Amiga and BENQ BL912 / BL702A Monitors

[turrican9]

I'm interested to hear what other people think about the BL702A connected with RGB to VGA compares to a CRT display using scart? Personally I will get rid of my CRTs.

[turrican9]

So my Amiga 500 and Amiga 600 are crystal clear on the BL702A using RGB to VGA adapter. My Amiga 1200 has a more blurry picture. Not horrible, but more blurry than my A600 and A500, both which shows crystal clear picture. This Amiga 1200 have an Indy AGA MK2 installed. Could the MK2 somehow affect the picture quality of the RGB? Thinking since it's installed on top of Lisa and that it draws some power from it. Is it worth trying to remove the AGA MK2 to see if I get a better picture (Like my A500 and A600 crystal clear picture) from the RGB?

Edit: btw, this Amiga 1200 was recapped before I bought it on ebay last year. I also inspected the motherboard and could see the the caps had fresh solder. Looked very professional.

[turrican9]

Solved my issue I think. First of all my Amiga 1200 was running 32 colours in Classic Workbench VS 16 colours on my A500 and A600. Turning it to 16 colours in the A1200 made the igame logo look yellow on the A1200, just like the A500/A600.

Also, it seems like A1200's RGB is outputting quite different from A500/A600. When I turned gamma from 3 to 5 and contrast from 50 to 70 on my BenQ BL 702A I pretty much got the exact same picture I have on my A500/A600 with Gamma at 3 and the contrast at 50. So now it looks perfect to me. I got the same level of blackness on the A1200 with gamma at 5 as I have in my A500/A600 with gamma at 3 on the same monitor.

I also read that Amiga 1200s RGB works through a video dac and does not output the exact same way the A500/A600 does? Anyway, I'm happy with the picture quality now.

Also, one of the reasons why I think the BenQ BL 702A is so good for Amiga use, appart from it handling 15KHz and 50Hz PAL with a nice picture is that this monitor has sharpness settings. At default it's set at 1, and this gives it free "anti aliasing". If I turn it up to 2 it will look similar to my sony 17" LED connected to my AGA MK2 via DVI. The letters and everything becomes blocky and pixelated. So I think this low sharpness mode is really nice for the Amiga.

Edit: forgot to mention that with Indy scandoublers Lines will be enabled in PAL gaming. This will make the colours much more faint VS RGB to VGA on the BL 702A. And since the BL 702A has the sharpness settings (1 is nice for Amiga use) the games and everything will look very vibrant and colour full without the graphics being too blocky and pixelated.

[Jope]

Yep, this is how it goes. The a1200's RGB output is a lot "lighter" than the A500s.

They used an off the shelf DAC instead of creating their own video hybrid, as is in the OCS/ECS machines.

[turrican9]

Originally Posted by Jope

Yep, this is how it goes. The a1200's RGB output is a lot "lighter" than the A500s.

They used an off the shelf DAC instead of creating their own video hybrid, as is in the OCS/ECS machines.

Thank you so much for the confirmation. Now I don't need to worry about anything being wrong with my Amiga 1200. So in other words the OCS/ECS Amigas has a better image quality at standard settings, in my opinion. As I said, after increasing gamma and contrast I could get the Amiga 1200 image pretty similar to A500/A600. But still I think the A500/A600 was a little bit sharper and the black was more black VS A1200, on the BenQ BL702A.

[spudje]

Would that eplain why my CD32 has very "light" black via RGB on my TV. Limited TV configuration does not get it black enough IMO.

[turrican9]

Originally Posted by spudje

Would that eplain why my CD32 has very "light" black via RGB on my TV. Limited TV configuration does not get it black enough IMO.

So you have a RGB output mod for the CD32? Anyway, it's very likely since the CD32 is basically a Amiga 1200 without keyboard and floppy.

[spudje]

Yes, the kipper2k one. Guess I'll try once more getting it as black as possible

Hi,

Got myself BL702A for my A1200 and it's really really nice indeed. Picture cleared up when I set the pixel clock to 94 and put phase around 42-44 mark.

Did anyone else notice any vertical lines/ghosting on solid black colours when looking at the monitor from top angles? is this normal? or is it to do with 1200 RGB output not being as good as 500s?

It's not very visible nor any sort of deal breaker but would like to know where the problem is.

Thanks,
Kapuston

[turrican9]

Originally Posted by Kapusta

Hi,

Got myself BL702A for my A1200 and it's really really nice indeed. Picture cleared up when I set the pixel clock to 94 and put phase around 42-44 mark.

Did anyone else notice any vertical lines/ghosting on solid black colours when looking at the monitor from top angles? is this normal? or is it to do with 1200 RGB output not being as good as 500s?

It's not very visible nor any sort of deal breaker but would like to know where the problem is.

Thanks,
Kapuston

Late answer.. But I get these vertical lines on all my Amigas. when using RGB to VGA on the 702A. But I get it aswell on a LCD TV I have, using RGB to scart. They are less visible on my Amiga 500s VS Amiga 600/1200. I can tune phase clock so they don't show, however then the picture will not be as sharp. I think Amiga 500 have a tad better RGB picture VS A600/A1200. In my opinion the Amiga 500 has a better build quality. Amiga 500 also requires a different phase clock VS A600/A1200 on the same screen.

Another interesting thing is this video which shows a review of James Pond from Sega Genesis. You can see the same vertical lines in this video. So I assume this is how RGB works on flatscreens.

[ Show youtube player ]

[Stratosplat]

Originally Posted by turrican9

So I assume this is how RGB works on flatscreens.

Only if the lines are present in the source signal already.

[paul1981]

Overstrained PSU leads to poor video output. Make sure your PSU's are beefy enough.

[robinsonb5]

Originally Posted by turrican9

You can see the same vertical lines in this video. So I assume this is how RGB works on flatscreens.

Yes, it's basically an interference pattern between the number of pixels the flatscreen is expecting to see and the number of pixels that the Amiga or Megadrive is actually displaying.

As the output pixel changes the output signal doesn't jump immediately to the new level and stay there - it will generally slew, overshoot and ripple for a bit, before settling down in time for the next pixel change. When the flatscreen samples the incoming signal, if it samples some pixels during the ripple and some pixels after they're stable, you see the vertical band effect. That's why changing the pixel clock can help - if you're really lucky there's a setting where every pixel is sampled at the same point, and then the bands vanish.

[turrican9]

Well, got myself a BenQ BL 912 today. Happy to say it works just as well as my two BL 702As. Pixel clock on this one had to be at 75 for the picture to clear up perfectly. Also turned sharpness to 1 for that little blurry effect which works well with Amiga games.

[dirkies]

did notice with my IndivisionAGA MK2cr (DVI) that sometimes the BL912 says "out of sync" with HighGFX mode, while it should not be out of sync!
Just turn off and on again the LCD fixes the issue. Do not have that issue with other LCDs.

[wazza]

Hi,

I recently purchased a Benq 702a for use with my Amigas and have started using it with a VGA cable I made myself from an old extension cable I had for the RF modulator on my old A500plus (I chopped off the end and soldered on a D-SUB connector for the monitor).

My experience so far is perfect for games and hi-res screens in workbench but I have not been able to get any of the higher res screens to work in workbench. I have tried using dblpal, euro72, highgfx etc. Some of them just don't work at all and I either get a black screen or a message telling me the mode is out of range. Some work but the image has lines and lots of distortion and no matter what settings I select on the monitor I cannot get a clear picture. Some of the interlaced modes work but there is too much flicker to be able to use them at length.

Does anyone have any suggestions as to how I can find a usable high res screen mode? I have seen different reports from different people on the other threads I have read which has led me to believe I might be doing something wrong and I have not used anything other than the standard WB screen modes in the past as I've always connected my Amigas to TVs.

[dirkies]

I did notice when switching resolutions to high ones with the indivisionAGA (over DVI) that the BenQ would often say "out of sync" but simply switching off and on again the monitor fixes the issue!
I do not have this issue with a "normal" LCD which does not downsync to 15Khz.

[Riempie]

Dirkies: I can confirm this. Also when quitting whdload-games the monitor sometimes has problems with a very high resolution (out of sync error). Switching the monitor off and on fixes this issue. This in combination with my Indivision MK2.

DVI is only available on the Benq BL912-monitor. I did use the vga-output too with a vga-rgb adapater. You can't use the very high resolutions with a vga-rgb adapter because that looks bad or doesn't work well. You need the indivision for that..

[turrican9]

The whole point for me with the BenQ BL 720A/BL 912 is a true RGB picture with smooth 15KHz gaming. Also the fact that you get free anti aliasing with the RGB signal. For example using BL 702A at it's default sharpness level 1 directly on the RGB gives the same kind of anti aliasing a LED screen connected to a AGA MK2 with scanlines at 50%. The 702A on RGB does it without scanlines which looks much cleaner. scanlines will also darken the picture. BL 912 has a higher range of sharpness level and from 1 to 3 will be fine.

I have other LED screens for connecting to my AGA MK2 or Indi ECS scandoublers. I then use hi-res workbench and scanlines for games. On the AGA MK2 I make a custom resolution of 720x576 and use overscan to fill the screen in workbench. This will give the correct aspect ratio. Games will not be full screen (which they should not) and at the same time it will give headroom for those games that use the extra overscan area. Oh, and also when I make custom 720x576 for both hi-res and lo-res PAL (for lo-res you have to divide the 576 by two) the switching between workbench and games will be smooth and no delay. Basically when you connect a BenQ BL 702A or BL912 directly to RGB it will give the 576i resolution anyway. So for me this is the correct PAL resolution. Edit: Indy ECS in 1:1 50Hz mode will also be 576i.

When I use scandoublers I don't try and use any kind of 50Hz mode because AGA MK2 does not have Vsync and Indy ECS has issues with remembering 1:1 mode. As I said for 15KHz/50Hz you cannot beat BenQ BL 702A/BL 912 connected to RGB for smooth and great looking gaming. Important to finetune pixel and phase clocks!

I've found that if you want the best of both worlds on one Amiga you can have two screens. One BL 702A/912 connected to RGB for gaming and one other LCD connected to scandoubler for Hi-res workbench. However, I have so many Amiga configurations that I don't really need to do this.

Anyway, this is just my 2 cents.

[amigasith]

Originally Posted by wazza

...I have not been able to get any of the higher res screens to work in workbench... Some of the interlaced modes work but there is too much flicker to be able to use them at length.

Same here I am really curious if there is any screen mode that I don't know yet that gives a nice and flicker-free high resolution picture on the Benq BL912 / BL702 monitors. Alternatively, I would also use an interlaced mode if anyone knows how to get it flicker-free...