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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Mon Feb 15, 2016 2:52 pm Post subject: |
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Redfox, can you not just post the facts, such as the bandwidth of a chip, and ask how Mike got more improvements instead of a bunch of posts that are antagonistic? I'm sure Mike doesn't want to post his exact mods, as that's how he makes money, but as I said before, feel free to challenge, but don't be rude about it.
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Mon Feb 15, 2016 4:16 pm Post subject: |
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| Curt Palme wrote: | | Redfox, can you not just post the facts, such as the bandwidth of a chip, and ask how Mike got more improvements instead of a bunch of posts that are antagonistic? I'm sure Mike doesn't want to post his exact mods, as that's how he makes money, but as I said before, feel free to challenge, but don't be rude about it. |
Well this was my contribution:
Or in English. He passes the first autoclamp that can be disabled in the menu's too. But one high bandwidth part less. The old miniboard is only a switch nothing to improve there. The bigest improvement would come from using a ad834 like Gjaky does but he does not do that. The neckboards well I mentioned them. The blacklevel is clamped on the neckboards. The whole story about black from the moome is nonsence the black comes from the brightness controll and not from the video source. It is clamped at the neckboard in each and evry mod or board.
You must be able to see that he made it go on and on too?
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Mon Feb 15, 2016 4:35 pm Post subject: |
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| redfox001 wrote: | | mp20748 wrote: |
Now this all happened before I was able to get the chip (AD835) to perform up to 300mhz flawlessly (this one you know nothing about).
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From the datasheet:
The AD835 is the first monolithic 250 MHz, four-quadrant voltage output multiplier. This means -3db at 250 MHz. Did you mean Mega Pixel perhaps?
http://www.analog.com/media/en/technical-documentation/data-sheets/AD835.pdf |
Tjeerd, Mike already stated he uses the 'bandwidth' term for the number displayed on his test pattern generator, don't confuse that with the (-3dB) 250MHz bandwidth of the AD835's datasheet.
_________________
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: Mon Feb 15, 2016 4:44 pm Post subject: |
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| gjaky wrote: | | redfox001 wrote: | | mp20748 wrote: |
Now this all happened before I was able to get the chip (AD835) to perform up to 300mhz flawlessly (this one you know nothing about).
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From the datasheet:
The AD835 is the first monolithic 250 MHz, four-quadrant voltage output multiplier. This means -3db at 250 MHz. Did you mean Mega Pixel perhaps?
http://www.analog.com/media/en/technical-documentation/data-sheets/AD835.pdf |
Tjeerd, Mike already stated he uses the 'bandwidth' term for the number displayed on his test pattern generator, don't confuse that with the (-3dB) 250MHz bandwidth of the AD835's datasheet. |
Yes got it. Would he really have improved on the bandwidth of the ad835?
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Mon Feb 15, 2016 4:45 pm Post subject: |
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| redfox001 wrote: | | Curt Palme wrote: | | Redfox, can you not just post the facts, such as the bandwidth of a chip, and ask how Mike got more improvements instead of a bunch of posts that are antagonistic? I'm sure Mike doesn't want to post his exact mods, as that's how he makes money, but as I said before, feel free to challenge, but don't be rude about it. |
Well this was my contribution:
Or in English. He passes the first autoclamp that can be disabled in the menu's too. But one high bandwidth part less. The old miniboard is only a switch nothing to improve there. The bigest improvement would come from using a ad834 like Gjaky does but he does not do that. The neckboards well I mentioned them. The blacklevel is clamped on the neckboards. The whole story about black from the moome is nonsence the black comes from the brightness controll and not from the video source. It is clamped at the neckboard in each and evry mod or board.
You must be able to see that he made it go on and on too? |
Everything you said and or indicated here is false...absolutely false.
Why do you think it's Ok to assume a truth, when there is NO factual support for anything you said it. It is all false, and not only false, it does not apply to anything I'm doing or have done.
To make informed technical statements, you need to first understand what the technical points are.
Ok, let me answer each of these to help you in the future.
- You cannot disable the clamping on the first stage input. Marquee auto clamp deals with the "composite signal" only, and that's an ooption board we don't use.
- The old mini board IS NOT a switch.
- And the idea of using an AD834 instead of the AD835 is just the idea of those wanting higher bandwidth. But anyone with any real experience with either of these chips would go only with the AD834 for higher bandwidth, but if the AD835 can be made to achieve the exact same thing with and even lower noise floor, why go the complex and needless route of the AD834 and etra components when the AD835 can be made to get very similar results with a better noise floor.
- The neck boards yeah, you mean the ones you praise in that link... the ones that you reported to me that had gain issue and later you said one was lacking in bandwidth. Well, you posted a very similar SMPTE of the later VDC boards, not knowing that they pass SMPTE very well at 1080P. Plus, onm the neck boards, one was very old and you had already acknowledged that. But... with the warnings I gave you to NOT work on the boards because I would take care of that, you instead did your thing and informed me of it (according to the emails), you even mentioned how you had messed them up. But then you did apologize for doing that, and that of course is when things got bad between us. truth be told
- The BLACK LEVEL IS NOT CLAMPED on the neck boards.. 
- The Black reference on your 02 VIM comes from the first stage pedestal circuit... the black reference from my latest work comes from the Moome's DAC.
- Black comes from Brightness.. Black may be adjusted and made visible using the brightness control, but if the reference is not present in the source, you cannot get true black from if the reference does not exist.
- Again, what do you mean by black being clamped at the neck boards - WHERE?
Last edited by mp20748 on Mon Feb 15, 2016 4:49 pm; edited 1 time in total
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Mon Feb 15, 2016 4:47 pm Post subject: |
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The old miniboard is not a switch? I will gladly share the partnumber if you want me to?
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Mon Feb 15, 2016 4:54 pm Post subject: |
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| redfox001 wrote: | | The old miniboard is not a switch? I will gladly share the partnumber if you want me to? |
Its proper term is MUX. There is more to it than just a switch, that is its purpose. But because it also has other circuitry in it. It's not really fair to call it a switch only.
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Mon Feb 15, 2016 4:58 pm Post subject: |
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About the clamp int-clamp in the schematic of the vim02 comes from the controller and to my understanding it is set by the menu's. It certainly disables the clamping to 0 V of the black that you do so complicated about.
And yes the clamping is done on the neckboards to with the sample and brightness.
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Mon Feb 15, 2016 5:04 pm Post subject: |
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| redfox001 wrote: | About the clamp int-clamp in the schematic of the vim02 comes from the controller and to my understanding it is set by the menu's. It certainly disables the clamping to 0 V of the black that you do so complicated about.
And yes the clamping is done on the neckboards to with the sample and brightness. |
That sample on the neck boards is not the same sample as in sample and hold that relates to a clamping circuit. In fact, the later VDC neck boards do not have it at all... so how are the clamping the signal on the newer neck boards?
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Mon Feb 15, 2016 5:10 pm Post subject: |
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Oh I forgot.. the brightness adjustment is electronically achieved by varying a voltage on the base of Q12.
| Quote: | | About the clamp int-clamp in the schematic of the vim02 comes from the controller and to my understanding it is set by the menu's |
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cmjohnson
Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s
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| Posted: Mon Feb 15, 2016 7:23 pm Post subject: |
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Going back to my comments on making MTF measurements, the IDEAL way to make them would be right at the CRT face, thus bypassing the effects of the optics and mechanical setup and screen relationship.
However, presuming we're talking about 9" machines we're talking about LC optics and I am NOT certain that you could get a good MTF measurement setup working thru the C element. But then again, I'm not sure that you couldn't, either, as you can see the CRT face and the displayed image just fine when looking at it with the lens body removed. So I tend to think that an MTF reading COULD be made in that configuration. Just acquire any low cost analog video recorder with a video output and a high magnification zoom lens, and you can get those for under 50 dollars in any pawn shop.
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Mon Feb 15, 2016 7:30 pm Post subject: |
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| cmjohnson wrote: | Going back to my comments on making MTF measurements, the IDEAL way to make them would be right at the CRT face, thus bypassing the effects of the optics and mechanical setup and screen relationship.
However, presuming we're talking about 9" machines we're talking about LC optics and I am NOT certain that you could get a good MTF measurement setup working thru the C element. But then again, I'm not sure that you couldn't, either, as you can see the CRT face and the displayed image just fine when looking at it with the lens body removed. So I tend to think that an MTF reading COULD be made in that configuration. Just acquire any low cost analog video recorder with a video output and a high magnification zoom lens, and you can get those for under 50 dollars in any pawn shop. |
Still spot size (LCP vs. LUG), EM focus setting, astig plays a role -unfortunately. IMHO MTF is a good thing but only after everything is done. Also when you want to examine the output directly on the tube face you most likely will decrease contrast with that you get a bandwidth that is unrealistic (think about slew rate).
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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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cmjohnson
Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s
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| Posted: Mon Feb 15, 2016 10:25 pm Post subject: |
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I observe that you are resistant to the idea of using MTF measurements. But MTF measurements, properly made according to established industry procedures, are the only truly objective measurement of contrast vs resolution values.
Yes, of course, there would be some setup aspects to be concerned with. Magnetic setup, focus, astig, geometry, yes, of course, but since when is that new? The industry standard for direct view CRT performance has always included direct to face MTF measurements, and on every single CRT ever made you have to make certain adjustments to the magnetics to get an optimal image. So that argument is completely invalid.
If you're concerned about the high normal operating brightness of the CRT being too much for the camera used to measure MTF, well, ever heard of this thing called a neutral density filter set? Using such an item you can easily adjust the brightness of the image going into the camera to any desired lower level, so there's no valid argument there, either.
The only way to back up your performance claims is with raw and repeateable measurement data using a standardized measurement setup. Empirical measurements "It looks sharper to me" just aren't going to cut it.
If you continue to be resistant to the idea of putting your work to an objective test, then when I go shopping for mods for my own machines, I'll just pass you by as not being a serious player.
Bose corporation doesn't publish technical data on their equipment, saying it doesn't matter. They don't get my business, either.
If you have nothing to hide, hide nothing. Invest a SMALL amount of money in a pattern generator and an MTF measurement rig and put your stuff up for objective evaluation.
I am even willing to help you with the process of locating and acquiring information and equipment required to build your MTF measurement setup. You'll still have to pay for it but I'm good at finding things.
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Tue Feb 16, 2016 6:41 am Post subject: |
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Don't get me wrong, I have no problem with sharing MTF results, but as I don't have a 9" machine, only a 8" whatever I do my MTF results most likely won't convince you about anything  On the other hand I have no problem posting rise time results and scope screenshots of actual setups -and always did these. In fact I have a pulse generator (not a test pattern generator though) that is faster than what Mike Parker uses
_________________
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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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Tue Feb 16, 2016 10:16 am Post subject: |
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| gjaky wrote: | | In fact I have a pulse generator (not a test pattern generator though) that is faster than what Mike Parker uses |
The primary purpose of my pattern generator is FINAL RESULTS. I also can use it for very similar to pulse and Final results because of some of the patterns it has in it.
A pulse generator is fine if ONLy dealing with the bandwidth/speed in the circuit itself. But it cannot reveal the end results (what it looks like on the screen - noise distortions, etc), only a pattern generator can do that or other input source signal device (Blu RAY/DVE,etc).
We also use scope, frequency counter and the same generator to look at the video chain itself...but it ain't finished until it's verified on the screen.
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Tue Feb 16, 2016 10:53 am Post subject: |
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Wolfie posted downscaled uhd material on his 1080p marquee. If you ask me and him it looked better tha HD material.
 image by Radio Head, on Flickr
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Tue Feb 16, 2016 11:19 am Post subject: |
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| redfox001 wrote: | Wolfie posted downscaled uhd material on his 1080p marquee. If you ask me and him it looked better tha HD material.
image by Radio Head, on Flickr |
Wow, that's what I've been telling people for the longest and why there should be no reason for us to be concerned about 4K.
I learned about that at a Barco Seminar in California a few years back. The engineer said because of our screen size, there should be no need for 4K. If 4K source is properly down-rezzed on CRT it should be just as awesome.
BTW, that setup in the picture has my mods in it..
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Tue Feb 16, 2016 11:22 am Post subject: |
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| mp20748 wrote: | | gjaky wrote: | | In fact I have a pulse generator (not a test pattern generator though) that is faster than what Mike Parker uses |
The primary purpose of my pattern generator is FINAL RESULTS. I also can use it for very similar to pulse and Final results because of some of the patterns it has in it.
A pulse generator is fine if ONLy dealing with the bandwidth/speed in the circuit itself. But it cannot reveal the end results (what it looks like on the screen - noise distortions, etc), only a pattern generator can do that or other input source signal device (Blu RAY/DVE,etc).
We also use scope, frequency counter and the same generator to look at the video chain itself...but it ain't finished until it's verified on the screen. |
Did I say anything that is contradictionary with what you say? In these days a $10 VGA card can also serve as a pattern generator from a PC just as fine.
_________________
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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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Tue Feb 16, 2016 11:32 am Post subject: |
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| mp20748 wrote: |
I learned about that at a Barco Seminar in California a few years back. The engineer said because of our screen size, there should be no need for 4K. |
You have brought this up in an other thread already, and this is only half information...
Screen size does not matter at all, what in fact does matter is the VIEWING ANGLE you see the screen.
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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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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Tue Feb 16, 2016 11:49 am Post subject: |
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| gjaky wrote: | | mp20748 wrote: |
I learned about that at a Barco Seminar in California a few years back. The engineer said because of our screen size, there should be no need for 4K. |
You have brought this up in an other thread already, and this is only half information...
Screen size does not matter at all, what in fact does matter is the VIEWING ANGLE you see the screen. |
What.. do you know the entire Display Presentation Industries primary concern is SCREEN SIZE.
It is where the most math is involved in doing and figuring out the proper resolution and what to use there.
Did you know for the longest, just like with PC display, the size of the display is very relevant to the resolution?
Or maybe you should attend one of the seminars, that way you can ask the technology engineers for yourself, why they make such a big deal out of the screen size - I'm done on this one
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