BA6592F/S-ENC Questions

what are the best video outputs for this encoder? ive read that it does not do RGB but composite and so YPbPr is a option and also that some prefer to use external amps for it aswell is there a sharp clear mod or dare say amp that i can install that doesnt involve the need for being external?

System in question to this is a SHVC-CPU-01 SNES launch model

Chris

 

It does indeed output RGB in addition to S-video and composite.

 

From my experience so far the component mod is not perfect. Colors are a bit off, especially yellow. I tried to tweak this mod in many ways and I still cant get it right.
I have not tried on a SHVC though.

 

I've had the same experience with it being too yellow. I have a Super Famicom with a BA6594AF chip.

 

The yellow is too weak here on GPM-02 S-enc.
Gold colors and orange are washed out compared to S-video and RGB.
At the same time there is a slight pink/purplish tint.

 

Is yours a BA6592F or BA6594AF?

What is going into the encoder chip? Can those signals be adjusted to fix the component output? I can imagine its close to (if not) impossible to fix some color issues with a difference color format like YPbPr...

 

It's S-ENC in a GPM 02, I do not know what encoder it is in truth.
The encoder uses RGB input.
Maybe the result would be better with more gain on PrPb color channels. The simple transistor amp does not seem to be enough. If I lower Luma, the yellow appears better, but the image is darker.
So boosting colors instead might help. I have not tried with a dedicated video amp IC yet.

 

so would a amp like the CXA amp for Neogeo/Genny's help or would it prolly not help the colors come out right?

 

I think what would get the best results would be to tweak the RGB levels before they're encoded into YPbPr. (I.e. tweaked before passing through the encoder chip) If a specific color is off, I feel like it would be close to inpossible to correct it, without affecting other colors, after its been encoded to YPbPr.

Also, as stated above, the original model Super Famicom/Super NES does natively output composite, s-video and RGB through its multi out connector. Early versions of the console, with the S-ENC chip, can be easily modified to output component (YPbPr) video by tapping pins on the encoder chip.

 

1) Color problems are certainly due to an improper driver (output amplifier) circuit rather than color matrix error, since it would subsequently affect composite video. Anyways tweaking RGB inputs will affect all colors using that color component so it's impossible to compensate with a passive circuit before OR after encoding, and an active circuit for the task would be out of the question.

2) AFAIK all SFC/SNES consoles all have high impedance RGB outputs, meaning technically they all are unsuited to driving a TV/monitor without an active RGB cable (such as the official SCART one).

The easiest way to proper RGB/YPbPr outputs is a video amplifier.

 

Over At NesDev Pasky tried with a dedicated video amplifier and he is the one who originally complained about the weak yellow/orange of the video circuit, which the video amp IC apparently did not fix.
I have also observed this using a transistor amplifier setup similar to what the others are doing. I tried tweaking it many ways but nothing seems to fix the weak yellow.

I compared with the same SNES on the Same PVM Composite, S-video, Component and RGB. And there is definitely a yellow/orange weakness compared to the other outputs. Interestingly, Composite is more orange than all the others.

I used the Map of the third world in DK country. Which has a sunset in it. There is a nice golden tint to the sun in composite. It is still there in s-video and RGB but with the component mod the sun looked pale and washed out.

I tried contacting Pasky about it in PM two weeks ago but he has not read the PM yet...

 

Of course adjusting the RGB inputs would affect all outputs, not just the YPbPr, but it would help if that's all you're going for, right? To me, personally, this is at best an interesting hack/mod, and a better solution (if you're looking for good YPbPr output) would be to build a dedicated encoder that separately taps the RGB. Then the original outputs are preserved.

I find it interesting that apparently, weak yellow is a common problem with this setup. I have exactly the opposite problem-- my output is too yellow...

 

Either it's your TV using a HD color matrix instead of SD, or it's a problem with "mod" circuit, or lack thereof...

 

It is possible that the Encoder output and/or associated circuitry differs from one version of the SNES to the other. That might explain why the Yellow weakness i am observing does not happen to everyone.

 

Just did this mod last night on my SHVC-01 1990. Everything looks washed out.

 

now have a unique prolem one of my two SNES's is showing RED in place of the color BLACK when played any idea's as to why this is happening ive taken this past month looking it over for messed up traces bad caps and faulty connections any idea's are much appreciated used a volt meter for my testing

 

Does this happen with every video signal type? If you can try pure RGB as this bypasses the encoder and would rule that out.