I am a little paranoid that my projection will be crushed with any ambient light, so was thinking about overclocking the LL65K T15 to get a brighter image. With its insanely long lamp life and relatively high color temp, the LL65k looks like a perfect candidate for overclocking!

I know that overclocking:
-Lowers color temp (but the LL65K's color temp is already on the higher end of the range)
-Increases CRI (but how much?)
-Reduces lamp life (but even if a 50% overclock halved lamp life, that's still many years of use)

I also know there are several ways to overclock a lamp:
-Replacing the capacitor on a 400w ballast
-Buying a higher wattage ballast (the next step up I've seen is 600w ballasts, might that be too much?)

So what would be the best method and amount to overclock the LL65k? And how would overclocking that amount affect color temp, CRI, and lamp life?

Thoughts?

Thanks guys!


-Chris

My personal opinion is that overclocking is a proven benefit and plenty safe. Arizonavideo is THE man for info since he was an overclocking pioneer. I simply went the capacitor route. Any downside to overclocking is not that big a deal as far as I'm concerned. Consider some active cooling for your ballast should you decide to implement overclocking.

I read your plog and it looks like you're running the LL65k? "MHDE 400W 6500K Lumenlab"

And you're running this at 500-550 watts you said? (or has it changed since that was posted? hehe sorry, your plog is a bit long and I just got finished with the 14+ pages of AZ's overclocking thread)

How much does the color temp and CRI change when you overclock? (just looking for a subjective rating here)

Ahh I'm still so undecided on what I want to do for my light engine! I think that's the biggest/last holdup in me starting this project..

The lamp I'm running isn't available through Lumenlab and almost certainly won't be available in the future here either. It was a sample I was lucky enough to get my hands on. In the distant future I almost certainly won't replace it but I will make a switch to one of several other options available now or maybe by then something else will capture my interest. I believe the arc chamber is much the same as the lamp being sold here now though. Not certain about that. Yeah, I'm running around 500W. If I documented that in my plog it hasn't changed. As for color I have basically zero experience from which to draw a conclusion or form an opinion so I'm afraid I can't help you there. I'll tell you this though - you should feel free to post a question at the end of the overclocking thread by AV with your specific concerns/questions and another member more knowledgable than am I will almost certainly respond. Finally, don't get hung up on this. It's simple to overdrive later and any reasonable overdrive of any lamp with a reasonable nominal color should not result in a color that'll ruin your final results. YMMV of course. Some are WAY pickier than others.

Edit: Life is short. Dig in and get a projector up-and-running and make changes from there. Don't take as long as I did to get something running.

The color temp wil get lower. It does look like the blue is the first color to get week as the lamps age. The T15 has good blue.

I would get everything running and add some extra power at the end.

A conderner lens will give you more that over driving the lamp so do that first. For a 400 watt lamp it has to be a high heat condenser.

All the T15 I have seen look a little cool or blue so a little extra power will make more red.

You would be the first to do this to the T15. I don't know why others have not tried.

There is a little bit to know but I can help.

I'm sure 450 to 500 watts will be fine even for long term use. If you cool the lamp some. I have run the HQI at 550 watts and that is about as far as the color temp will let you go but it has a lower color temp than the T15.

It may be that driving the lamp harder than 500 watts or so may screw up the color too. I have had some lamps get purple at vary high overdrives.

The M59 ballast is prone to making noise too so making more power with it will make more noise. ( Does the T15 use a M135 or M59?) There is ways around this too.

Sounds good, I'll take your advice in your PM and buy a 4 uF cap. I think I'll pick up a few other caps too so I can test what works best for me in the 400w-600w range. Hopefully I'm not also the LAST person to try overdriving LL's bulb!

I would definitely like to set up a condenser, but every condenser setup I see seems to be using a 330mm rear fresnel for better vignetting. My primary interest is in increasing brightness, so I'll need to mount the condenser close enough to the arc to light all corners of a 15.4" panel with a 220mm rear fresnel. I'm not an engineer and can't trace the light path so I don't even know if that's physically possible, but I'll continue to read some more condenser threads.

In the fortunate event that I am able to use a condenser, I was thinking that a metal heat shield with a circle cut out in the center for some tempered glass would be a good way to keep the heat from getting to the condenser. /thinks aloud: I hear a lot about these things cracking too, so I could even aim a fan right at the little gap between the condenser and tempered glass to get some air moving.

M59. Hmm.. I don't know how much a larger ballast would cost, but if the price is comparable, could I possibly get oh say a 600w and just switch in a smaller cap, thus solving the noise issue? (since the ballast wouldn't be overdriven)

TIA!


-Chris

[edit]
Oh also, might seem like a dumb question, but does overdriving the lamp by say 25% result in 25% higher light output and thus a 25% brighter projection?

Dazzzla has done all the work for finding the corect fl condenser lens.

http://www.lumenlab.com/forums/index.php?s...st&p=134486

A 6x9 condenser should barley work with a 220mm rear fresnel.

T15 uses m59

I wonder how much benefit I'd get from it though. I'm thinking of the used light as a pie wedge with the point at the arc and the wide part at the rear frez. With a 330mm rear frez that's a pretty small slice of light pie, but with a 220mm it's a lot bigger. I'm wondering if a condenser would capture a larger slice of light pie, and if it would, if that increased amount would be significant.

Now I'm getting hungry for pie!

I did a fairly long test setups with a HQI 400 lamp with a 220mm and a 330mm fresnels and a 6x9 condenser lens with LUX readings.

http://www.lumenlab.com/forums/index.php?s...st&p=145895

The 220mm fresnel with the 6x9 condenser was the brightest but had the worst vingeting.

http://www.lumenlab.com/forums/index.php?s...st&p=145895

From what I read it looked like the 6" 400mm FL condenser with the 220mm rear frez was the brightest?

Also, it looked like the brightness of a 6x9 220mm setup was within a few percent brightness of a 6x9 330mm setup, is that right?

Still, I wonder how a 220mm no condenser setup compares to a condenser setup (be it a 400mm FL condenser or 9" FL).

I did test a 600mmx220mm fresnel setup at 550 watts.

http://www.lumenlab.com/forums/index.php?s...st&p=152155


I think the LCD still had antiglare

I should sum up all the readings on the last post. Maybe later.


EDIT
It looks like that link was still with a condenser lens I think I did a test with just a 220mm fresnel but I need to find it still.

So that's 342 ansi with the 220mm collimator and 6x9 condenser compared to roughly 334 ansi with a 330mm collimator fresnel and 6x9 condenser?

It looked like the only setup that made marginally more was the 400mm FL condenser with the 220mm fresnel.

cabe i am in the exact same boat you are in.

either pre con (220 collimator and 15.4 screen)

or overdrive t15

or both? hmmm.

How did this evolve?