CurtPalme.com Home Theater Forum

[sdubreuil]

Hi all

I need you opinion on this.

If will look at the spec of the Sony 1251 on this Curt web site, this PJ is capable to do 720p.

Somewhere else on this site, Curt says that 720p need 50MHZ of bandwidth but the 1251 do max 40 MHZ of BW. I'm now confused.

Is that meaning that the 1251 will just barely do 720p?
If yes, if I add the Module DD and DE to convert the 1251 to 1271, is this will help? The 1271 have 75MHZ of bandwidth. Those modules will also increase the convergence point from 9 to 21.

I have a source where I can get those modules for $190 for both. Should I buy them?

Best Regards
Stephane

[AnalogRocks]

I have a 1252.
720P looks soft. It can be done but it will look soft. 1080i looked much better.

I have run my 1252 at 1440 x 960P the scan lines overlap and make the film from DVD look smoother.

It's very watchable if you dont mind a soft picture.

Maybe someone with a 1271 can pipe in about how they look at 720P

[AnalogRocks]

I have a 1252.
720P looks soft. It can be done but it will look soft. 1080i looked much better.

I have run my 1252 at 1440 x 960P the scan lines overlap and make the film from DVD look smoother.

It's very watchable if you dont mind a soft picture.

Maybe someone with a 1271 can pipe in about how they look at 720P

[Mark_A_W]

Just buy a Marquee or a NEC or something for a few hundred bucks....

[AnalogRocks]

Where's the challenge in that Mark?

[AnalogRocks]

Where's the challenge in that Mark?

[sdubreuil]

Thanks Analog rock for your pertinent feedback
Do you believe the soft image is cause by the low bandwidth of the 1252?

Stephan

[Mark_A_W]

[AnalogRocks]

There's two factors with the 127x and 125x series. The first is Electrostatic focusing, the beam width can only be so sharp with this method. The second is lens quality.

The tubes used in these machines can't resolve sharply, the signal at 720P. Also I notice the picture looks much sharper on the face of the tube than what is projected onto the screen.

So no I don't think it's a bandwidth problem I think it's a tube problem.
It has been said the most these macines can resolve ( that is so you can still see the scan lines ) is between 600 and 7oo lines horizontal in 16x9 mode. 4 x 3 mode you can probably resolve a little more than that.

There's a set up document for these projectors made by an AVS forum member.
See here: http://www.curtpalme.com/docs/Sony_1270Q_CRT_Projector_Setup_Manual_April.pdf

He says somewhere between 600 and 700 lines in 16:9 mode and likes 666 lines.

I run mine now at 1022 x 600 and scale everything to that resolution except regular TV which I run line double at 640 x 480 or off the HTPC at 1024 x 768.

[AnalogRocks]

There's two factors with the 127x and 125x series. The first is Electrostatic focusing, the beam width can only be so sharp with this method. The second is lens quality.

The tubes used in these machines can't resolve sharply, the signal at 720P. Also I notice the picture looks much sharper on the face of the tube than what is projected onto the screen.

So no I don't think it's a bandwidth problem I think it's a tube problem.
It has been said the most these macines can resolve ( that is so you can still see the scan lines ) is between 600 and 7oo lines horizontal in 16x9 mode. 4 x 3 mode you can probably resolve a little more than that.

There's a set up document for these projectors made by an AVS forum member.
See here: http://www.curtpalme.com/docs/Sony_1270Q_CRT_Projector_Setup_Manual_April.pdf

He says somewhere between 600 and 700 lines in 16:9 mode and likes 666 lines.

I run mine now at 1022 x 600 and scale everything to that resolution except regular TV which I run line double at 640 x 480 or off the HTPC at 1024 x 768.

[sdubreuil]

wow very nice info Analog Rock, I will follow this document.

I'm a bit confused on something. If I have no performance gain by adding the DD and DE board on the 1251q, why the ranking of VPH 1271 is higher then the 1251q?

The DE and DD boards are the only difference between the two models.

Thanks again
Stephane

[tony359]

that cards give you more convergence point, so the global convergence will be more accurate. If you read on ranking, there is wrote that projectors in the same section are very similar in performances. 1251 and 1271 are very near so don't expect much differences between them!

Ciao
A

[Bob Brown]

What about the video path. The 1271/1272 are supposed to have more bandwith than the 1251 in addition to the convergence enhancements.

[ecrabb]

I'm surprised nobody's asked the OP how many hours are on his 1251.

The 07mp and 07msp tubes in the 12xx series were reasonably sharp when they were brand new, but as AnalogRocks pointed out, they had their limits. What I'm surprised that nobody has mentioned is that as these (and other ES-focus) tubes accumulate hours, they'll get softer and softer. I've heard with these machines, that even if there is no visible wear at all on the tube face, that even at 6,000 hours they could be soft enough that most of us wouldn't want to use them in our HT's.

So, Stephane, how many hours are on the tubes on that old girl?

As AnalogRocks (I need to find out what your name is!) also pointed out, depending on what lens you have, you'll lose sharpness there, too. I'm not sure how the PT-43 and PT-65 compare, but it's been shown how much sharper then PT-65 is than an HD-8 Rev B.

Also, setup is really critical on these machines to get a good pic. Get a magnifying glass, put some sunglasses on, turn down contrast (a bit if you have to), and look at the image on the tube face and compare to what you're seeing on-screen. If the image on the tube face is a lot sharper, you have lens and/or setup issues to work on.

Oh, and what kind of screen and what size are you using.... and therefore, how hard are you driving contrast?

Finally, I much prefer 1080i on my 1271 to 720p. It's sharper and just looks better. With my last quick setup on a crap screen, I could just start to read Windows icon text at 1080i - so I'm finally getting there. A more thorough final setup, better lens adjustments, and a better screen, and I think I'll have an image I'll be pretty happy with. Not an XG or a G70 by any means, but not bad for what I'll have in it.

SC

[Spotmatic]

[ecrabb]

I should have been more clear. When I said, "these machines", I was referring primarily to the 12xx's and the Sony tubes as getting pretty soft over time. Certain other ES tubes to a lesser extent. The 708s and the Panasonic P16 tubes are probably what, at least a 5-year or so newer chassis and tube designs than that of a 801s or 1251/71 with 07mp's or 07msp's? So, I'm not that surprised that you got a nicer pic out of the 708 with high hours than the 801 with relatively low hours.

So, I still doubt you could get a 6,000+ hour 07mp or 07msp to make an image that most of us would consider sharp or would be happy with in our HT's - especially given what a nicer EM-focus projector could be had for, not to mention the near bumper-crop of cheap or practically free ES-focus machines now.

SC

[sdubreuil]

Hi ecrabb

I will return to you with the hours but I know that is less then 6000 and even probably less then 5000. This PJ is in pretty good shape.

I know that my blue is out of focus. I will fix this one this weekend.

My Screen is a Dalite Cinema Vision High contrast 96". My projexctor is at 13 feet from the screen.

http://www.da-lite.com/products/product.php?cID=20&pID=96

I very like all the pertinent info that you all give me but please keep also the focus on the initial question. Is a 1271 will do a better job compare to the 1251?
I have the oportunity to buy the DD and DE boards for $190.

Why do I ask this?
Because it is look like the 720p and the 1080i need a bandwitdh of 50 MHZ. The 1251 has only 40MHZ while the 1271 has 75MHZ.

Look at this page under Bandwidth description
http://www.curtpalme.com/Projector_Rankings.shtm

Thanks a lot participating to this debate.
Stephane

[ecrabb]

I could be wrong, but I would guess the bandwidth difference between the 125x and the 127x was a marketing spec rather than an engineering spec. Curt's 125x/127x tech page says:

[Bob Brown]

Stephane

I know the neck boards for the 1271 are different than the 1272. I would question that simply replacing the DD and DE boards would add to the video bandwidth. So I will suggest after researching if there is enough improvement to warrant going from a 1251 to 1271 that you consider simply purchasing a 1271/1272. I have seen many go for 100-200 dollars on ebay. And if the CRT(s) need swapping then just put in yours and do a full setup.

As Ecrabb eluded, low contrast setting and exact mechanical are crucial to achieve highest performance with these machines. I have a 1271 with 8900 hours on the Red and Green Tubes Blue replaced and unknown.

For reference against your 1251. I will post some pics in a day or two. I am in the middle of comparing a "dialed in" 1271 versus a Not so dialed in 9500LC (I'm workin on it!). I just moved the 1271 so I need to do another mechanical. I run 1600x1200 (due to few choices on my HTPC's SOYO Motherboard built in video card) and I can just read the single pixel font text well enough to navigate windows from 16 feet on a 9 foot wide screen when converged. I do get a little convergence drift. Overall picture is excellent IMHO. For best quality I run the contrast between 36-40 in a pitch black room.

[Bob Brown]

Sorry one other comment about scan lines. IMHO you must find a balance between no scan lines or barley visible scan lines up close and having good on off pixel performance across the entire screen. Any scan lines even just notiable up close will cause aliasing which ruins the image for me. I like the film look. If I wanted aliasing I would buy digital.

[AnalogRocks]

Sdubreuil you have the projector too far from the screen. Maximize the RGB width by looking in the lens with sunglasses 8) on and set the RGB width to within 3/8" of the edges. Do NOT scan the picture off the edges of the tube.

Then move your projector forward until the image fits the screen. I think my 1252 was about 11.5 feet from the 96" screen we were running it on.
Refocus and redo the convergence. Make sure you are running the final resolution you plan to run at when you do this.

As for getting the other boards. 21 point convergence would be nice but you can get pretty close with just the 7 point.

Is it worth $190 it's hard to say. A 1272 in excellent shape can be had for $700. So it's a tough call.

[AnalogRocks]

Sdubreuil you have the projector too far from the screen. Maximize the RGB width by looking in the lens with sunglasses 8) on and set the RGB width to within 3/8" of the edges. Do NOT scan the picture off the edges of the tube.

Then move your projector forward until the image fits the screen. I think my 1252 was about 11.5 feet from the 96" screen we were running it on.
Refocus and redo the convergence. Make sure you are running the final resolution you plan to run at when you do this.

As for getting the other boards. 21 point convergence would be nice but you can get pretty close with just the 7 point.

Is it worth $190 it's hard to say. A 1272 in excellent shape can be had for $700. So it's a tough call.

[Mark_A_W]

If there's no difference in the boards in the video path. There's no difference in bandwidth.

NEC did this all the time...played with the specs for marketing reasons.

$190 will buy you half of an EM projector these days.

I don't think a 1271 is any better than a 1251.

[AnalogRocks]

[AnalogRocks]