CurtPalme.com Home Theater Forum

[km987654]

I was just looking at the 1292 LC housings I have and noticed that the corners of the tube are obscured by part of the LC tank so it would seem that the max image area is considerably less than the max tube face area. This is different to the Barco and Ampro tanks I have that have no obstruction which would suggest that you could use more of the tube face with the latter two producing longer tube life. Is this really the case or have I missed something?

[kabuby77]

You're right it's well known. If you use 4:3 AR you waste some lateral area, but if you prefer 16:9 you don't care about corners.

[km987654]

[kabuby77]

Yes surely, but it depends on the aspect ratio of the screen you're using. If you use 16:9 screen when watching 4:3 material you have to tighten on horizontal width, on the contrary if you have 4:3. Since the majority of people today uses panoramic screens the question about the corners is less important. It would be interesting if someone had produced 1.85:1 tubes.
I have 120" 1,85:1 setup , if I expand the image to 1,33 it becames too bigger for a comfortable vision.

[km987654]

[km987654]

Are the G90 LC tanks much bigger than the 1292? They appear to be larger in pictures I have seen and if so this would have been done to expose more of the tube face which would suggest the 1292 housings were too small.

[kabuby77]

Mmh, I don't think there are too much differences, it would be useful to hear the opinion of a tecnician like Curt that had seen the tubes disassembled.

[km987654]

[Graham Johnson]

The `292 tubes have the ability to use MORE of the tube face than almost any other tube. The limitation isnt the corners on MEC tubes isnt phospher area but the angle of the neck bell. MEC tubes ALWAYS use less of the tube face due to the electron beam hitting the neck/bell junction before the face. Therfore you have to run a reduced area to stop this happening.

The SONY tube bells are very big in comparision and can run phospher right out to the edges with no issue.

[zGman]

Well I don't know much about 1292's, but i don't have any trouble running
large phosphor area on my BG1209S and MEC tube BG808S LC...certainly not
hitting the tube neck - i think that was more of an issue with the small neck
tubes in the nex xg's and g70's

G

Oh and it is very nice to hear from Graham again - hope you have been well,
thanks again for the two 1292 focus coils years ago!

[km987654]

I don't have any problem accepting that Sony tubes can display an image as large as the phosphor what I am saying is that the 1292 LC tanks have an obstruction in each corner of the tank caused by the lens flapping system used. This means that you cannot use all of that phosphor. Looking at non lens flapping Barco tanks they have no obstructions but the actual mounting point of the tube covers part of the phosphor so even though you can make an image as large as the viewable phosphor area this not all the available phosphor. The only LC tanks out of the three types that I have that will allow you to use all of the available phosphor are the Ampro tanks as they use only the very edge of the tube for mounting and there are no obstructions in the tank itself. The only thing I would like to know in the case of the Ampro tank is does the image become obstructed simply because it has to pass through a round lens and therefore you cannot use all of the available phosphor with these either. Perhaps someone with an Ampro could chime in here.

[Graham Johnson]

I re-read you original post and misunderstood your question.

IIRC the phospher on the tube face isnt 4:3 its actually taller. The Phospher is framed by the inner surface of the tank which has a blanking type arrangment around the edge.

SO by the time you display a full size 4:3 it actually doesnt use the top anyway. BUT as a few people have said 4:3 ?? who uses it ?? 16:9 FTW !!!

Cheers everyone. I do come on reasonably often, but I just usually just lurk not contribute. I do find it rather comforting that all my old mates are still here.

[km987654]