Are there any near lossless passive scart switch boxes?

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Taiyaki
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Are there any near lossless passive scart switch boxes?

Post by Taiyaki »

I use a gscartsw and love it, but I find 8 slots to be insufficient as I usually need 9, or 10 slots for everything to be neatly connected at once. Instead of just continually unplugging some in favor of others which is what I was doing, I was considering getting a 3 or perhaps 2 slot scart switch box. I'm thinking of passive because I have so many power cables and no more room on any of the already very largely populated surge protectors.

Has anyone tried any of those ones on ebay to see how much brightness gets lost when using them? I know cheap ones tend to also add noise which would be very undesirable, but if the loss if just a 10% drop in brightness I can compensate but increasing the contrast setting when using those consoles perhaps.
fernan1234
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Re: Are there any near lossless passive scart switch boxes?

Post by fernan1234 »

If you want to stick to SCART, I think this is the best switch option: http://www.axunworks.com/SCA101-RGB-SCA ... -p931.html
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Guspaz
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Re: Are there any near lossless passive scart switch boxes?

Post by Guspaz »

You could always chain a second gscartsw, the auto-switching still works :)
fernan1234
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Re: Are there any near lossless passive scart switch boxes?

Post by fernan1234 »

Guspaz wrote:You could always chain a second gscartsw, the auto-switching still works :)
:lol: This would be a good way to double his problems:
Taiyaki wrote: I'm thinking of passive because I have so many power cables and no more room on any of the already very largely populated surge protectors.
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NewSchoolBoxer
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Re: Are there any near lossless passive scart switch boxes?

Post by NewSchoolBoxer »

You can daisy chain one gscartsw into another but that would be expensive. When you say nearly lossless, no one going around doing signal to noise measurements on input and output of these things. Only Extron bothers to make a claim about noise. Is a 2017 video from My Life in Gaming where they compare passive and active switchers and sometimes the passive switcher has lowest loss. Most devices have brightness loss that you are correct can be compensated with the knob on CRT but sharpness loss not so much. Active switchers compensate for power loss from cable length and are necessary to split RGB but more chips and wiring mean more sources of noise: https://www.youtube.com/watch?v=998tBzpJhVo

Otaku-Games that ships from Hong Kong sells passive 6:1 and active 6:3 SCART switchers. I saw two Reddit comments about daisy chaining into gscartsw no issues: https://otaku-games.com/

Extron has an active CrossPoint Ultra 128 (12:8) matrix but forces you into BNC and Phoenix audio adapters: https://www.extron.com/product/crosspointultra128
Literally the only maker that states a claim about loss from cross talk (EMI from one cable radiating onto another). Numbers on right are bandwidth used:

-85 dB @ 1 MHz
-73 dB @ 5 MHz
-70 dB @ 10 MHz
-63 dB @ 30 MHz
-56 dB @ 100 MHz

Note that 600 MHz is from using all 8 outputs at once. The -56 dB is small indeed when -40 dB would certainly be under the noise floor for video and therefore invisible. The 12:12, 16:8 and 16:16 model are even more lossless. Read over the manual about sync since I think Extron RGB devices only accept csync, sync on green and rgbhv sync and output 4-5 Vp-p TTL sync. PVMs and RGB capture cards take TTL no issue.

Just in passing, be sure that you really need more than 8 inputs. Having everything connected neatly looks nice but you're adding cost for convenience.
Taiyaki
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Re: Are there any near lossless passive scart switch boxes?

Post by Taiyaki »

Thanks to all of you for the replies.
fernan1234 wrote:If you want to stick to SCART, I think this is the best switch option: http://www.axunworks.com/SCA101-RGB-SCA ... -p931.html
Wow that looks amazing. I wasn't aware that something had come out on the market that could potentially even top the gscartsw at a similar price point.
Last edited by Taiyaki on Thu Jan 28, 2021 4:57 am, edited 1 time in total.
Taiyaki
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Re: Are there any near lossless passive scart switch boxes?

Post by Taiyaki »

NewSchoolBoxer> Thanks for that greatly informative post.
RGB0b
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Re: Are there any near lossless passive scart switch boxes?

Post by RGB0b »

Taiyaki wrote:I use a gscartsw and love it, but I find 8 slots to be insufficient as I usually need 9, or 10 slots for everything to be neatly connected at once. Instead of just continually unplugging some in favor of others which is what I was doing, I was considering getting a 3 or perhaps 2 slot scart switch box. I'm thinking of passive because I have so many power cables and no more room on any of the already very largely populated surge protectors.

Has anyone tried any of those ones on ebay to see how much brightness gets lost when using them? I know cheap ones tend to also add noise which would be very undesirable, but if the loss if just a 10% drop in brightness I can compensate but increasing the contrast setting when using those consoles perhaps.
Oktaku has a cheap one that'll fit your needs perfectly: https://youtu.be/QiivayiBroc
That's an older review, so you'll definitely want to check this one out too for context: https://youtu.be/KeMPPyJAM_w
...don't get this one though, unless you're 100% sure of the cables you own: https://www.retrorgb.com/otaku-6in3out- ... eview.html
Using an Extron Crosspoint is a good solution too, but you'll need to convert all the cables to BNC and you can't use any cvbs or luma as sync cables without a sync stripper.
NewSchoolBoxer wrote:When you say nearly lossless, no one going around doing signal to noise measurements on input and output of these things.
Uhhh...maybe you should pay more attention to the reviews out there. That's EXACTLY what I did on the audio and video lines.
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NewSchoolBoxer
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Re: Are there any near lossless passive scart switch boxes?

Post by NewSchoolBoxer »

NewSchoolBoxer wrote:When you say nearly lossless, no one going around doing signal to noise measurements on input and output of these things.
Uhhh...maybe you should pay more attention to the reviews out there. That's EXACTLY what I did on the audio and video lines.[/quote]

That is not what you did. You subjectively looked at video on a PVM and listened to audio with a capture card since we know PVMs are weak on that front. You just eyeballed the oscilloscope readings in the time domain with no attempt to use the FFT function or anything like MATLAB on the computer. No use of root mean squared voltage. This is amateur level analysis with expert level equipment and cannot show which switchers have the lowest loss or interference when the measuring stick is none, a little or a lot. If looking at Component then should compare NTSC and PAL because of PAL alternating polarity on chroma's V that, in theory, resists interference.

The audio humming is easily seen in the frequency domain and lowers the signal to noise ratio for an objective measure of quality. Trick with signal to noise ratio is which reference video and audio to compare to for calculation. I think taking both directly from console output to capture card is fine and without any filtering or processing the PVM might do. Someone else might argue for using the digital RGB video and digital audio of an accurate emulator. I consider this expert level analysis for Game Boy Interface: https://www.gc-forever.com/wiki/index.p ... rd_Edition which demonstrates GCHD Mk-II + HD Retrovision and Datel GC Component cables are equal or better than Nintendo's infamously rare and expensive cable.

Unless I'm missing something, you also only looked at 240p/480i video. Many sources of noise are modeled by functions of the square root of the frequency. The jump to 480p basically doubles the horizontal sync frequency and bandwidth and quadruples the data rate. Same audio but devices that showed no video interference before can fail here. Using Extron + GC charts for lack of anything else, going from 6 to 12 MHz bandwidth drops video quality the difference between Component and S-Video. I don't own a CRT that takes 480p but my LCD monitor does. ADC process itself adds noise and brings up the desire for taking signal to noise ratio measurement to the next step of noise spectral density.

I know it doesn't sound like it but I'm the biggest fan of yours for all your scientific content, explanation of sync and showing how to measure signals and build useful circuits. A BS in electrical engineering didn't teach me what luma and chroma were. You're the best there is in retro gaming of anyone showing results with an oscilloscope or multimeter outside of the GBI cables and xeos' television lag testing. We can just raise the bar higher.
ldeveraux
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Re: Are there any near lossless passive scart switch boxes?

Post by ldeveraux »

NewSchoolBoxer wrote: That is not what you did. You subjectively looked at video on a PVM and listened to audio with a capture card since we know PVMs are weak on that front. You just eyeballed the oscilloscope readings in the time domain with no attempt to use the FFT function or anything like MATLAB on the computer. No use of root mean squared voltage. This is amateur level analysis with expert level equipment and cannot show which switchers have the lowest loss or interference when the measuring stick is none, a little or a lot. If looking at Component then should compare NTSC and PAL because of PAL alternating polarity on chroma's V that, in theory, resists interference.

The audio humming is easily seen in the frequency domain and lowers the signal to noise ratio for an objective measure of quality. Trick with signal to noise ratio is which reference video and audio to compare to for calculation. I think taking both directly from console output to capture card is fine and without any filtering or processing the PVM might do. Someone else might argue for using the digital RGB video and digital audio of an accurate emulator. I consider this expert level analysis for Game Boy Interface: https://www.gc-forever.com/wiki/index.p ... rd_Edition which demonstrates GCHD Mk-II + HD Retrovision and Datel GC Component cables are equal or better than Nintendo's infamously rare and expensive cable.

Unless I'm missing something, you also only looked at 240p/480i video. Many sources of noise are modeled by functions of the square root of the frequency. The jump to 480p basically doubles the horizontal sync frequency and bandwidth and quadruples the data rate. Same audio but devices that showed no video interference before can fail here. Using Extron + GC charts for lack of anything else, going from 6 to 12 MHz bandwidth drops video quality the difference between Component and S-Video. I don't own a CRT that takes 480p but my LCD monitor does. ADC process itself adds noise and brings up the desire for taking signal to noise ratio measurement to the next step of noise spectral density.

I know it doesn't sound like it but I'm the biggest fan of yours for all your scientific content, explanation of sync and showing how to measure signals and build useful circuits. A BS in electrical engineering didn't teach me what luma and chroma were. You're the best there is in retro gaming of anyone showing results with an oscilloscope or multimeter outside of the GBI cables and xeos' television lag testing. We can just raise the bar higher.
Damn!
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