JVC D-ILA NZ7 minitest

markymiles

Distinguished Member
A new one replacing it.
Dimming might not only be the lamp, it can also be changed in the ballast, and dust buildup on the optical elements.
Ahhh ok, that makes more sense. 5% loss on the same lamp seems unlikely, after all those hours. More likely a brighter bulb to start with than the new one.
 
Ahhh ok, that makes more sense. 5% loss on the same lamp seems unlikely, after all those hours.
Why, how have your PK-2518 and PK-l2615 lamps behaved from new to used?
 

markymiles

Distinguished Member
I'm basing it on my experience of PJ lamps in general. That's damn good if true, but you presumably don't have the data from the same bulb to compare to?
 
I'm basing it on my experience of PJ lamps in general. That's damn good if true, but you presumably don't have the data from the same bulb to compare to?
What projectors have you tracked light output on from new to many hours later?
 

markymiles

Distinguished Member
I don't have a spreadsheet/timeline if that's what you are asking. Isn't it widely known they dim with age!! The last one I installed a new bulb for was for a JVC X5000 and I measured it a bit like you with a new bulb and the increase was 40%. Can't remember the exact number of hours but it wasn't that many more than yours. I have done the same thing on two Epson's, with similar results.
 
I don't have a spreadsheet/timeline if that's what you are asking. Isn't it widely known they dim with age!! The last one I installed a new bulb for was for a JVC X5000 and I measured it a bit like you with a new bulb and the increase was 40%. Can't remember the exact number of hours but it wasn't that many more than yours. I have done the same thing on two Epson's, with similar results.
what did you use to measure, and do you measure calibrated or uncalibrated light out, you remember 40% thats extreme on that series, ill guess its a very high hour lamp, or maybe there was an aftermarket lamp in it, those tend to be 20% or dimmer from new.

Im using the Klein K10A, still have both lamps.
 

groesbeek

Active Member
Well its all great if you got a good sample, no doubt, but its not fun to get 2 samples with 75% contrast drop in the corners, and dE 15 in color uniformity error with fully closed iris.
You can try setting the iris to -15 on your N7 and put a white test pattern up, ill bet the corners get quite yellow. You might not have a problem with that as you might run it much more open where its not a problem, but people with 90" screen will.
Also had a dust blop on the blue panel on one of them right out of the vox, along with multiple stuck pixels.
No doubt that's extremely unlucky getting 2 projectors that bad, but it happens, even the NZ series goes back with dust blops and defects.

No light path on any projector is sealed, not sure why anybody thinks so.

As you have both the N7 and NZ8 it would be interesting to see the paper test on both your samples.

Here is a N/ example, the dust problem is biggest on hanging units, not so much on standing units
View attachment 1634943
From a post I made in another forum

“Ok so I took some long exposure shots of the NZ8 with DD off and no signal displayed.

This a 10 sec exposure - I assume we know enough about what those are on this forum and don’t go screaming “NZ BRIGHT CORNERS……”

To the naked eye no problems are visible to the naked eye on low or mid. They start to be somewhat visible on high laser.

And absolutely not with DD on.

You can also see some light spill in the long exposure from some of my equipment below the screen that’s beyond my 2:1 cutoff.

Brown Rectangle Wood Grey Flooring
 
From a post I made in another forum

“Ok so I took some long exposure shots of the NZ8 with DD off and no signal displayed.

This a 10 sec exposure - I assume we know enough about what those are on this forum and don’t go screaming “NZ BRIGHT CORNERS……”

To the naked eye no problems are visible to the naked eye on low or mid. They start to be somewhat visible on high laser.

And absolutely not with DD on.

You can also see some light spill in the long exposure from some of my equipment below the screen that’s beyond my 2:1 cutoff.

Brown Rectangle Wood Grey Flooring
Thats nice uniformity, what about the N7 is that also that nice? the fastest way to check dust blobs is with the paper test in front of the lens and press hide. That way you also dont get light from different equipment in the shot.

So did JVC seal the light path on the NZ8 or better dust filters?
 
Last edited:

groesbeek

Active Member
What projectors have you tracked light output on from new to many hours later?
In my case about 8% drop on low lamp from 50 hours to 740 hours on NX7. I had the impression most of the drop was early on. Also Autocal numbers changed significantly.
 

alebonau

Distinguished Member
N5, N7, NZ7…
My screen is 100inch (dont have space for more) in a dedicated blacked out room.
easily Nx7

dont need any more lumens screen this size. will hit adequate lumens for SDR and HDR with using p3 filter and have lumens to spare ... :)

edit the dual iris on the nx7 will help with a 100" screen size as well to crank down and take advantage of the additional contrast :)
 

groesbeek

Active Member
Thats nice uniformity, what about the N7 is that also that nice? the fastest way to check dust blobs is with the paper test in front of the lens and press hide. That way you also dont get light from different equipment in the shot.

So did JVC seal the light path on the NZ8 or better dust filters?
Yes I’ll try the paper test tonight.

Sorry the N7 is sold and I never looked at it that closely TBH, just have got more involved in all this as part of going to NZ8. But I never noticed anything on content on N7.
 

mattkhan

Distinguished Member
What projectors have you tracked light output on from new to many hours later?
I think I had the same thought as @markymiles

Just to be completely clear, your 5% loss is loss attributable to the aging of the projector itself or sample tolerance of the bulb itself. Correct?

My last nx7 bulb had lost 50% over 3500hrs and I think 25% was around the 1500hr mark (+/- a bit, I don't remember exactly). My previous pj was an X3 and i never got anywhere near 3500hrs out of those. A new bulb in the nx7 was basically taking it back to day 1, possibly slightly higher if anything (e.g
SDR was at -12 on iris previously, -13 this time).
 
I think I had the same thought as @markymiles

Just to be completely clear, your 5% loss is loss attributable to the aging of the projector itself or sample tolerance of the bulb itself. Correct?

My last nx7 bulb had lost 50% over 3500hrs and I think 25% was around the 1500hr mark (+/- a bit, I don't remember exactly). My previous pj was an X3 and i never got anywhere near 3500hrs out of those. A new bulb in the nx7 was basically taking it back to day 1, possibly slightly higher if anything (e.g
SDR was at -12 on iris previously, -13 this time).
My test dont take the projector aging into consideration, or calibration differences as running a autocal can drastically change the projector's light output. so it's 2300 hour projector, balance D65 and measure with old lamp, then swap to a new lamp and repeat the test.

I dont operate in "think" i test and know for sure when and why, then there is no guessing and memory errors involved.

My experience with lamps is not a linear light loss, it seems fairly stable over a long period, and then drops rapidly, so i would also expect a 3500 hour lamp to be toasted, but i would expect 1500 hour to perform close to new.

How do you measure/ tools and how do you calibrate it?

Didrik have a lot of experience with high hour Lamp models, maybe he could share some?
 

mattkhan

Distinguished Member
I don't think I have seen that behaviour (slow degradation then a drop) on any bulb though I don't measure/calibrated religiously enough to know exactly how it has degraded over time.

I check it either when I notice it is dimmer or something looks a bit off. Recently with autocal + 3dlut in madvr generated by displaycal, previously just with the lut. Usual sort of kit (i1pro, i1d3) and can't say I have noticed dramatic changes from calibration to calibration or massive losses so I don't believe those are factors in my case but hard to sure of that.
 
I don't think I have seen that behaviour (slow degradation then a drop) on any bulb though I don't measure/calibrated religiously enough to know exactly how it has degraded over time.

I check it either when I notice it is dimmer or something looks a bit off. Recently with autocal + 3dlut in madvr generated by displaycal, previously just with the lut. Usual sort of kit (i1pro, i1d3) and can't say I have noticed dramatic changes from calibration to calibration or massive losses so I don't believe those are factors in my case but hard to sure of that.
The problem can be the autocal, its not unusual to see big light output differences with autocal, so i think all options to track lamp drop/behavior is off if adding JVC autocal to the mix.
You could try put in a new lamp like i did, and measure light with the same projector settings, eliminating all other factors than the lamp. Ill guess most got a extra lamp with the projector, so have one ready.
 

markymiles

Distinguished Member
The problem can be the autocal, its not unusual to see big light output differences with autocal, so i think all options to track lamp drop/behavior is off if adding JVC autocal to the mix.
You could try put in a new lamp like i did, and measure light with the same projector settings, eliminating all other factors than the lamp. Ill guess most got a extra lamp with the projector, so have one ready.

Did you measure the previous lamp when new. Would be more interesting/accurate to measure the drop over time with the same lamp rather than comparing to a new lamp.
 
Did you measure the previous lamp when new. Would be more interesting/accurate to measure the drop over time with the same lamp rather than comparing to a new lamp.
No i did not, as i would never have a projector for 2000 hours its kind of impossible, the best i can do is buy new lamps, compare it to the old one in the projector, again if you want to test the original lamp over time you cant use the autocal, and you have to factor in age of the optical elements, and ballast changes, not all dimming is the lamp, you can have a ballast gone bad, but working, now you have to buy a new projector and start over again.

How do you track/ test lamp dimming? and whats your experience with the JVC autocal, did you notice light output changes using it?
 

markymiles

Distinguished Member
Agreed re the autocal that will obviously skew the results. Surely just measure a 100% white pattern in an uncalibrated profile over time. Easy to do. Other factors may be involved as you say, but think it is pretty accurate.
 
Agreed re the autocal that will obviously skew the results. Surely just measure a 100% white pattern in an uncalibrated profile over time. Easy to do. Other factors may be involved as you say, but think it is pretty accurate.
The autocal works a bit different from model to model, but in general you have to do a full autocal with the factory default settings, like natural 6500Kelvin normal gamma, and that corrects all gamma curves, but the white point not so much, what JVC software do you run, and with what meter?
 

markymiles

Distinguished Member
Why do you always ask questions you know the answer to. You know I don't have a JVC. It's clearly in my signature. I was commenting on how to measure a bulb over time. I said I agree with autocal making it difficult. To be entirely 100% accurate you would have not used autocal at all and just measure a profile that hadn't been changed in any way. Or as you say redo an autocal and factory default. I have an i1display pro by the way, which has offsets compared to a ref meter.

Either way the whole point of this discussion came about as you said you'd only lost 5% over 2000+ hours compared to a new one. It's a very very small loss and haven't heard anyone reporting as such as plenty of people have suggested a much bigger dimming over time on the same lamp. So there's obviously the possibility of either the old bulb being dim to start with or the new one being a bright example.
 

mattkhan

Distinguished Member
The problem can be the autocal, its not unusual to see big light output differences with autocal, so i think all options to track lamp drop/behavior is off if adding JVC autocal to the mix.
Certainly a risk though, as I said, I don't recall material steps in output after (re)autocal (it is the sort of thing that would make me redo it and/or look into what was going on) but I don't write these things down so can't show any data in support of that.
 
Certainly a risk though, as I said, I don't recall material steps in output after (re)autocal (it is the sort of thing that would make me redo it and/or look into what was going on) but I don't write these things down so can't show any data in support of that.
I think the environment the projector is running in is quite a big factor on lamp life, the cooler intake air the better, if its in a small room under the ceiling it often heats up the room quite fast, and recycle the outlet air into the intake again, reducing the cooling drastically, and lamp life as well, so it will be hard to make any general lamp curve, im sure the same goes for the laser units, with electronics heat is the killer.
 
Why do you always ask questions you know the answer to. You know I don't have a JVC. It's clearly in my signature. I was commenting on how to measure a bulb over time. I said I agree with autocal making it difficult. To be entirely 100% accurate you would have not used autocal at all and just measure a profile that hadn't been changed in any way. Or as you say redo an autocal and factory default. I have an i1display pro by the way, which has offsets compared to a ref meter.

Either way the whole point of this discussion came about as you said you'd only lost 5% over 2000+ hours compared to a new one. It's a very very small loss and haven't heard anyone reporting as such as plenty of people have suggested a much bigger dimming over time on the same lamp. So there's obviously the possibility of either the old bulb being dim to start with or the new one being a bright example.
So your discussing technical details and JVC autocal behavior, have never owned own or calibrated a JVC projector, tracked light output on any JVC?

I have also heard about JVC projectors running 3000+ hours with minimal loss, and others with 500 hours with no light left, so if we all press our ears up against the wind listen to the sound of it we might get the answer, by all means, don't own one or get any hands-on experience.

Would you say 3rd hand information/ rumors, and no hands-on experience with the topic discussed is the right way to find an answer?
 

markymiles

Distinguished Member
I accepted that autocal affects the results and said so. However it appears I am not qualified to discuss bulbs dimming over time then according to you.

I have owned a JVC X5000 and unlike your 5% increase I had a much higher bump in brightness with a new bulb. Similar hours to yours. Same 265W bulbs that they have used for a long time if I am not mistaken. Both JVC originals, not some cheap copies. I accept results vary and yours is clearly then a lucky one hardly affected by degradation over time like most. Really didn't need this much discussion it just came across as quite remarkable.
 
I accepted that autocal affects the results and said so. However it appears I am not qualified to discuss bulbs dimming over time then according to you.

I have owned a JVC X5000 and unlike your 5% increase I had a much higher bump in brightness with a new bulb. Similar hours to yours. Same 265W bulbs that they have used for a long time if I am not mistaken. Both JVC originals, not some cheap copies. I accept results vary and yours is clearly then a lucky one hardly affected by degradation over time like most. Really didn't need this much discussion it just came across as quite remarkable.
As mentioned i also think the environment the projector is running in has a big effect on the lamp life, as well as low vs high lamp mode. did you measure the X5000 from new, and how was it used?
How many hours on the old bulb when you changed, and what was the difference?
 

The latest video from AVForums

Maverick UK Premiere IMAX Review + Top Gun, Tom Cruise, Tony Scott and 4K + Movie/TV News
Subscribe to our YouTube channel

Latest News

LG UltraGear Gaming Monitors get VESA certification
  • By Ian Collen
  • Published
Sony confirms UK pricing for A90K and A75K Bravia XR 4K OLED TVs
  • By Ian Collen
  • Published
LG announces new CineBeam HU915QE 4K laser projector
  • By Ian Collen
  • Published
Movies Podcast | Maverick IMAX Review, 4K Disc News and More
  • By Phil Hinton
  • Published

Full fat HDMI teeshirts

Support AVForums with Patreon

Top Bottom