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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Sun Aug 31, 2014 10:05 am Post subject: |
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| stridsvognen wrote: | | I also understood you pointed out they had 7 peakings onboard, that indicates there must be a bandwidth problem, as the old modified boards have 0 peaking addet |
To judge this, you'd have to know what really peaking is.
To illustrate this I circled all the "peaking" components on the old VNB. I am really curious if all those peakings are removed from your "zero peaking" VNB.
If you really that concerned about peaking methods you really should read this: National AN1013, page 16, section 7 - Peaking methods. It wasn't written by Mike Parker himself, yet it has probably based on a true story... Of course all the industry leaders did these methods, and this many company shouldn't get wrong right.
_________________
projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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stridsvognen
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| Posted: Sun Aug 31, 2014 10:44 am Post subject: |
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| gjaky wrote: | | stridsvognen wrote: | | I also understood you pointed out they had 7 peakings onboard, that indicates there must be a bandwidth problem, as the old modified boards have 0 peaking addet |
To judge this, you'd have to know what really peaking is.
To illustrate this I circled all the "peaking" components on the old VNB. I am really curious if all those peakings are removed from your "zero peaking" VNB.
If you really that concerned about peaking methods you really should read this: National AN1013, page 16, section 7 - Peaking methods. It wasn't written by Mike Parker himself, yet it has probably based on a true story... Of course all the industry leaders did these methods, and this many company shouldn't get wrong right. |
I cant say how much was removed on the old boards, but there is a lot of components missing.
Im also aware that peeking is needed in some amount in a analog chain like this, but ill say less peaking and more real bandwidth clearly looks better.
And my experience say its ok to peak a bit as long it never do a overshoot on the 1:1 horizontal line at 100% IRE output.
If the bandwidth is so poor that it needs heavy peaking to get the vertical line right, and it then overshoot on the horizontal line, ill prefer some roleoff on the vertical.
I also seen the spec sheet on the AD834 used on the 03VIM, and its describes built in peaking with 0 overshoot.
The old standard Marquee VNB have peaking, and its visible that it do overshoot, and its important to remove that when a high bandwidth VIM is addet.
I also think that the low noise level on the MP mods free up a lot of bandwidth, so its hard to say what do what.
I asked others to shoot some pics of the 1:1 pattern starting with contrast at 0 and slowly turn it up, and display how the pattern behave.
If you can display a perfect horizontal line with no overshoot, and get the vertical perfect out of black ( Use the horizontal as reference) You have sufficiant bandwidth, and perfect matched peaking for the selected resolution.
And what makes the Marquee the best CRT projector ever is its high standard bandwidth, and its potential to be optimized for HD material.
Last edited by stridsvognen on Sun Aug 31, 2014 11:09 am; edited 1 time in total
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Sun Aug 31, 2014 11:08 am Post subject: |
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One question about the focus of the Marquee. The focus coil of the Marquee can be replaced with a 909 focus coil I understand. Is that easy? I remember that there was a Franken yoke or something? With my 8500 I had very early blooming when I put contrast higher.
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stridsvognen
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| Posted: Sun Aug 31, 2014 11:23 am Post subject: |
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| redfox001 wrote: | | One question about the focus of the Marquee. The focus coil of the Marquee can be replaced with a 909 focus coil I understand. Is that easy? I remember that there was a Franken yoke or something? With my 8500 I had very early blooming when I put contrast higher. |
I run standard yokes with the MP mods, and dont have blooming.
What you will see with these mods is that when removing noise in the video chain you will get less blooming, but also less max light output.
A standard Marquee wont pass a contrast above 70 without quite some blooming.
Whats interesting is the max light output with 0 blooming, the contrast nr dont matter.
Lets say i can run 12fl at 100 contrast with 0 blooming, but on a standard ill have blooming from 6fl and up, and a lot of blooming passing 10fl. who might be at 70 contrast.
So the first thing you want is to get the noise out of your video chain, get the bandwidth performance, and then you might like to play with yokes lenses and tubes.
Looking into my LCP tubes from a distance, i see scanlines on the tube faces, and thats with standard yokes. I cant say how it will look with 909 yokes, that you need to ask Mike about, think he uses 909 yokes.
I think i reached a new level of performance last night, and thats has most to do with the video chain before the analog input in the Marquee.
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Sun Aug 31, 2014 11:43 am Post subject: |
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Strids, I'm surprised to see that you haven't tried the HTPC way, with analog RGB out yet.
_________________
projectors in the past : NEC 6-9PG xtra, Electrohome Marquee 6-7500, NEC XG 1351 LC ( with super modified Electrohome VNB neckboard !!!)
current: VDC Marquee 9500LC
The MOD: VNB-DB, VIM-DB
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Sun Aug 31, 2014 11:45 am Post subject: |
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Ok I am reading this thread now and it seems I could use the complete barco electronics on the tubes as MP seems to do that.
http://www.curtpalme.com/forum/viewtopic.php?p=247327
I have a 809 tube housing with all the electronics but the focus coil is cine 8 or 1209. I think the Marquee is the same both don't have the 6 pole astig?
If so I am thinking about using the Barco split pack tube housing. Lengthening the cable from a Marquee unit. That way the fan noise is gone too.
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stridsvognen
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| Posted: Sun Aug 31, 2014 11:51 am Post subject: |
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| gjaky wrote: | | Strids, I'm surprised to see that you haven't tried the HTPC way, with analog RGB out yet. |
With the amount of stuff i have here to test, i doubt it will happen anytime soon.
And on top of that i have never seen anyone post anything from a HTPC that made me want to try it.
That might not be the mistake of the HTPC, but i guess its also a jungle out there to find the right video cards and stuff.
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Sun Aug 31, 2014 11:55 am Post subject: |
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| stridsvognen wrote: | | gjaky wrote: | | Strids, I'm surprised to see that you haven't tried the HTPC way, with analog RGB out yet. |
With the amount of stuff i have here to test, i doubt it will happen anytime soon.
And on top of that i have never seen anyone post anything from a HTPC that made me want to try it.
That might not be the mistake of the HTPC, but i guess its also a jungle out there to find the right video cards and stuff. |
Exactly. I tried a lot with the HTPC and it never ran smooth so one day I gave up. Than I had a Mac and discovered that as long as you stay within the bitrates of 12GB for a 1080p movie I had the best performance ever. I also had a Lumagen HDP scaler ones but the Mac looked better (or the same). The Mac is not a high power video solution but what it is capable of it does extremely well. Much better than any media player I tried with the exception of the Xtreamer first model.
Have to add that I don't do any gamma correction with it but a little is possible. I have a profile with resetted video card gamma table. Doing to much gamma correction gives color banding as the cards are 8 bit. The scaling from 1080p to 720p looked good but perhaps I don't know what to look for.
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stridsvognen
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| Posted: Sun Aug 31, 2014 2:37 pm Post subject: |
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| redfox001 wrote: | | stridsvognen wrote: | | gjaky wrote: | | Strids, I'm surprised to see that you haven't tried the HTPC way, with analog RGB out yet. |
With the amount of stuff i have here to test, i doubt it will happen anytime soon.
And on top of that i have never seen anyone post anything from a HTPC that made me want to try it.
That might not be the mistake of the HTPC, but i guess its also a jungle out there to find the right video cards and stuff. |
Exactly. I tried a lot with the HTPC and it never ran smooth so one day I gave up. Than I had a Mac and discovered that as long as you stay within the bitrates of 12GB for a 1080p movie I had the best performance ever. I also had a Lumagen HDP scaler ones but the Mac looked better (or the same). The Mac is not a high power video solution but what it is capable of it does extremely well. Much better than any media player I tried with the exception of the Xtreamer first model.
Have to add that I don't do any gamma correction with it but a little is possible. I have a profile with resetted video card gamma table. Doing to much gamma correction gives color banding as the cards are 8 bit. The scaling from 1080p to 720p looked good but perhaps I don't know what to look for. |
My goal is to have a smooooth video chain who dont change anything in the digital domain, exept the 4:2:0 to 4:2:2 convertion that we cant avoid. And then converts to RGB for the DAC.
All the experiments i have ever done shows that processors always degrade the image somehow.
So if you want the ultimate PQ stay out of digital manipulation, use as few processors in the video chain as possible, and only the best blu ray player. Get the best calibration possible out of the CRT options.
To point out how much digital manipulation in the Radiance messes up the image, i had a friend over to look at the G90 and he pointed out some issues, i was thinking a bit and turned off the CMS in the radiance, and he right away asked.. What did you do. Just activating the CMS and change 1 adjustment 1 point.
And thats how clear it was even on a CRT who have a ton of noise and limited bandwidth with quite some peaking distortion.
After that experience i went back to play 1080P 60hz direct from player to the Moome card, WOW that looked good, from there i have been experimenting to get back to 1080P 72hz, finding the processor capable of that without messing the signal totaly up.
Look at the croma signal direct from a player, and then true a processor, and you will see very clearly that it messes up more than you think.
It do all kind of funny stuff limiting the 2x2 color resolution, and lower resolutions, looking the big vertical bars ( ultra low resolution) you will se how processors soften or add ringing to the croma signal, depending if you change colorspace and so on.
At the moment the radiance also messes up the gray ramp/ bit dept, making all kinds of funny steps.
So first thing i look for today when running another processor in the chain is if it can pass a perfect gray ramp/ bitdept.
How much it add distortion to the croma signal and role off the signal. And then i have a lot of movie scenes to run true, see if i get that warm relaxed feeling, or something bothers me. 
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Sun Aug 31, 2014 6:09 pm Post subject: |
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Ok when I come back to the main question I think the question is if the better digital focus and astig of a Barco 909 will give a better picture when combined with the limited bandwidth.
It seems to me that if the focus of the Marquee is good enough to show scanlines at 1080p it might still jitter a little? I mean I have an analogue frequency generator and a digital and the digital produces much more stable waveforms. I guess my question is if this is true in all cases that an analogue wavevorm generator is less stable? I don't know enough about electronics to know that for sure.
As things look now I might have found Marquee parts and studying my 809 I am reasonable sure I can simple use the cable of the 809 and have the sheimpflug, lug and hfq's etc to try with a Marquee backend. I will miss the 6 pole dynamic astig but in my present setup I don't even use that too.
I think I can place the marquee splitter in the 809 head but perhaps use the barco splitter too without the return cable. The cable between neckboard and vim will be longer than usual so perhaps that will take an extra opamp but probable not.
Last edited by redfox001 on Sun Aug 31, 2014 6:26 pm; edited 1 time in total
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stridsvognen
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| Posted: Sun Aug 31, 2014 6:26 pm Post subject: |
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| redfox001 wrote: | Ok when I come back to the main question I think the question is if the better digital focus and astig of a Barco 909 will give a better picture when combined with the limited bandwidth.
It seems to me that if the focus of the Marquee is good enough to show scanlines at 1080p it might still jitter a little? I mean I have an analogue frequency generator and a digital and the digital produces much more stable waveforms. I guess my question is if this is true in all cases that an analogue wavevorm generator is less stable? I don't know enough about electronics to know that for sure.
As things look now I might have found Marquee parts and studying my 809 I am reasonable sure I can simple use the cable of the 809 and have the sheimpflug, lug and hfq's etc to try with a Marquee backend. I will miss the 6 pole dynamic astig but in my present setup I don't even use that too. |
I think there must be some compromises made running a split pack with long cable run.
I dont want to be negative here, it would truly be a fun project, but why bother with all these troubles not knowing if it will be a big wast of time.
Find a Marquee 9520 split pack, move the tubes, lenses and yokes if you like, go for a known working solution.
There was 5 sets of Marquee 9520LC on ebay some time back, who is born with LUG tubes, i bought some of the new LUG tubes he had for 200$ pr tube, complete tubes with housing and magnets.
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Sun Aug 31, 2014 6:29 pm Post subject: |
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| stridsvognen wrote: |
I think there must be some compromises made running a split pack with long cable run.
I dont want to be negative here, it would truly be a fun project, but why bother with all these troubles not knowing if it will be a big wast of time.
Find a Marquee 9520 split pack, move the tubes, lenses and yokes if you like, go for a known working solution.
There was 5 sets of Marquee 9520LC on ebay some time back, who is born with LUG tubes, i bought some of the new LUG tubes he had for 200$ pr tube, complete tubes with housing and magnets. |
The cable might be a problem but I will start with a short one 
I am searching for a 9520 split pack and I did bid on that set on ebay but still it was 2500$ plus shipping. What I have in mind now will cost me very little at first. The money will be spend on the MP mods.
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Sun Aug 31, 2014 6:41 pm Post subject: |
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And now I will enjoy my Cine Max again because the differences will be very very small just fun to see where we can get and what we can learn.
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stridsvognen
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| Posted: Sun Aug 31, 2014 6:44 pm Post subject: |
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| redfox001 wrote: | | stridsvognen wrote: |
I think there must be some compromises made running a split pack with long cable run.
I dont want to be negative here, it would truly be a fun project, but why bother with all these troubles not knowing if it will be a big wast of time.
Find a Marquee 9520 split pack, move the tubes, lenses and yokes if you like, go for a known working solution.
There was 5 sets of Marquee 9520LC on ebay some time back, who is born with LUG tubes, i bought some of the new LUG tubes he had for 200$ pr tube, complete tubes with housing and magnets. |
The cable might be a problem but I will start with a short one
I am searching for a 9520 split pack and I did bid on that set on ebay but still it was 2500$ plus shipping. What I have in mind now will cost me very little at first. The money will be spend on the MP mods. |
Ill recommend you to buy a cheep 9500LC ultra, complete machine with nice tubes, get the mods up running, and get a good feeling about the Marquee before you start inventing the deep plate and the hot water.
And as i wrote before there is a hole lot of work just finding the digital video chain and DAC part who will do a signal who is worthy of a well moddet Marquee.
So when you have a Marquee setup running a perfect 200Mhz 1080P 72hz signal, where you will be able to see pixel resolution looking at the tube face, and totaly noise free low level, and you still want more, its might worth to play with the LUG tubes and 909 yokes.
I also want to do 16:9 masking on the tubes to improve contrast, before i move to the tube/ yoke project.
Im curious when is a CRT tube to sharp, the scanlies have to much gap? Light up less tube face, needing more gain to produce the same light on screen burning the tubes faster.?
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stridsvognen
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| Posted: Sun Aug 31, 2014 7:02 pm Post subject: |
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| redfox001 wrote: | | And now I will enjoy my Cine Max again because the differences will be very very small just fun to see where we can get and what we can learn. |
You might change that statement once you seen what low noise and real high bandwidth do to a CRT image together with a reference source.
It takes some to keep up with a good digital projector, i cant comment about the 909, but your shots and others indicates its no better than the G90, and i can easy say ill prefer my JVC X7 over my G90.
What the Marquee do has not so much to do with sharpness, its the way it displays a organic/ realistic image like nothing else, not even any other CRT i have seen do that. And working on that quality brings out something unike, and you wont care so much about sharper tubes lenses yokes and stuff, as you will notice that there is other parameters who matters more to the total experience of a movie.
I feel the lens tube, the hole sharpness debate is leftovers from a time where that was the only parameters to tweak on.
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Sun Aug 31, 2014 7:28 pm Post subject: |
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Ok a good point but I know what it does on 720p it almost perfectly resolves. I do see something I like and I am very grateful for the discussion because I see my Barco is doing much better now yesterday on 804p. When I just add up everything I am pretty sure that the improvement will not be huge just a little. Perhaps a jittering focus dot will cost some sharpness too? I don't know for sure but the Barco is terrible sharp and noise free.
However I did use some trics learned in audio to make even a longer video chain perform organic and the result is like looking through a window or even better like the space of the movie is in you own space. That was the organic part I was looking for and I found some people that knew much more about it.
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stridsvognen
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| Posted: Sun Aug 31, 2014 8:55 pm Post subject: |
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| redfox001 wrote: | Ok a good point but I know what it does on 720p it almost perfectly resolves. I do see something I like and I am very grateful for the discussion because I see my Barco is doing much better now yesterday on 804p. When I just add up everything I am pretty sure that the improvement will not be huge just a little. Perhaps a jittering focus dot will cost some sharpness too? I don't know for sure but the Barco is terrible sharp and noise free.
However I did use some trics learned in audio to make even a longer video chain perform organic and the result is like looking through a window or even better like the space of the movie is in you own space. That was the organic part I was looking for and I found some people that knew much more about it. |
Try post some pictures of your 1:1 with low contrast VS full contrast. Look into the tubes and tell me how it comes out of black, and translate that to the low level deatil level on movie material.
And can you display a 5% ire window where its total black around the window, and no noise to detect anywhere looking into the lens.?
And last, whats your source.? How is your croma signal passed, and do you have perfect bitdept/ grayscale.
When you look into the lens displaying a gray ramp you will be able to see if it graduate even, or uneve, it should have small steps all the way with no difference in step wide, and no overlap/dark lines betwen or other distortions.
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stridsvognen
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| Posted: Sun Aug 31, 2014 9:03 pm Post subject: |
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Free hand bad optical focus and convergence, and a bad angle on screen, im hopless at taking screen shots.
But i might think its possible to get a idea of the fine detail level, even with optical messed up focus, and camera banding.
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Mon Sep 01, 2014 2:17 am Post subject: |
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Ok will look into it. I tried lowering contrast and on 720p one on one became a lttle better possable on low contrast not much to notice 804p nothing to notice but did not look in tube. I also see perfect bladk on the screen when I see the end title of a movie. What i was wondering on and what I do not understand is that I see a mirror reflection of the white words. If the word is far enough from the center. I mean whe the line is at the bottom I see a weak white mirror reflection on the top. I checked if by any chance the coating of the lens is damaged but the coating is near perfect except very little scratches. The anti reflecting coating is there but still the mirroring. I never had liquid coupled bedore so perhaps this is normal? It is not a halo around an object that makes contrast worse. Well it almost keeps me out of my sleep. As I said perhaps it is normal for the curved lens to reflect to the oposite of the screen a little with liquid coupled lenses? The reflection is also perfect white so if it was bad coating than all three are exactly the same bad so I don't think that.
I do not recognise what I see on the screenshot but I will look on a normal screen tomorrow. But it looks sharp whatever it is!
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Mon Sep 01, 2014 2:48 am Post subject: |
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One reason why I like Marquee to is because I like to mod and what I see from my Cine max is that one should not f*ck with a max. The reason might very well be that the max is not cooled very much to keep it silent. Every now and than problems apear that seem temperature related. I think that having a split case will keep the electronica cooled better. The way the max is now you have to watch movies and sort of pray  I do not dare to split the max like I originally planned to. I would like to have a Marquee and not to worrie if a part blows
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