Re: YPbPr ouput mod for SNES consoles
Posted: Sat Jan 11, 2014 9:26 pm
NightWolve, when you measure component values, are you removing the components or just putting the probes to them while in the circuit?
NES Development and Strangulation Records message boards
So you were asking me about this (I was actually in the middle of answering you when you made your 2nd post):blargg wrote:I have a specific question for the person who measured all the component values to map out the SNES video output circuitry (which BTW is a very good step to become more grounded in reality). Did you desolder the components before measuring, or just measure them as soldered in the circuit? ... NightWolve, when you measure component values, are you removing the components or just putting the probes to them while in the circuit?
Honestly, save your time and money and disregard this mod. I wish I had. I know the SNES directly outputting YPbPr seems awesome, but if functionality is all you're after, an external device is a better option in my opinion.SkinnyV wrote:I was revisiting this page but still not sure if any circuit is now considered the correct one to use. Which one is now deemed the optimal one? I read almost all the pages but still not sure since most of the posts are about adding a removing a part by trial and error or why the previous amp is wrong. I'm looking at trying it on my snes.
Well now, lemme be the first to thank you for all of your contributions to this thread, and most especially this latest and very, very curious one right here... I think, however, it would strike some, myself included, as a little, oh, I dunno, racist, RACIST, RACIST!!! As to the content, that's also curious, your attempt to generalize me (and still from a position of arrogance), either from just this encounter or I wonder perhaps because you also had a hard-on for me before I even got here; it did make me wonder, but no matter.kyuusaku wrote:http://i.imgur.com/dMxyX9o.jpg
Could be, but I think the reason(s) for it is on the top of the motherboard, the manufacturer usually goes cheap with aluminum electrolytic capacitors, while on the bottom (less accessible) they go expensive with tantalums, and aluminums come in their standard (or "preferred") sizes, going from 100 uF to 220 uF. In general aluminum cap kits, there's no solid 200 uF cap, so the only way to get that value if you really don't wanna use a solid 220 uF, is to take two 100 uF caps and solder 'em up in parallel. You can find ANY size I believe if you shop at places like mouser.com/digikey.com, but with general aluminum capacitor kits, yeah, you won't see a solid 200 uF. Anyway, I'm a layman in this, so just an observation.blargg wrote:Thanks, that helps the schematic, which is valuable to have with the confirmed component values. You might notate two 100uF caps in parallel on the schematic, because non-capacitance aspects might be the reason for the pair (ESR for one). I'm pretty ignorant on that but it could be important information.
I wouldn't say we reached an "optimal" or "most correct" one just yet, really. But you have multiple options, so depends what you want.SkinnyV wrote:I was revisiting this page but still not sure if any circuit is now considered the correct one to use. Which one is now deemed the optimal one?
Well, to this I would ask, how many CRT TVs in your lifetime with both S-Video and YPbPr have you observed this finding and thus base this generalization from ? 3 ?? 5 ?? 10 ??Ziggy587 wrote:From my own personal findings, YPbPr offers no visual improvement over S-Video on a CRT TV. And no, I DON'T mean that as an end-all statement for everything, but that has been my experience with retro consoles. If you're gaming on a CRT, just stick with S-Video where possible. Forget about YPbPr entirely.
I'm surprised you saw shimmering during scrolling. I don't understand how that's even possible, unless the TV internally just mixed the S-video into composite before processing.NightWolve wrote:When it comes to my 32" Panasonic CRT TV with both S-Video and YPbPr, the YPbPr inputs are clearly far superior. The picture is sharper, there's less color bleed, and there is a lot less shimmering than with S-Video when there is scrolling/motion, etc.
Hence, if true, you'll want to use your YPbPr connections more times than not! In other words, the circuitry of the YPbPr processing is cleaner/better, while the S-Video circuitry might be pretty shitty on some TV brands, etc. This is all talking about the same TV that has both S-Video and YPbPr mind you, etc. Not comparing a Sony TV using S-Video and a shitty brand using YPbPr and saying, hey, the Sony looks better! That's not a fair comparison.S-Video is a type of Component and should perform close.
It does depend on how the TV implemented it.
If the TV mixes S-Video to Composite first, it will look like Composite.
If the TV processes the Luma and Chroma separately it should be really sharp.
Enough, but if you want a honest answer, 3 CRTs plus 2 HDTVs. Most of the comparison was done on my Sony Wega KV27FS120 (CRT) and my Samsung LN40E550 (HDTV).NightWolve wrote:Well, to this I would ask, how many CRT TVs in your lifetime with both S-Video and YPbPr have you observed this finding and thus base this generalization from ? 3 ?? 5 ?? 10 ??
Sounds like your TV sucks.NightWolve wrote:When it comes to my 32" Panasonic CRT TV with both S-Video and YPbPr, the YPbPr inputs are clearly far superior. The picture is sharper, there's less color bleed, and there is a lot less shimmering than with S-Video when there is scrolling/motion, etc.
You should consider picking up a Sony Wega. The one I have, composite looks amazing (compared to composite on other CRTs). I've never seen an NES look so good on a CRT before. In fact, composite looks so good on this TV, it led to some confusion. I had to pull apart my SNES composite/s-video cable to confirm that it was wired for true s-video and not just composite over S-video (as I've read some do).NightWolve wrote:Composite of course is just plain horrible once you see the differences, and add in the dot crawl effect, etc.
Minus a bit for horizontal blanking; the active scanline is 52.148 microseconds long. There is actually 7.16 MHz of bandwidth on the chroma carrier (DC to twice color burst). And though AM uses twice the bandwidth of baseband, reducing modulator bandwidth to 3.58 MHz, QAM fits two channels (U and V) onto the same frequency. So you end up with 3.58 MHz bandwidth for U and 3.58 MHz for V. Now the Nyquist theorem states that a bandwidth of R corresponds to a sample rate of 2R. Thus 3.58 MHz bandwidth means 7.16 MHz sample rate, or 373 samples per active scanline.lidnariq wrote:In any case, 3.6MHz of bandwidth will only provide 227.5×¾, or about 171 visible chroma periods per scanline.