Extron switch

Post by bobrocks95 »

Guspaz wrote:If it's just the display that needs csync, you can get a PS1 RGB cable with a sync stripper built-in. RGC charges an extra £10 for that on top of the regular cable. I believe that's cheaper than a sync strike or the LM1881 board that RetroRGB sells for $20 USD.

Of course, buying the LM1881 SCART board and adding it to your existing PS1 cable is probably cheaper than buying a whole new csync cable :P
My SCART adapter is fine with composite video and csync, but as Fudoh said it's likely the Extron switch will require csync.

I've asked retro console accessories on ebay if she has any DB-15 connectors (I've seen her sell a cable with one before), so I'd ask for a PS1 sync on luma cable with a sync stripper built in. I actually don't already have a PS1 cable so that's the better option.

As a side note I haven't had good luck with RGC so I may just have to make the cables myself... They don't sell DB-15 cables either so it'd be custom from them as well.
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Re: DB-15 to RCA cable for Extron switch

Post by Fudoh »

so I'd ask for a PS1 sync on luma cable with a sync stripper built in
if you have a stripper you don't need sync luma. If you feed luma or composite video into the stripper doesn't matter, the results will be identical.
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Re: DB-15 to RCA cable for Extron switch

Post by Guspaz »

Fudoh wrote:
so I'd ask for a PS1 sync on luma cable with a sync stripper built in
if you have a stripper you don't need sync luma. If you feed luma or composite video into the stripper doesn't matter, the results will be identical.
If that was the case, there would be no difference in quality between composite video sync and luma sync, which AFAIK is not the case...
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Re: DB-15 to RCA cable for Extron switch

Post by Fudoh »

there's a difference between composite video and luma for sync, because you're feeding the "dirty" sync directly into your display. A LM1881 will strip all the dirt (= picture information) away. That's the whole purpose of the IC.
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Re: DB-15 to RCA cable for Extron switch

Post by bobrocks95 »

Doesn't the display, assuming it accepts RGB, essentially have a sync stripper built in? The extra unneeded picture information is gotten rid of at some point, is it not?

My assumption was that the stripper would do a slightly better job with just luma than it would composite video- just like how comb filters can never really perfectly separate luma and chroma data, the LM1881 can't quite do a perfect job getting rid of picture data.

Or if the stripper is at the end of the cable opposite the console, there would be less interference along the cable with just luma running through.
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Fudoh
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Re: DB-15 to RCA cable for Extron switch

Post by Fudoh »

Doesn't the display, assuming it accepts RGB, essentially have a sync stripper built in? The extra unneeded picture information is gotten rid of at some point, is it not?
it's not used, but you're still routing it into the circuits, so you still get interference from the overlaying signal.

I mean, if you get a custom cable anyway, just order it with luma as sync if you like, but from my experience there's really no difference. The frequency range of the modulated color signals is likely far enough from the base signal to get effecively filtered.
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Re: DB-15 to RCA cable for Extron switch

Post by FinalBaton »

Guspaz wrote:If that was the case, there would be no difference in quality between composite video sync and luma sync, which AFAIK is not the case...
I think you're confusing composite video as sync with composite sync here
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Re: DB-15 to RCA cable for Extron switch

Post by Guspaz »

I'm not: sync-on-luma is not known for causing interference: it's what component video uses, and is not known to interfere (noise on component usually has other sources). Sync-on-composite-video, on the other hand, is notorious for causing interference...
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Re: DB-15 to RCA cable for Extron switch

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Guspaz wrote:I'm not: sync-on-luma is not known for causing interference: it's what component video uses, and is not known to interfere (noise on component usually has other sources). Sync-on-composite-video, on the other hand, is notorious for causing interference...
Oh. I was refering to Fudoh's point that if you have a stripper in the chain (wich Bob will need), then it won't matter if your cable carries composite video as sync or luma sync; you'll end up with composite sync any way with a stripped signal.

I misunderstood what you were saying. Of course your point above is true. Carry on!
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bobrocks95
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Re: DB-15 to RCA cable for Extron switch

Post by bobrocks95 »

Fudoh wrote:
Doesn't the display, assuming it accepts RGB, essentially have a sync stripper built in? The extra unneeded picture information is gotten rid of at some point, is it not?
it's not used, but you're still routing it into the circuits, so you still get interference from the overlaying signal.

I mean, if you get a custom cable anyway, just order it with luma as sync if you like, but from my experience there's really no difference. The frequency range of the modulated color signals is likely far enough from the base signal to get effecively filtered.
Got it, both things you said make sense. I'll go luma for piece of mind, but it makes sense now why it likely wouldn't matter.

Just waiting to hear back from RCA now...

EDIT: One final question I almost forgot about- I don't suppose light guns that use a T-connector can use a csync signal? I doubt it, but I've never used one and don't know exactly how they work; not sure if they use composite video just to do a time calculation from sync or if it directly looks at image data in some way.

EDIT2: Actually looking at this teardown The Guncon has a sync stripper built-in anyway, and reading more the photodiode just reacts when the phosphor wherever you're aiming brightens, so it sounds like csync would be fine.
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Re: DB-15 to RCA cable for Extron switch

Post by bobrocks95 »

Just wanted to do a slight necro bump to report that the Extron switch works great with 240p/480i content, auto-switches properly and everything, and the VGA to BNC cable FinalBaton recommended was a good choice.

Considering I bought the switch for just about $40 shipped, I'd say it's a great option compared to scarce, expensive, or questionably built SCART switches, at least from a North American perspective.
I placed a custom order from retro_console_accessories for the cables and they were only a couple dollars more each compared to her SCART cables too.
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