( EDIT) Please If you want to over drive a lamp talk to some one who knows how and be carfull ,don't leave it unatended. Most lamps will not let you double the powe like this one, they will melt and fail also read overclocking lamps and ballast in extreme mods.

I found some cheep 175 watt HQI lamps on eBay for less than $20.00 it is a made in China lamp. He does not have any more listed but I bet he can get more. It is a small RX7 size lamp with a 21mm arc and a 10K color temp.

I really wanted a 250 watt but could not find one cheep enough. I am going to over drive the lamp to 200 to 225 watts with cooling. I mainly want to see what happens to the color temp and what picture looks like.

A few pictures.

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The standard RX7 socket from a shop lamp may work but it is too short so I will make it longer.

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I don’t know if a 250 watter comes in an rx7 package I didn't see one on eBay.

If this works we could have a good cheep lamp for a small PJ. The 21mm lamp arc should be fairly efficient and a 250 watt ballast can be had for cheep (I would use a 250 not a 150 there may be some adjustments needed on the ballast wait for trsting.) add a cheep socket and a surplus shed condenser lens and you might be able the have a whole light system for less than $100.

I do expect it to be a little blue but a slight adjustment of the RGB will fix that.

I won’t be able to start the testing for few but I may use it for a test light in my PJ so I don’t have to use the 1200 for setup.

just my 0.2

RX7s(not -24) is ONLY aimed at 70W(and -24 for 150W) HCI/HQI bulbs

chinese noname HQI's must be avoided, they have no UV filtering at all(even if it says UVSTOP on the bulb itself, it might be weak or non-existent), and even if you got a lexan or whatever, the light leaks can scr*w your eyes up big time, and also god knows about the explosion hazards

the temps of brand name lamps are already bullsh*t to begin with, being around 10/20% higher or lower....or more, and it keeps ever changing before and after burning out...so 10000K on a chinese noname means NOTHING

finally, you're really not supposed to make a rx7s(-24) holder any larger, the bulb is supposed to be sitting neatly inside of it and I really wouldn't advise to do it

get a RX7s-24 150W OSRAM Powerball 4200K and enjoy the show

"

Where do I start?

"RX7s (not -24) is ONLY aimed at 70W (and -24 for 150W) HCI/HQI bulbs"

The spec sheet list a RX7 socket, the socket I have is good for 500 watts I made it longer so the lamp will fit.

Next time I will ask you first so I will know if it will work.


"chinese no name HQI's must be avoided, they have no UV filtering at all(even if it says UVSTOP on the bulb itself, it might be weak or non-existent), and even if you got a lexen or whatever, the light leaks can scr*w your eyes up big time, and also god knows about the explosion hazards"

First China is a country most people capitalize the name of a country. The lamps do say they have UV block. The SD400 that LL sold for years had no UV block. I have a lot of lamps that have no UV shielding I would list them all but you’re still learning so I will let you find out on your own. The lamp has two shells that one better than a HMI lamp.


"the temps of brand name lamps are already bullsh*t to begin with, being around 10/20% higher or lower....or more, and it keeps ever changing before and after burning out...so 10000K on a chinese noname means NOTHING "

And you would know this how? Have you ever tested one made by this manufacture? I can control the power to the lamp so I can adjust the color temp too. We all know the color temp changes.

"finally, you're really not supposed to make a rx7s(-24) holder any larger, the bulb is supposed to be sitting neatly inside of it and I really wouldn't advise to do it "

The lamp fits inside the lamp holder, it would be easer to by a RX7-24 if you want to but for testing this socket is fine. Did you see what I did? I started a sentence with a capital letter!

"get a RX7s-24 150W OSRAM Powerball 4200K and enjoy the show "

If I'm right the Powerball is about $60.00 and is only 150 watts I have been running the inferior lamp all night at about 250 watts.

If you don’t have any thing positive to say It might be better to just keep it to yourself

I fired up the 175 watt lamp tonight on M59 400 watt PS ballast. I would guess the power level to be around 250 watts but I will find the exact level later.

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I had a large fan over it to cool it and the arc was stable with no movement at all.

The color temp is still fairly high it looked like about 6500k to 7000K but it's hard to be exact. I took a picture of the roof with two lights on it the yellow light is a 3200k lamp and the other is the 175 watt HQI.

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I need to burn the lamp for a few hours to see how much the color temp will drop but it was almost OK even now.
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I will have to find the exact power level before I go any further. I think the lamp could take around 250 watts and still have a 2000 hour life. This is short but the lamp is cheep and the size is nice and small for the smaller triplets and PJ. I paid $17.00 shipped for mine.

I have a nice 5x7 crown glass condenser that should work good.

A few shots of the lamp burning.
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I made the lamp mount exactly the same size as my MHI setup so I may use the smaller lamp for all the adjustments and test before I install the big lamp.


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Don't forget numbers AV

I'd say something positive if there was anything positive to say about low quality chinese noname HQI's.
I could give u a URL to a german shop that sells 6000K HQI's with Short Arc for $15, but they have to be real junk for the price, "there ain't no mistery" as we say

I was being friendly, I don't really care actually

Well, some ppl don't seem sensible to UV's, I am.
They give me bad headaches.

I've read many benchmarks that show that for instance sometimes 6500K lamps run at 8000, and the opposite as well.

But I won't bother finding the URL's considering you are so knowledgeabe

Powerball costs $35 here in europe and I should get mine next monday, sorry for that

Maybe all the UV rays from the "Cheap Chinese" lamps are making Arizonavideo grumpy.

Just joking AV don't take it personal.

Has anyone tried to detect UV with the UV Security embedded in some Currency or Credit Cards?
Not sure what spectrum of UV is detected.

There is a certian amount of fun with a cheep light that can be over driven.

Boys just want to have fun.

This is called a test. Some day all the lamps will be ceramic or one of the PJ makers will start making one for cheep.

There is a chance that a over driven cheep lamp may work fine.

Have you actually read anything that AV has done? I'd put him right up there with
Elken on this board on people that are knowledgeable about the lamps we use for
the projectors. So it just comes off a little condescending that you're spouting your
"facts" at him, I'd assume that's why he reacted that way.

If you have light leaks that are so bad it's hurting your eyes, you should consider
asking for help with constructing your enclosure.

And as for my two cents, I've bought plenty of stuff from China that has no identifying
marks from a manufacturer that have worked longer than their counterparts from
other countries. Most of the time your brand names put their name on someone
else's product, anyway... so who's to say where the brand names product came from?

Oh yeah, AV is the man when it comes to overclocking. He actually was the one who taught us about the longer rear fresnel application. Using his idea with a pair of 317mm fresnels in the standard lens setup and a precondenser I was able to get 185 lumens then later 240 lumens by adding mikyd's Plus Rite 6500k bulb. So really, you'd be surprise to find many experimenters here who have contributed quite a bit to DIY pj's.

Seriously, we should make another catagory just for experimenters and their work for easier researching. I bet some of the newer members would be surprise.

They did they call it extreme mods. (My plogs keep getting moved there)

At this point overdriving the lamp is no shock and not really the point here. This is a cheep blue light. That might give better performance than let’s say a SD400 and it is small and lower power so it might be a better match for a standard lens setup.

Will it be better than a 150 watt ceramic? I don’t know and that is why we do what we do.

A 250 watt ceramic should be a better lamp but they are larger and cost more.

Let’s say you want to make a supper small double fold PJ with a 10.4" LCD on the cheep. The only lamp that will fit is the T6 lamp package. I only see two lamps the 150 ceramic and the overdriven 175 HQI. There is a good chance that the HQI at 225 watts will be a lot brighter and even cheaper.

Will it look better than a ceramic? I don't really think so but we will have to see. Remer were talking about a lamp that I paid $6.19 for.

I may do a large test of 4 or 5 lamps at once

The HTI 1200 A $190 lamp
The MHI1200 A $180 lamp
The HQI 2000 A $180 lamp
The HQI 400 A $70 lamp at 550 watts
The HMI 575 A $40 or $90 lamp


The 175 HQI A $16 lamps

Life is tuff when you’re the runt!

There is something about cheep that I like.

If I can get 200 ANSI out of the cheep light and allow for a smaller box that might be cool.

If the 175 lets you a standard condenser that’s a plus too for cheapness.

This is all about cheep.

The last picture of light looked bad this the roof again with two lights the 175 and the 3200K


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I burned the lamp for a few more hours today in hope that some of the blue would go away and it has.

I setup up the amp meter and found the power level the lamp was running at and it was way too high!

The make two types of the 175 watt HQI lamps one is a 95v lamp like the 150 watt HQI and one is a 150v lamp. Well the one I have is a 150 v lamp made to run on M137 ballast. This higher voltage of the lamp means the ballast will make a lot more power into the lamp.
The lamp is running at 485 watts

I can change the power level and I will reduces it to around 350 to 400 but I think this is an extreme overdrive and not really a good idea for the most part so I have asked to have this thread moved to the extreme mods area.

My main concern is still the color temp at the power level we want to drive the lamp at. I am sure that at less than 250 watts or so the lamp will be way too blue. At 485 watts it is now around 6500k. It looks vary white with the sun shining in the room. It is still a little blue but not too bad. It looks like the T15 a little.

I set the lamp behind two Fresnel and projected the arc image on to the screen for a comparison with a known light temp. Both the lamps in the picture are 3200k lamps but the camera always white balance on the 175 lamp and not on the halogen lamps.


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For this lamp to last any amount of time the power level will have to be reduced. This may vary likely make it too blue. You will then have to turn down the blue on the LCD and this waste light.

I will do more testing with this lamp after I get my test LCD setup.

I re setup the test box with a used LCD it is a 18" westinghouse with a bad ffz on one side. This makes foe a blank strip on the left side. I used the OSD to set the rez to 1 to 1 and then set the desktop to 1024/768 This gave a screen smaller than a 17 but larger than a 15" LCD. I will list the exact size later.

I ran the lamp all day at 400 watts with no problem. The color temp is now around 6500k. I know this by having sunlight come into the room and the color is vary close.

I have the small altman reflector which will worl with this small lamp so I used it and I cut the 330mm for my main PJ so I only have a 220mm/600mm setup which was fine with the 6x9 condenser and the smallwe lcd size.

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I really did think I would have a blue push with the lamp but all was OK witn no color adjustments.

The color of the lamp is not great but OK.

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This is a white screen it looks more even in real life but it also looks just as white.

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A color test pattern.

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And one more girl.

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And now about the brightness. I have a lux meter and I'm not afraid to use it.

The screen is 61" x 46"

The readings were

21 37 26
28 52 29
33 57 33
Stray lux is about 3

Avrage is 35 lumens.

Screen is 1.8M so 35x 1.8 =63 ANSI

The screen does not look dim the colors are bright and there is a fair amount of stray light.

This is the room with the PJ running.

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And the test box.

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At first I though the lamp would not look good at 400 watts but I was wrong. The short arc does give nice contrast and focus.

I an using the spare 450mm triplet and it is not quite as sharp around the edge focus. I have both an old one ( 1960) and a new one ( 1980) The old one looks better to me.

This setup is new to me so some inprovments could be made but I don't expect the lux to go up much

I like it . If that box was sealed of, it would be a close to perfect picture.

Also...If your concerned about the edges being dark, you could spray the light compartment with a clear white paint. Iv heard of people doing that and the picture isnt dark at all.

I don't really know what this means. The 18" triplet has no problem with dark corners. Painting the light box will make no change in the light output unless you have no reflector.

I am going to do a larger test with three 10k lamps, the 175 watt and a 250 watt and a 400 watt all oven driven.

it woul just help with the brightness on the edges of the picture. But....... the 3 bulbs would take care of that

Let me rephraise that.....You could paint the intire box, behind the panel, white. And it would brighten the corners.