Re: NOT JUST ANOTHER THOR MOD !!
Holy Hell! Wow! This is amazing! I haven't been this excited in a long time (I guess I must be a real geek if something like this gets me excited!)
I've been dreaming of making a Maxabeam killer for quite a while now (along with a lot of other people I'm sure), not that it was anything more than a dream. Actually I had been eyeing that particular lamp for use in a Maxabeam killer. Compared to the Maxabeam's lamp it has a shorter arc gap (0.25mm vs. 0.6 something mm IIRC) AND higher luminous output (3000lm vs. <1000lm) resulting in a MUCH higher surface brightness (170kcd/cm2 vs. 30 – 40kcd/cm2 (just a guess based on other lamps XSA lamps in the same wattage range)) than the Maxabeam lamp.
My plan was to swap it out with the lamp in the Maxabeam since the MB is the only light with a suitable reflector (high quality nickel rhodium) and it also had a ballast which may be compatible (constant current DC), not sure weather it would handle the higher operating voltage though. The only problems were the long warm up time and higher colour temperature (I think they're meant to be around 9500K which is meant to be a disgusting blueish-purple).
It's quite a coincidence that you've reappeared just now. I was rereading all your posts about your super dooper Maxabeam only last week, and mentioned you in a post only a few days ago! It was you who taught me (and a number of others) about the concept of surface brightness, and how throw is determined not by lumens, but by surface brightness. Despite your short time on CPF I've certainly learnt a lot from you. (Yes I'm sucking up, but it's true).
OK, question time:
What is the colour like? Is it really 9500K like I said before? How "pleasing" is it compared to the pure white Maxabeam?
How does it warm up? Does it produce any light when you first turn it on? Does the brightness ramp up linearly, or is it more like D2S lamps which produce light when first turned on and quickly reach 80%, and then slowly increases to 100%? I think the name for the curve is logarithmic, not sure though, I'm no good at maths.
In the down the road pictures you can see a large part of the ground being lit up. Is this due to the spill light, or is it part of a much larger secondary beam?
Can you tell me more about the ballast? How big is it? Is it a custom design? How much did it cost? It's funny because it was Marc from AE who first suggested to me about using mercury short arc lamps when I enquired about what lamp to use to make a super thrower. Actually he said that he knew of one guy who had made a spotlight using a UHP lamp, was he talking about you? He said he lived in Florida, you live in the Netherlands, so maybe not.
This might sound strange, but why is it "only" 38 mil cp? In one of your earlier posts you managed to get a 12 mil cp Maxabeam through selecting the one with the best reflector and AR coating the lens. The HBO lamp has 4 – 5 times the surface brightness of the XBO lamp in the Maxabeam, so if used in the Maxabeam it should give 50 mil cp. Now you're using it in a much larger reflector. It has a much larger diameter and is shallower so when taking both these into account the focal length is MUCH longer than that of the MB reflector. So shouldn't this be pumping out well over 100 mil cp?
I gather I'm missing something here. Is the surface brightness of the MB lamp much higher than 30 – 40kcd/cm2? Or is it because the hand picked MB reflector of yours is much higher quality than the reflector you're using in this light?
Why doesn't the beam appear to be any tighter than the Maxabeam? The arc gap is smaller, so given the same reflector it should be smaller, but you're using it in a much larger reflector so the beam should be MUCH tighter than the MB. Is it just because it is so much brighter than the MB it appears larger than it really is?
Some more general questions:
What do you think of the UHP lamps used in projectors? They are AC and have a larger arc gap (1mm), but are twice as efficient, have a lower colour temperature (7000K), but have a similar surface brightness. They can also have a dichroic coating on one hemisphere of the arc capsule to reflect light back into the arc, allowing a much shallower (and thus longer focal length) reflector to be used, which is pretty neat.
I'm not sure of the exact surface brightness, but looking at
this PDF (which is my only source of info in UHP lamps) it appears to be between 100 - 200kcd/cm2, similar to that of the lamp you're using. It also mentions experimental lamps with 0.3mm arc gaps with surface brightness' above 600kcd/cm2!
What is the surface brightness of the 10W Solarc lamp? I know it has a very short arc gap (1.2mm IIRC), but it also has a very low luminous output (not sure if this is the right term, I mean lumens), so I can't see the surface brightness being any higher than standard D2S lamps. Do you know about the larger 21W and 50W Solarc lamps? They have the same arc gap as the 10W, so the surface brightness should be quite high with these lamps (especially the 50W).
What do you think of the Cermax Xenon arc lamps by PerkinElmer? The neat thing about these is that the arc gap is constant for a wide range of wattages, so by the time you get to 800W the arc gap is very small for its power relative to standard quartz xenon lamps (0.97mm @ 800W). Do you think that this could compete with, or even better short arc mercury lamps? Only problem is that these lamps have an integral elliptical reflector which means you would need to use lens optics which as far as I know can't throw as far as parabolic reflectors given the same size. However they give a much nicer beam pattern than reflectors.
Like I said before this light is truly amazing. It LITERALY is my dream light made into reality. OK, not quite, my dream light didn't use the Thor as a host; I planned on either using the HBO lamp in a Maxabeam or in a large pistol grip spotlight like the Lightforce Blitz. I must have this light! I assume you'll be willing to make some more as long as people pay you enough. There's no way I can possibly afford one at the moment, but I am going to do whatever it takes to get enough money for one of these! This hasn't just displaced the Maxabeam from the top spot on my dream light list; it has knocked it off completely. Who could possibly want a puny Maxabeam compared to this? Well I guess the Maxabeam does still have its advantages. It's instant on, has electronic focus, smaller, pure white xenon light, and also produces much less intense spill light due to the lower lumens which is good for not waking everyone up when you use it on the street. But since the only thing the MB is good for is throw, and this monster has it beat there really isn't much use for a MB anymore.
You should post something about this in the HID forum. I know cross posting isn't allowed, but I hardly ever visit this forum, it was only through luck that I found this when I saw the word "Thor" in the last post preview. The HID forum, on the other hand, I visit many times a day.
Well done Ra, you have made something truly amazing!
