CurtPalme.com Home Theater Forum

Chuck Anstey · Joined: 14 Mar 2010 Posts: 10

I have had my G70 for 10 years and a little over a year ago I got a used Moome IFB-HD v1 card and Lumagen Vision HDP to improve over component inputs and so I could use my HD-DVD or Blu-ray player to play DVDs. I redid all of the setup from scratch and it produces a good picture but having seen other closeup shots of other G70 performance I have some questions. The G70 is ceiling mounted in a 100% light controlled bat cave. I use a resolution of 1920x1080p@48Hz. I am normally very sensitive to flicker up but for some reason this doesn't bother me watching movies and 3/2 judder drives me crazy. I believe I can set up the G70 pretty well and understand what is going on and I am an engineer by training but I don't know what I don't know so I could be only okay at this. I have read everything I can on setting up a G70 but without knowing what is theoretically possible, I don't know if there is still something to be improved because I didn't do a step perfectly.

Questions:
1. Just how well should the G70 resolve the "every other line" 1920x1080p? On mine I can make out the lines for each color but it goes from mid-color to slightly darker mid-color say 55 IRE to 45 IRE (a pure guess). I have seen close up screen shots of other people's G70s and they seem to get a much stronger transition from like 2/3rds bright to 1/3rd bright (i.e. better resolved). Would a V2 card help with the G70? I thought most of those mods were really for 9" CRTs and my lesser 8" didn't get into the bandwidth the V2 improved. I had thought about getting the V2 just for all the resolutions available that are not supported on V1.

2. I have a geometry problem with my blue tube. The blue tube aligns well with R and G except about 2/3rds right of center. At that point it is far to the right of the R and G but then comes back to alignment at ~85% to 100% right. So if I align the outer edge, the middle right side is seriously out of alignment and cannot be pulled in. If I align the middle right as best I can, the last 20% of the right hand side is way outside of the R and G. Am I doing something wrong or do I have a hardware failure? I didn't have this problem in the past in the DVD days when I was running 1440x960 from a HTPC. Right now I compromise the last 50% of the right side to get an overall near alignment.

I have been considering moving to digital because of ease of setup and 3D but I love the smooth, pixel free look of the CRT and now I find out it is possible to do 3D on the CRT. I am trying to find out what is the best I can do with the G70 and how do I get there. I have considered trading in my HDP to get a Radiance XS 3D (XS+ should be pointless on a G70 I thought), upgrading my Spectracal Enhanced Spyder to the new X-right Display 3', and getting either a V2 or ext V3 3D card. The Radiance and Display 3 would be useful in the future even if I went digital at some point but the cost of doing that now isn't that far from some good digital options that out of the box are quite good and I could use the HDP on the digital to help with the primaries. My other concern is that any day I could develop an electronic problem that turns my G70 into a spare parts machine so the less money spent specifically on the G70, the better.

I have done the "reset from scratch and try to improve the image" several times but I think this really should be the last time. It's a Catch-22. If I can improve it then I was watching a sub-optimal picture before that and I should have done better. If I am watching as good as it gets now, then there is nothing left to improve without changing technology. My wife really wants me to downsize to a digital projector so getting a G90 seems an unlikely solution.

derik736 · Joined: 26 Mar 2011 Posts: 28 Location: POland

I guess lot of us have similar point of view depending G70 and other CRTs. As for me, i made a trip to a local Sony dealer to check the sony vpl-hw20 which is about 3000 euro here in Europe. It´s small, easy to set up, full hd etc etc...Anyway i found the picture quality by hd material very OK, i mean i wasn´t speechless as i saw it, it was just OK. Somehow i had the same strange feeling as i would watch a movie on my laptop screen, very "digital" look. My wife felt in love in this pj, due to it´s size of course.
After that we watch some material in SD and than it just sucked. I mean it was so bad as we would watch vhs material. Nothing to compare with crt. And since we still have a lot od DVD it´s a major point by our projector choice.
Here at home, connected to htcp, my G70 is still reference, at least for me and my wife. Very smooth, natural, spectacular picture with great tones. And for the price of HW20 i can buy two G70 with new tubes for another 20 years of use.
Give your G70 a chance, it still have a lot of potential, even if modern pjs have more resolution and smaller size, crt still benefits from better overall picture quality.
Just my two cents..

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

Well, I can't really answer #2. My guess is that there is something wrong with a board.

As for #1, I can't comment on the different versions of Moome's cards. I wouldn't believe that it would make that big of a difference in your set up. On your pj, what cr and br are you running? If you run the cr to high, then it can reduce the sharpness. I doubt the screenshots are representative to what is actually going on. You might want to test your bandwidth by throwing up tse's test image and see how that looks. At the end of the day, a CRT is never going to be as sharp as a digital.

I like your upgrade path with the VP, meter and card. The newer card might be the last thing you want to purchase, since that would be the only thing you would need to sell if you go digital. Sticking with CRT allows you more time to wait to see how digital progresses. LED and Laser are coming along and should be affordable in the next couple of years. Epson will be shaking up the LCOS world with their new chips at cheaper prices. By 2015, 4k should be here in the under $10k price range.

Chuck Anstey · Joined: 14 Mar 2010 Posts: 10

I realize the G70 will never be as sharp as a pixel perfect 1080p digital but I don't think I am getting as good as other G70's. I also understand Derik's feel of looking at something digital. I seem to be blessed with very good eyesight for high contrast thing like screen door that I can either see directly or clearly detect at any distance that would be normal viewing distance from a projector. I have been patiently waiting for digital to improve for 10 years since I bought the G70, replacing my old Sony VPL-400W, the original 16x9 LCD projector. I'm not married to CRT but I do want to figure out just how good I can make it.

One thing I have noticed is that using the MG Focus pattern of 9 dots for the Green tube, no matter what I do, the dot has a little faint flare coming up from the top center, making it look like a little flame. Shifting the center as high as it goes does not change this flare one little bit nor does AQP/DQP and seems immune to any focus adjustments. I can purposely make the dot horizontally oval and it is still there. It is less visible than the normal small halo surrounding the focused dot.

betel · Posted: Sat Aug 13, 2011 4:34 pm Post subject:

"2. I have a geometry problem with my blue tube. The blue tube aligns well with R and G except about 2/3rds right of center. At that point it is far to the right of the R and G but then comes back to alignment at ~85% to 100% right. So if I align the outer edge, the middle right side is seriously out of alignment and cannot be pulled in. If I align the middle right as best I can, the last 20% of the right hand side is way outside of the R and G. Am I doing something wrong or do I have a hardware failure? I didn't have this problem in the past in the DVD days when I was running 1440x960 from a HTPC. Right now I compromise the last 50% of the right side to get an overall near alignment. "

When I ran a G70, the only geometry problems I had were at the perimeter. Probably because I used as much of the tube face as possible.

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

I understand what you are saying Chuck, but think you are probably thinking that others may look much better than yours. I think you would be surprised when you see a lot of these in person.

As for digital, I have been watching along with everyone else. At this point, I would say if your G70 puked today then toss it and grab whatever new JVC, Sony, or Epson comes out at Cedia. They look great, but still lack the motion res and on/off cr of CRTs. If you want everything but on/off then grab a VDC LED dlp. With black frame insertion, it has the motion res of CRT.

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

pics

Chuck Anstey · Joined: 14 Mar 2010 Posts: 10

My flare is nothing like your bad flare and my defocused flare looks just like your good flare. It is when it is focused tightly that the faint little tiny flame top shows up and the softening would be in the vertical resolution but it is far less visible than the halos in your images and much much smaller.

The ghosting is not from this but an optical issue with me. I took a 1/60s picture of the screen so I would have only one frame and there is no double image of the stars. I believe the double star is caused by my not tracking such a large jump at only 24fps so my brain doesn't see the second star as the first one moved but rather two distinct stars. If I try really hard to track then I can make it mostly disappear but it takes a very conscious effort due to the low frame rate. So motion blur on an LCD where there really is a ghost image looks somewhat normal to me. I just assumed everyone sees the same thing I do.

At 817p at 48Hz, I can resolve every other HLine and VLine, although obviously not a full black/white transition so I think I have it set up mechanically and EM focused pretty well but it would be awesome if it could get even better. I have asked in the Moome products forum if an IFB-HD v2 card is a visual improvement of the v1 card for a G70. I seem to be bandwidth limited as 1080p at 48Hz cannot resolve every other HLine although that is ~126MHz, slightly beyond the 120MHz limit of the G70 so the v1 card may not be a bandwidth limiting factor.

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

Chuck Anstey · Joined: 14 Mar 2010 Posts: 10

The V1 card does not support 72Hz or at least I cannot get the VisionHDP to send 72Hz. It just reverts to 60Hz when I try so I had assumed it was the V1 card rejecting the 72p or even 96i. I thought a secondary advantage of the V2 card would be all the modes it supported over the V1 card.

The double image isn't the low refresh rate but the low source frame rate. I have pictures that show there is no double image produced by the CRT and the image would change at 24Hz anyway, not 48Hz or 72Hz (i.e. no motion flow) so other than flicker, there is no difference between refresh rates. Whether a frame is drawn once or 20 times in 1/24th of a second, it is still on the screen for 1/24th of a second and then it changes to the next frame. I am confident the double image is that I still "see" in my mind's eye the old frame and the new frame instead of one tracked frame because the jump is too large. With a higher source frame rate I wouldn't have this issue as much. I have read some reviews of digital projectors that make me think this is a somewhat common problem. There have been reviews of digital projectors that say there is still bad motion blur of "Projector X" but someone did high-speed analysis of the image showing there was none so it was the reviewer seeing something that wasn't there. So if it's there I'll see it and if it isn't there I'll still "see" it so digital projectors look the same to me at least at 24p.