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 Post subject: Re: How to Determine TTL Sync
PostPosted: Sat May 01, 2021 2:49 pm 


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maxtherabbit wrote:
C-sync and TTL are not mutually exclusive terms. You keep saying "csync or TTL" like they are

C-sync refers to the *type* of sync (composite sync meaning horizontal and vertical sync combined (not to be confused with sync on composite video))

TTL refers to the *amplitude* of the sync signal, its lower voltage counterpart is "video level sync" AKA 75 ohm sync


Ok so it's not CSync it's 75 Ohm sync? Gotcha.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Sat May 01, 2021 3:16 pm 


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I decided to get brave and crack open some of my SCART cables. I apologize in advance for the crappy pictures, but they're not an easy area to get to so I had to make due with a crappy phone and a flashlight. Hopefully these pictures can help determine if they have the correct resistors and capacitors to get 75 Ohm sync.

Genesis Model 2 - Looks like there's just one resistor and nothing else
Image

SMS - Looks like three resistors on the RGB lines and another one across some pins
Image


SNES - Looks like three caps and a resistor
Image


NES (RGB modded) - Same as the SNES one.. Three caps and a resistor
Image


Can we tell anything from these pictures? If so I can crack open the rest of my cables and take pictures. I appreciate all the help everyone has been giving me so far.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Sat May 01, 2021 5:54 pm 


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Is the color code on those resistors Green, Black, Orange, Red? 4 total, in that order? Hard to make it out.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Sat May 01, 2021 7:25 pm 


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Josh128 wrote:
Is the color code on those resistors Green, Black, Orange, Red? 4 total, in that order? Hard to make it out.

I think so, I'd have to open it again to be sure. What should they be? I have a better quality picture somewhere.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Sat May 01, 2021 7:41 pm 


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Location: Montréal, Canada
Tempest_2084 wrote:
maxtherabbit wrote:
C-sync and TTL are not mutually exclusive terms. You keep saying "csync or TTL" like they are

C-sync refers to the *type* of sync (composite sync meaning horizontal and vertical sync combined (not to be confused with sync on composite video))

TTL refers to the *amplitude* of the sync signal, its lower voltage counterpart is "video level sync" AKA 75 ohm sync


Ok so it's not CSync it's 75 Ohm sync? Gotcha.


No.

csync 75ohm
csync TTL

These are both two things that exist. There is 75ohm csync and TTL csync.

Look at it another way: csync just means there's no video signal riding along, it tells you nothing about what kind of sync it actually is.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Sat May 01, 2021 9:58 pm 


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Guspaz wrote:
Tempest_2084 wrote:
maxtherabbit wrote:
C-sync and TTL are not mutually exclusive terms. You keep saying "csync or TTL" like they are

C-sync refers to the *type* of sync (composite sync meaning horizontal and vertical sync combined (not to be confused with sync on composite video))

TTL refers to the *amplitude* of the sync signal, its lower voltage counterpart is "video level sync" AKA 75 ohm sync


Ok so it's not CSync it's 75 Ohm sync? Gotcha.


No.

csync 75ohm
csync TTL

These are both two things that exist. There is 75ohm csync and TTL csync.

Look at it another way: csync just means there's no video signal riding along, it tells you nothing about what kind of sync it actually is.


Ok I think I understand now. I just wish there was an easy way to tell what my cable is doing. I guess even looking at the inside of the SCART head doesn't help all the time because the needed components might be in the console plug side of the cable. I think I'm just going to assume all my cables are 75ohm csync and take my chances with the 5X Pro.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Sun May 02, 2021 1:23 am 


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Tempest_2084 wrote:

Ok I think I understand now. I just wish there was an easy way to tell what my cable is doing. I guess even looking at the inside of the SCART head doesn't help all the time because the needed components might be in the console plug side of the cable. I think I'm just going to assume all my cables are 75ohm csync and take my chances with the 5X Pro.


While there's obviously no guarantee, I think the main cable makers that everyone goes to have been doing the 75ohm cables over the last few years. I think you'd only have gotten TTL if you specifically asked for it.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Sun May 02, 2021 1:37 am 


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TooBeaucoup wrote:
While there's obviously no guarantee, I think the main cable makers that everyone goes to have been doing the 75ohm cables over the last few years. I think you'd only have gotten TTL if you specifically asked for it.

I'm thinking the same thing.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Sun May 02, 2021 7:42 am 


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Location: Honolulu, Hawaii
Tempest_2084 wrote:
Ok I think I understand now. I just wish there was an easy way to tell what my cable is doing. I guess even looking at the inside of the SCART head doesn't help all the time because the needed components might be in the console plug side of the cable. I think I'm just going to assume all my cables are 75ohm csync and take my chances with the 5X Pro.


I'd be willing to bet that your cables all use composite video for sync. That's how the SCART standard was designed - its primary purpose was to display composite video, with the RGB lines as a way to add closed captioning or other overlays. Using SCART to display pure RGB video is kind of a hack and there's no reason for a standard European SCART cable to use csync.

None of your cables have an inline resistor on pin 20, which is what would be necessary to attenuate your consoles' sync signal to 75 ohm levels. The resistor that all your cables have is for the blanking voltage, which is what tells a PAL television to switch to RGB instead of composite (this is a remnant of SCART RGB's close caption origins). The resistors on the SMS cable are on the RGB lines, rather than the sync signal.

Looking at the photos of your cables, they are all low end cables with no shielding. These cables are made in Asia and were designed for low budget PAL television owners, not tech savvy retro gamers with fancy scalers and pro monitors. I've never seen a cable like this that was wired for Csync. While they are not the best cables in the world, they should work fine for your purposes and you should be fine using them with your Retrotink.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Sun May 02, 2021 7:56 am 



Joined: 01 Jul 2017
Posts: 159
matt wrote:
Tempest_2084 wrote:
Ok I think I understand now. I just wish there was an easy way to tell what my cable is doing. I guess even looking at the inside of the SCART head doesn't help all the time because the needed components might be in the console plug side of the cable. I think I'm just going to assume all my cables are 75ohm csync and take my chances with the 5X Pro.


I'd be willing to bet that your cables all use composite video for sync. That's how the SCART standard was designed - its primary purpose was to display composite video, with the RGB lines as a way to add closed captioning or other overlays. Using SCART to display pure RGB video is kind of a hack and there's no reason for a standard European SCART cable to use csync.

None of your cables have an inline resistor on pin 20, which is what would be necessary to attenuate your consoles' sync signal to 75 ohm levels. The resistor that all your cables have is for the blanking voltage, which is what tells a PAL television to switch to RGB instead of composite (this is a remnant of SCART RGB's close caption origins). The resistors on the SMS cable are on the RGB lines, rather than the sync signal.

Looking at the photos of your cables, they are all low end cables with no shielding. These cables are made in Asia and were designed for low budget PAL television owners, not tech savvy retro gamers with fancy scalers and pro monitors. I've never seen a cable like this that was wired for Csync. While they are not the best cables in the world, they should work fine for your purposes and you should be fine using them with your Retrotink.


Good eye and yup those look like Alibaba specials with composite video sync, which is technically correct but sadly no shielding. Will work just fine with the 5x.. maybe with some noise and hum compared to the good stuff but still far better than composite. I say use them and play the damn game for now.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Sun May 02, 2021 1:09 pm 


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mikechi2 wrote:
matt wrote:
Tempest_2084 wrote:
Ok I think I understand now. I just wish there was an easy way to tell what my cable is doing. I guess even looking at the inside of the SCART head doesn't help all the time because the needed components might be in the console plug side of the cable. I think I'm just going to assume all my cables are 75ohm csync and take my chances with the 5X Pro.


I'd be willing to bet that your cables all use composite video for sync. That's how the SCART standard was designed - its primary purpose was to display composite video, with the RGB lines as a way to add closed captioning or other overlays. Using SCART to display pure RGB video is kind of a hack and there's no reason for a standard European SCART cable to use csync.

None of your cables have an inline resistor on pin 20, which is what would be necessary to attenuate your consoles' sync signal to 75 ohm levels. The resistor that all your cables have is for the blanking voltage, which is what tells a PAL television to switch to RGB instead of composite (this is a remnant of SCART RGB's close caption origins). The resistors on the SMS cable are on the RGB lines, rather than the sync signal.

Looking at the photos of your cables, they are all low end cables with no shielding. These cables are made in Asia and were designed for low budget PAL television owners, not tech savvy retro gamers with fancy scalers and pro monitors. I've never seen a cable like this that was wired for Csync. While they are not the best cables in the world, they should work fine for your purposes and you should be fine using them with your Retrotink.


Good eye and yup those look like Alibaba specials with composite video sync, which is technically correct but sadly no shielding. Will work just fine with the 5x.. maybe with some noise and hum compared to the good stuff but still far better than composite. I say use them and play the damn game for now.


Thank you all for the info. I feel better now, but I think probably should upgrade. What brand/company do you all recommend for cables? I know HD Retrovision gets high praise, but they're all component cables. Who makes the best SCART cables? Well at least good quality ones that don't run $70+ :)

It looks like Retro Access has a new line of cheaper fully shielded cables called Fortaflex. I think these might work for what I want:

https://retro-access.com/collections/fortraflex

I assume all my consoles will work with 75 Ohm csync? Other than my NES (the first RGB mod that was created) and my TurboDuo (another early mod) none of them are modded with anything unusual.

EDIT: I have a ton of questions now. I think I might start a new thread since this no longer has anything to do with TTL Sync.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Mon May 03, 2021 4:40 am 


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Retro acces cables are easily the best quality you can buy, but it's overkill for 90% of gamers. Their fortraflex cables will definitely be good enough. IMO Insurrection is your best bet; their stuff is well made, affordable, and most importantly it's usually in stock.

If your cable is properly shielded, there's no need to use csync unless you have a device that requires it, such as an Extron unit or an old computer monitor.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Mon May 03, 2021 12:13 pm 



Joined: 01 Mar 2018
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matt wrote:
Retro acces cables are easily the best quality you can buy


Not if you bought them in 2018. I think I bought 7-8 of the highest quality cable from them and had issues with 3 of them. Mostly bad soldering on the inline resistor, but unless the quality has improved in 3 years...


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Mon May 03, 2021 1:10 pm 


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matt wrote:
IMO Insurrection is your best bet; their stuff is well made, affordable, and most importantly it's usually in stock


Yeah I was thinking about going with them as long as their cables were decent. Bob seems to think they were ok and almost indistinguishable from the Retro Access ones in terms of picture/audio quality. While I want good quality cables, I'm not going to zoom in 500 times and inspect each pixel. I'm honestly more concerned about audio buzz and highly noticeable fringing/interference patterns than anything else.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Mon May 03, 2021 4:39 pm 


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Being the masochist that I am, I decided to open up my two cables that go from one scart switch to the other and the one that goes to my TV. These cables are a bit odd as they appear to have a loose pin wired that gets wedged in between the metal shielding and the SCART connector itself (it popped out when I took the picture). I assume this is for ground, but what a weird way to do it. They look like the typical cheap thin gauge wires, but they appear to have *some* shielding in the actual cable itself. Are these cables crap as well? Should they be replaced? I'd hate to upgrade the rest of my cables and have them do no good because the final cable is crap.

Here's a picture of it (ignore the lovely finger, I had to try and hold it together while taking the picture)
Image


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Tue May 04, 2021 2:21 am 


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That loose pin is just a way to connect the shell (aka pin 21) to ground.

The real test of whether or not a cable is good enough is to try it in your setup. That cable does have some external shielding, but there's still the potential for interference between the video and audio lines. Once you get your 5x, try your consoles with and without the switcher and the intermediate cables and you should be able to figure out if there's enough signal degradation for it to be a problem.


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 Post subject: Re: How to Determine TTL Sync
PostPosted: Tue May 04, 2021 2:57 am 


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Ok I'll wait for the 5X to get here before replacing this cable since it might actually be ok.


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