Any way to improve composite from NES?

[kamiboy]

Disregarding RGB mods or quality comb filters and focusing on just bettering the standard composite signal coming from the stock NES PPU, are there any known mods to improve the video quality?

I know disabling the RF unit could potentially reduce noise, but is there anything else?

Any benifits to tapping the composite directly from the PPU?

Is it the PPU that does the NTSC signal shifting thing that causes things to look very coarse when they move, but fine when static? I suspect that it is, but if not then tapping the signal directly from the PPU could potentially net a better looking signal.

I have two original model NTSC/U NES' here and wouldn't mind performing some mod experiments on one of them, just need to know what to do.

[Fudoh]

when I sourced my AV famicom and my US NES for RGB modding last year, I found that the the AV famicom's picture quality was quite nice compared to the US front loader NES. Is this common knowledge ?

I can understand that somebody doesn't want to do the RGB mods, but what do you have against a quality comb filter ? Modding a NES with an internal Texas Instrument 5-line comb filter would be AWESOME!

[kamiboy]

Nothing against comb filters, I just wanted to know if there is any improvements to be done before we get to the filtering. I mean, the better a signal you feed a comb filter the better video you get out.

What is this TI internal filter of which you speak? Is it cheap and easy to come by? I m guessing no.

Also, I didnt know that AV Famicoms were better at composite than a regular NES-001.

[Fudoh]

I wasn't able to do NES vs. AV Famicom anytime close, but while the US NES looked quite mediocre on the Framemeister, I was surprised about how "acceptable" the japanese one was looking.

The TI comb filter is just an IC. I don't know anything about it's price, maybe a few $, but you probably can't get them without ordering larger quantites (on the other hand, maybe a sample order ?), here's a spec sheet: http://www.datasheetcatalog.org/datashe ... 565_DS.pdf

[kamiboy]

Am I misunderstanding the specs or does this put out a 480p YUV signal. I want 240p in 240p out.

[Fudoh]

it's a comb filter. it does nothing to the signal. 240p in, 240p out if you like. It's just COMPATIBLE with 480p input signals, which makes it easier for manufacturers to integrate.

[kamiboy]

You can buy the lone IC for a paltry sum on ebay, but it seems this is far from a plug and play device. The spec sheet keeps talking about digital video output and control registers. Using something like this is way above my head.

[Fudoh]

absolutely. You would need a complete circuit board, but nevertheless IT WOULD BE NICE so see something like this happening. That is if the HDMI NES should not be able to handle the composite palettes nicely.

Here's a thread which seems to confirm that the AV famicom has the best composite quality:
http://www.nintendoage.com/forum/messag ... adid=76983

[Ex-Cyber]

Have you already looked at amplifier mods? ISTR some discussion to the effect that the composite video amp in the NES is a dirt-cheap discrete transistor amp that is known to crapify the signal. Maybe replace it with a nice op-amp circuit and see what happens? There are probably already some schematics floating around out there, maybe on benheck.com or nesdev.com.

Is it the PPU that does the NTSC signal shifting thing that causes things to look very coarse when they move, but fine when static? I suspect that it is, but if not then tapping the signal directly from the PPU could potentially net a better looking signal.

I think that does come from the PPU design, but I don't specifically recall which quirk it is.

[Fudoh]

semi on-topic: just tried an unmodified PAL NES on the XRGB-Mini (through composite) and it looks *very* nice. Definitely much better than both NTSC versions I tried a few months ago*. With the slightly softening 576p output by the Mini, it's hard to see any false contures and hardly any dot crawl. Of course you still get some kind of "background" movement, but it's definitely the best I've seen yet for a PAL NES. Anybody with a Mini and a PAL NES should give it a try.

(*which is especially interesting, since normally the PAL NES's composite output really doesn't shine).

[kamiboy]

My end purpose is a PVM CRT, but I've long been wanting to do a side by side of a PAL and NTSC NES to see which fares better on a PVM. If I can be arsed to fish out my PAL NES and two copies of Mega Man 2 I'll get it done one of these days.

[kamiboy]

Have you already looked at amplifier mods? ISTR some discussion to the effect that the composite video amp in the NES is a dirt-cheap discrete transistor amp that is known to crapify the signal. Maybe replace it with a nice op-amp circuit and see what happens? There are probably already some schematics floating around out there, maybe on benheck.com or nesdev.com.

Not surprisingly all my searches only netted me NES composite amps for the 101 which never had composite to begin with.

[daskrabs]

http://amoddinghomecompanion.blogspot.c ... esome.html

I put this together a while back. I should put some more recent images up since my rig has changed a bit, but I still stand by the FC-10D.

[kamiboy]

Your PVM is a 2530, isn't it?  I had one once, the composite input was abysmal. That is why I bought a Kramer myself. Alas my current PVM perform excellently via composite, much better than the kramer, but NES composite still looks rather subpar.

There are better Comb filters out there but I am more interested in what can be done to improve composite quality with the NES hardware itself. 

[Greg2600]

absolutely. You would need a complete circuit board, but nevertheless IT WOULD BE NICE so see something like this happening. That is if the HDMI NES should not be able to handle the composite palettes nicely.

Here's a thread which seems to confirm that the AV famicom has the best composite quality:
http://www.nintendoage.com/forum/messag ... adid=76983

Yeah I think Nintendo began to use better hardware when they rolled out the AV Famicom and NES Top Loader. Probably the same as in the SNES, which has excellent composite/S-video.

[daskrabs]

Your PVM is a 2530, isn't it?  

I have a 3230 now. Same crappy composite. I have several other PVMs as well. None of them do composite worth a damn. The comb filter isn't perfect, but good enough for now.

[kamiboy]

I have a 3230 now. Same crappy composite. I have several other PVMs as well. None of them do composite worth a damn. The comb filter isn't perfect, but good enough for now.[/quote]

Unlike the PVM models from the 80's and 90's the ones constructed in the 2000's have excellent composite input quality. I have an L2 and L5 and they perform very well, if not better than another of my previous displays, the NEC XM29 which worked wonders on the NES composite.

On a screen where nothing moves composite from the NES looks like S-video or RGB. It is very vibrant and sharp. Alas as soon as the screen starts to scroll you get artefacts that reveal the nature of the source.