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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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Gerbrand
Joined: 13 May 2008
Posts: 199
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| Posted: Tue Feb 15, 2011 7:33 pm Post subject: |
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| Nashou66 wrote: | What does your gamma curves look like?
Athanasios |
I think it is also OK. Red could be a little better, though.
Gerbrand
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BG1209s (color filtered,new LUGs!), 13000h
Bat cave
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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Gerbrand
Joined: 13 May 2008
Posts: 199
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| Posted: Tue Feb 15, 2011 10:49 pm Post subject: |
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| Nashou66 wrote: | I should have specified, the flat gamma curve/Graph. its easier to see how well it tracks to what gamma you chose.
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I think this is the graph you are looking for. As I said, red needs some more work.
Gerbrand
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BG1209s (color filtered,new LUGs!), 13000h
Bat cave
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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tse
Joined: 03 May 2006
Posts: 1014
Location: Sweatbucket, Fl.
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| Posted: Wed Feb 16, 2011 1:24 am Post subject: |
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| ecrabb wrote: | | Gerbrand wrote: | | I also noticed that there is hardly any difference between full screen and a 1/4 window. I always thought that CRTs were supposed to reduce the intensity for a full screen to protect the tubes from overheating. |
Somebody can correct me if I'm wrong, but it was always my understanding that this had to do with the video amplifier not being able to supply enough current to light up the entire tube face at the same brightness as a smaller window.
If the 1/4 window is no brighter than the full screen, it seems like it could be just as likely the projector causing the problem as the tube. Unless, of course you'd measured it before and this wasn't occurring with the old tube.
SC |
The video amplifier needs to have enough voltage drive (about 120V) to get a peak current of about 3000ua from each tube. The average anode current is limited to about 1000ua (takes about 90V) so that the average screen power does not exceed 34 watts. Tube can implode if driven with higher average power.
A 10 or 20% area white window should be able to be driven with more than the 90V that it takes to get 1000ua current with a full white field. Turn up the drive/sub-contrast or whatever it is called to get the higher peak light output.
Scott
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Gerbrand
Joined: 13 May 2008
Posts: 199
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| Posted: Wed Feb 16, 2011 2:38 pm Post subject: |
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| Nashou66 wrote: | That looks pretty good!!!
Are you using a VP or is this all done in the PJ?
Athanasios |
No VP, just the controls in the Barco. Red and green were almost perfect to start with. The Barco has quite extensive gamma controls for blue (additional slope, possible to lift the mid level IREs, etc.). This was combined with defocusing the blue tube slightly.
First time I tried this...
Gerbrand
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km987654
Joined: 25 Jul 2007
Posts: 2874
Location: Australia
TV/Projector: Barco BG809s
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| Posted: Fri Feb 18, 2011 9:44 am Post subject: |
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| km987654 wrote: | | zGman wrote: | | Never seen Blue/blue - what type of tube? |
Sony 09MEX2 |
It would be good to get information on this. The 09MFX3 tubes are also Blue/Blue.
Last edited by km987654 on Sun Feb 20, 2011 6:40 am; edited 1 time in total
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zGman
Joined: 22 May 2006
Posts: 599
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| Posted: Fri Feb 18, 2011 6:56 pm Post subject: |
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I don't know much about Sony tubes - The 1292 had a reputation for having
very detailed picture quality, but I have never seen one in action.
Others here may have spec sheets, direct experience, etc
G
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