CurtPalme.com Home Theater Forum

[stridsvognen]

I need some help here.

Can someone put up a fine grid pattern, like the first one in the Radiance, turn the contrast all the way down, look into the tubes, and tell me what you see first when putting the contrast up slowly.

I just did this on both my standard marquee and my standard G90.. And there is a huge difference in how it behaves.

[CIR Engineering]

On the newest Moome card remove U68 to defeat the gamma circuit. You absolutely do not need Moome gamma correction on a G90 because the G90 runs a 2.2 gamma with the stock gamma settings. You can also adjust the gamma by entering "expert mode" and pressing the "bias" and "gain" buttons at the same time on the remote.

There is peaking on the G90 neck cards using two surface mount caps near the video amps. There is also a peaking circuit on the BA board (= VIM for Marquee).

The G90 internal test patterns are useless for convergence as you have discovered. You are correct to use the Lumagen.

My pattern generator has the overscan patterns that I suggest. You can make your own in Paintshop or any image editing software. Just make a BMP image that is 1080x1920 and draw some borderlines.

craigr

[stridsvognen]

Craig, can you post a closeup of your 1:1 pattern running 817P 72 hz so i know how it can look like.

[CIR Engineering]

[stridsvognen]

Just wonder why my old moome card looks to match quite well at 817P 72hz, it must match the peaking in the G90 video chain. And my new card dont.

[stridsvognen]

Craig i found a old shot of your G90 from 2010 running 1080P 60hz. Dont pick on my convergence and sharpness..

https://www.curtpalme.com/forum_archived/viewtopic.php@t=23601.html

[gjaky]

Kurt, you might like this too:
http://www.avsforum.com/t/959357/g90-mod-attn-chuchuf-craigr-mike-parker-scott-phil-etc
http://www.avsforum.com/t/696950/g90-running-1080p-72hz

[stridsvognen]

[thewolfman]

Sell some pj:s for a Barco 909 instead and you could make the perfect shot out between 3 brands. 3 Marquee's? Really?

[CIR Engineering]

[stridsvognen]

Here is the Moome card who do the nice 817P 72hz.

I removed the add on gamma board, and soldered jumpers instead.

817P 72hz is the only resolution i can make it look like it do on the shots, the peaking G90 peaking is teasing on the other resolutions, so that its have quite a lot of color shift in the vertical lines depending contrast setting.

[stridsvognen]

[gjaky]

[stridsvognen]

[gjaky]

[stridsvognen]

I hear you, but the experience seems quite different, i have never seen any peaking not effected of the output level.

It just seems like there is no substitude to real bandwidth, peaking wont replace that ever in my opinion.

That a bit of peaking is good, or improves the image i agree, but when you have lets say 100Mhz bandwidth, and try to pump it up to respond to a 150Mhz signal, it just makes a lot of mess all the way from Black to White and depending the resolution.

So it wont hold the same color or performance as soon as resolution or light is changed in any parts of the image.

Im not refering to different input resolutions, but different resolutions in the image itself.

[gjaky]

It's all matter of the proper tuning... This is what is properly done on your marquee.

What is real bandwidth? For the high frequency limit the rise and fall times give a good estimation, but that does not mean that the frequency response is flat to it (this is what you want for accurate 'in-scene-low-resolution') this could even mean that more (or broader) peaking is needed to add the missing freqs. to the response!

Without peaking, you wouldn't be able to reach smooth transitions no matter what components you use, as already said the main purpose of the peaking is to cancel the unwanted parasitic effects, without any peaking the parasitic effects would overwhelm all efforts which was taken in the design process, to much peaking of course can fool the response too. The key is to apply just the right ammount of peaking -which is a hard task.

[gjaky]

[stridsvognen]

[gjaky]