#61
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Here is my CTC-7 with grey faced 21CYP22, with Philco 21FBP22 green faced tube sitting on top. The monitor to the right is a Sony security monitor, with NTSC comb filter decoder.
http://www.videokarma.org/showthread.php?p=2998927 Grey faced 21AXP22 has similar color to the CYP tube, where anything with a green sulfide set of phosphors looks more orange-red than true red to my eye. We'll see what the green faced 21AXP22 in the CT-55 ends up looking like, I assume it will have similar response to a 15G.
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#62
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Nick,
I guarantee you it will be nothing short of DAZZLING! I hope some day you can get up here with Mark (he needs to make a trip to get his 21" roundie safety glass) so you can see first hand what a wonderful picture a CT55 will produce. But Murphy's law says if you come by it will blow a fuse. Bob
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Vacuum tubes are used in Wisconsin to help heat your house. New Web Site under developement ME http://AntiqueTvGuy.com |
#63
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[QUOTE=Tomcomm;3003530]...I read somewhere the modern SMPTE phosphors are more orange/red since they produce better "flesh tones" with less accurate chroma demodulators...QUOTE]
I was on the SMPTE monitor committee, and I can tell you that the colors were standardized based on what was available in the tubes made with controlled phosphor batches and supplied in Conrac monitors. In "SMPTE C primaries," the "C" stands for Conrac. The relatively slight variations in red phosphors over the years has little effect on flesh tones compared to the changes in green and blue, especially green. |
#64
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I didn't know that.
Sitting on that committee must have been a very interesting time. #;^) Cliff |
#65
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Quote:
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Audiokarma |
#66
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That's the plan, anyway.
What I want to do is have the green AXP, grey AXP, CYP, and green FBP all measured. I have date codes for all of them, so it will be interesting to see the progression of phosphors through the years. Ultimately I would like to have a database of them all built up, so we can see what response they have in order to shed some light on the exact colors a person will see when they use a certain tube in their set. That way, we can replace subjective things (what people's eyes are seeing) with something objective and concrete (at least within the limits of the instrument). Only then will we be able to say 'tube x does in fact have an orange-reddish phosphor, where tube y has a more correct color.'
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#67
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Sorry about that. Was on the road after ETF and just now saw the X2 flub,
Pete |
#68
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I think testing all those tubes would be a good idea. But you should test in a way that normalizes all the tubes. For example, use a simple light meter to set all the tubes to the same or very near the same overall brightness level. Use the same method to make a white screen on all the sets. You would have to use the same equipment on the test of each tube. I think it would also be neato to include some of the 23" and 25" tubes from the 60's through the end of crt production in the tests as well.
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Yes you can call me "Squirrel boy" |
#69
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Quote:
All the tubes would have proper greyscale tracking before the test, along with purity and the whole bit. Every effort will be made to ensure a valid test occurs.
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#70
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Just got outbid on a used I1 spectroradiometer on ebay - would have been a good price if it sold where I stopped. Maybe some other time...
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Audiokarma |
#71
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That sucks. Oh well, this is already going to happen it's just a matter of when!
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#72
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Back to the subject at hand...
I recently discovered that I hate metal polishing. But I can't argue with the results. The trim around the CRT window is badly tarnished, so I set about fixing it. First I tried a buffing wheel and compound, but that didn't even faze it. The stuff is just too old, and covers 100% of the trim. Plan B- I wet down some paper towels with vinegar, and draped them over the trim overnight. It looked like hammered dog crap when I woke up, but some polishing stuff buffed the light surface corrosion right off. After that, I hit it with some Never Dull and holy cripes does it look good now! I mean, it's literally a MIRROR SHINE. It's gonna take many more hours of work to get the rest of the trim pieces done, but results like this are well worth it in my book. Think it's a good idea to hit it with clear laquer after I'm done? I don't want to do this every year... Apologies for the pics, they don't do the brass justice. A shine like this is hard to capture with a camera.
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#73
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Clear lacquer can keep brass nice for a long time. It may be a little trickier to spray lacquer on shiny metal than on wood. Little uh-ohs jump out at you.
This may sound nutty, but wax can also be used. When I had a guy restore some antique light sconces, he added a couple of little new switches. He dipped those in gun bluing to make an aged color and then used Howard's Feed 'n Wax over all of the brass, old and new. I was skeptical, but this was about 10 years ago, and they look exactly the same. Phil Nelson |
#74
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Lookin' good Nick! That trim looks new!!
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#75
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Nick,
Although this method does not produce a Bright High Mirror shine, this is what I do. To get a nice brushed satin finish, I remove the tarnish and corrosion using 3M Scotch bright wheels on a polishing arbor. It leaves the finish looking like it has been buffed with steel wool, sort of a satin finish. This process takes about 1 hour on the polishinhg arbor for the exact same trim as on your 21CT55. I did the trim for the Hallicrafters CTC4 clone in just this manor yesterday. If you however want a higher luster, the next step is to hit it with 0000 steel wool. Then I always spray with clear nitroceluolose lacquer. I have also used clear ACE brand enamel from Ace hardware with good results. The Ace brand leaves a heavier coat, but it is a bit trickier to work with on a high luster finish. The trim I polished up yesterday had been subjected to moisture over a long period of time. As a result there are microscopic pits in the surface that are the color of copper. (brass is mostly copper, usually 90% or more) The tiny pits show up more if the surface is polished to a bright luster mirror finish so, I dedided to use a brushed satin finish because it looked better and the pits are less noticable. I am not sure what the correct finish is. Is it a bright mirror finish or a brushed satin finish? In any event I have used the brushed satin finish on a couple other sets and it looks quite nice. Bob
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Vacuum tubes are used in Wisconsin to help heat your house. New Web Site under developement ME http://AntiqueTvGuy.com |
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