Well-Known Member
im sure theres already a thread about these but i didnt see it.

which one is better?

last year we switched from FLK to FEL in our 15.3 degree Strands and 12 degree Colortrans. Are there any other 1kw lamps that work better?

also, why are all the newer lekos using 575w and not 1kw?
i'm not sure about the difference between the fel's and the flk's, we always used fel's in our strands.

as far as only using 575w now, there are 2 reason's.
1) the optics and reclectors are much more efficient now, and so can provide the same amount of light, and usually more than the larger lamps in the older lights.
2) with using the 575w lamps you can put 3 or 4 ( I can't remember it's been a long day) lights on a dimmer instead of 2. Which give you a lot more flexibility.
Ok, you guys are obviously not reading my posts.

Ah’, but since it’s my own pet speciality in the industry, here we go.

Simply said, stop using the FEL. In a general search short of having model numbers to the fixtures, the lamp probably is rated for both of them in wattage. The reason I would not continue usigng it is the FEL lamp by way of filament is more like a MFL par when being used for a spot purpose than a lamp of any directed beam of light. The filament size is large while the efficiency is fairly low. The FEL is old school in use for times when normal EHD/EHG lamps were not intense enough. It’s also second generation in lamps after incandescent ones, and we are about into the fourth. The lamp exchanges bulk wattage for filament “point-source” usefulness in efficiency when used.

This would also be a reason why newer fixtures don’t use this lamp. Better lamps, more refined filaments that also allows for more refined optics on the fixture.

Beyond this filament size and efficiency, more modern lamps take advantage of 115v verses 120v operating characteristics on a typical lighting system where after a dimmer and long cable run, it’s doubtful you will be still seeing 120v at the fixture. Given a 120v lamp that will never see this voltage, why have a lamp rated for it given “amber shift.?” Amber shift is what happens when the lamp does not operate at it’s rated full voltage and thus it’s dimmed down to something less than that even if at full intensity on the dimmer. With Amber shift, since the filament is not warming up as hot, it than is much more amber in color and intensity.

The 115v lamp on the other hand given a base average of 118v to the fixture operates over it’s rated voltage most often. This means that while the lamp life goes down in being more expensive in some conditions to use unless the long life version in balancing this, it’s also operating with a hotter filament than what it’s specs are rated at in providing much more intensity and color temperature. This in addition to a smaller and more efficient filament that allows the optics of the light to send out a more efficient and refined beam of light.

Long story short, according to the adds, it’s a 575w. FLK/HX-600 lamp that looks as if it’s a 1,000w lamp in these fixtures. This is in part due to the better optics on the SL and Shakespeare type luminaries they were designed around, but on older fixtures, it’s only putting out about 800w worth of light. Certainly not in say a Altman 360Q as much as a 1Kw FEL in it. (Note the 360Q was never rated for this wattage of lamp.)
The look of a 800 or 1,000 watt lamp is also because of the higher luminous output of the improved lamp, plus it’s operation at an over-voltaging condition. These in addition to the smaller filament size meaning more light gets directed out the front of the instrument.

In comparison for older fixtures you ask about, the 575w. FLK looks in many ways like a 750w EHG, or a 575w. GLA long life lamp given the GLA is a third generation technology smaller filament size in being more efficient than a FLK much less EHG. They might match up to a FEL lamp somewhat in output, but only because the FEL has a large filament with much of the light provided trapped by the baffles in the fixture. At best, let’s say the FEL is worth a 900w lamp in these fixtures that is using up 1,000w in power and turning that last 100w in heat. Such heat destroys lamp bases, wiring and thin pieces of aluminum like reflectors.

Since such lamp details about specific lamps optically in caparison not on my part scientific study, such lamps compared to each other are estimations on my part with what is going on with the lamp and optically. My intent is to make it understandable this opinion of the FEL I have.

Remember that there is a difference between apparent intensity most retailers will cite in calling the 575w FLK as bright as a FEL and actual light produced even after voltage drop considerations they factor in. The 575w lamp simply is not going to be able to produce as much light as a 1,000w. also halogen lamp in reality. The standard FEL is rated at 120v for 27,500 Lumens. The FLK at 115v is rated for 16,500 Lumens. Again due to the lower voltage at the fixture, you will probably never see 120v/27,500 lumens from the lamp. Much less once the larger filament in the fixture has it’s light hitting the reflector, much of the light will be directed into stray directions instead of focused out the front.

On the other hand, since the FLK is burning hotter and beyond this, it having a more “point source filament” in being more efficient, it will by way of a hotter filament, and the slight over-voltaging on it become a brighter looking beam of light. This is both due to over voltaging and higher efficiency. This color (temperature) appearance when more blue... higher color temperature while it does not reflect the actual light produced, is still brighter in it’s nature. What is brighter, a halogen lamp off a Leko, or a follow spot lamp? Intent with a follow spot - at least those not also using FEL lamps, is to be brighter than the surrounding stage lighting. The follow spot often is not lighting up the target more, it’s just a brighter beam of light.

Ok, we have a 575w lamp that appears to be doing the job of a 1,000w lamp at least in being more efficient. At least in a fixture that takes advantage of the refined optics of the smaller filament. For your fixtures, a standard FLK/HX-600 on paper won’t be exactly as bright as these 1Kw FEL lamps. It’s going to be often close enough however and given the Wiko brand FLK, cost almost half as much as a FEL.

Something mentioned on Stagecraft list a few days ago was the little kernel of knowledge about lighting of yesterday not needing to be as bright as lighting of today. This means that your fixtures will have given halogen based fixtures been designed to fit a EHD lamp, than go EHG in wattage for brighter lighting. The FEL by yesterdays standards was an over-rating/over-kill of the fixture for use in stuff that needed to be even brighter than the rest of the stage. The white light of a halogen lamp as opposed to that of a incandescent light was also seeming to be white as opposed to by todays’ standards the dim incandescent of yesterday in comparison to the FLK.

In other words, the incandescent lamps of the 40's thru 60's were pleanty bright for those standards. Fixtures were improved along with lamps to fit a more efficient halogen lamp these FEL lamps are a part of. Now we have at least a third generation in technology in having a smaller more efficient filament and a lamp that works at a voltage closer to what it will be given.

In other words, second generation lighting fixtures in a world that wants to have third and fourth generation lights doing the trick. The FEL lamp has become a sort of standard sort of in forcing more light out of the fixture that’s really designed to put out a much dimmer light due to yesterday’s standards. Still, pop later third and fourth generation lamp in a second generation fixture, and it will often outshine the much higher wattage second generation lamp. Might even outshine a third generation fixture if you have what I call a end of third or early forth generation in technology lamp in these second generation fixtures.

This HPL/FLK series of lamp is third generation. Given today’s standards require higher intensities, just as with the 500w EHD lamp having the 750w EHG as a alternative, the 575w FLK lamp also went 750w in having more punch. These 750w improved lamps now have the punch of a lamp over 1Kw but a little less than 1.2Kw. Given this lamp’s better output, it will in a second generation fixture you cite, have the same output about as a FEL if not much more due to the refined filament.

For this fixture the GLD/HX-754 lamp will be a high output lamp very similar to the FEL only it will have a better color temperature, smaller filament area meaning more light will actually get out of the fixture, thus more luminous intensity given improvements in technology. The long life GLE/HX-755 than will have, or should have about the same at 750w, intensity or at least color temperature adjusted seeming light output as a FEL but last much longer. There is some doubt that there will be the full intensity, but as with a stage full of even incandescent lamps, and the audience used to it’s intensity, once you have all the luminaries replaced with the long life 750w lamps, you will get used to the intensity. Given these are long throw lamps, the 750w range of either long life or high output would probably be best to use. Use the FLK as a minimum for shorter range lamps, and the GLE for the long throw.

On even better yet lamps than the above, we get into a seeming late third or early fourth generation in lamp improvements over that of a incandescent stage and studio lamp. The Color Command fixture for instance as mentioned elsewhere on the forum I think, uses a lamp that’s similar to the GLD, but much better in output. Otherwise at 575w, the Osram HPR lamp has a little piece of metallic reflector stuck inside the bulb. While simple and a seeming cheap thing to do, it really improves the efficiency of the lamp by 15 to 20% as advertised. In other words, consider the ellipse shape to a reflector. Consider that hole in it’s reflector given the lamp has to get into it somehow. Now consider that internal reflector in finishing the arc of the reflector.

Even on a second generation Altman 360Q series of fixture these Colortran and Strand lights will be similar to, you now have a more efficient lamp both in filament and finishing the reflector’s arc to a more perfect ellipse reflection.
One of my pet projects since I was raised around them is in defending the Altman 360Q series of fixture as being more than ancient crap. Good fixture, once you pop a HPR lamp into one, it in comparison to a ETC S-4 fixture, the Altman due to a less efficient optical system will have a less balanced beam of light, but still you can see the second generation fixtures’ light beam inside that of the third generation S-4 beam of light given the same wattage. The Altman 360Q in a test kicked the rear on a ETC S-4 fixture.

Given this new about fourth generation of lamp - the HPR 575/115v, we now just about have a lamp that easily in color temperature but also in output could no doubt be just as bright as a FEL lamp for only 575w. Don’t know for sure, and have not tried it, but it sounds a reasonable observation.

Beyond this is the 750w Color Command lamp the Philips #6981P, that with it’s small filament and high efficiency probably will outshine a FEL lamp due to even more output than a GLD and a more efficient filament than a FEL. Given even it operating hotter, this lower wattage of lamp than will save money and dimmer space and preserve the adverse effects of heat on the reflector or fixture more. Given a Shakespeare verses ETC S-4 assumed to be the same type of fixture in general, and the HPL 750w/C being about the same lamp as the GLD, the Color Command lamp in a Shakespeare fixture will out class the ETC fixture in intensity and output. ETC thus once realizing that the HX-600 lineage of lamp is no yet dead no doubt will put extra pressure on the lamp manufacturers to improve the HPL lamp in becoming more efficient.

Unfortunately the patent on the #6981P lamp is held by Philips as a brand and in having a bad experience with rated lamps for fixtures and licences with their removable heat sink to work with S-4 fixtures, Leko Lamp GLA/GLC which would work both in a S-4 and Shakespeare both, it was never accepted by ETC thus they eventually discontinued the lamp. So much for a standardized lamp. Philips recently finally just bought the rights to manufacture a HPL lamp. They are now producing a 1990ish version of the HPL lamp, perhaps much better than that given improvements to pinch seals but in being late in the game lacking the ceramic heat sink. The removable heat sink GLA was a good lamp, just never accepted.

Given the GLA/GLC Philips at one point came out with that had a removable heat sink so you could use it on any Leko, I took the sink off one and tried a FEL in a S-4 Leko fixture. This is how I can verify that the FEL is just a big wattage huge filament lamp, but not efficient. A 1Kw FEL in a S-4 fixture next to a 575w HPL lamp in another S-4 fixture. The HPL had no problems in outshining the FEL. Could not even get a good beam of light out of the FEL lamped fixture.

In any case, the FLK is a better in general lamp to the FEL. Better in efficiency, much less you can have four per 2.4Kw dimmer as opposed to just two. In these long range lights will they produce the same output? No, other than color temperature it won’t be as bright due to Lumens in light.

If you find it necessary to have as much or more a intensity as a FEL, I would go #6981P Color Command lamp as a direct replacement. Otherwise I would go with the GE/Thorn GLE/HX-755 lamp in a longer life but hopefully similar output lamp. Hmm, 300 to 375 hours verses 1,500 hours, at some point you have to balance lamp life with output needs. You can always go Color Command lamp, but first try the long life GLE lamps.

Otherwise one might try the Osram HPR 575w lamp first even before the GLE. If it is not bright enough, you could use these test lamps for your shorter range Leko specials in providing a cleaner image on Gobos. Well worth the investment as such lamps are supposed to provide a great image. Have not tried a gobo on such a lamp much yet. Only done so once but it was on an opposing side of the stage to the one with the FLK. The fixture with the pattern that was lamped with the HPR did a nice clean pattern still. Just could not confirm if better than that of the fixture with the FLK.

Given the HPR is more a start into the fourth generation in lamps, and Osram is working on a long life equivalent that will eventually replace the Philips GLA as the best long life best lamp possible for second, much less third generation fixtures. Osram in their new HPR lamp with complexities in just inserting a reflector into a lamp is developing a long life equivalent but beyond this is also having problems with inserting the reflector into a S-4 HPL lamp to date. At this point there is no expected HPL lamps with internal reflectors possible.

Osram HPR575w lamps like the Philips #6981P 750w lamps in having highly efficient gas/filament mixtures. Much less the HPR with that ellipse completing internal reflector. These lamps are the next and most modern generation in technology up until the point where halogen gas even when supplemented by xenon gas becomes some form of liquid filled incandescent lamp such as used on the most modern of projector lamps at this date, and will in competition with LED lamps, be the next generation of incandescent lamps TBA. For your second generation luminaries, I recommend these two fourth generation lamps to replace the FEL. IF these fairly short life/high output lamps are too short in lamp life to be efficient, than I would either go with a Wiko brand of FLK in something that’s cheap but fairly efficient for another short life lamp, or a Philips GLA lamp for a long life lamp that will have a little less output but 5x the life. Otherwise in 750w, the GE/Thorn GLE.

Directly answering your question also, Osram some time ago came out with the FEL-R, #54582. It’s discontinued but it in having a internal reflector also, it’s a fore runner to the HPR lamp and would have that 15 to 20% more efficiency as a direct replacement to the FEL lamp. They also had the FEL-HR lamp #54584 which while not discontinued is a IR-heat lamp. Great stuff for doing UV-Light as an option but also something that given it’s a heat lamp will probably fry the fixture. Other than these two versions of the FEL, there is no other improvements. The FEL like the EHD, EHG and newer FLK in my opinion are dead lamp lines and 10 years from now will no longer be made by many companies. Because no other companies offer improved FEL lamps, Osram it would seem is a leader in FEL lamp technology even if in earlier years and no longer made. Given they discontinued the FEL/R, there is no hope of a upgrade elsewhere.

Review closely these lamps above. Remember the Philips 750w #6981P or Osram 575w HPR lamps for high output and about the same life as the FEL lamp. Otherwise, in possibly closer matching the FEL, go with the GE/Thorn GLE/HX-755 lamp in having about 2/3 the output but a lower voltage and 5x the life. Too bad Ushio stopped producing the HX-800 lamp, it was better than the Thorn version yet.

Otherwise in second generation lamps, at least there used to be the 1Kw, Osram #54590 at 2,000 hours in life, and while still the next best, still not as much as the FEL. Today as with many other pre-HPR lamps, it’s gone. I seriously doubt there will be any further upgrades. You can go 1.2Kw if absolutely necessary but why bother, it’s not necessary.
(After scrolling up then back down again) Holy crap I read all that?

Ship, you're my hero.

For you people out there who pass out when you see so many words in one place, he said:

FEL sucks;GLA=bright, short life;GLE=less bright, long life.
That's kind of what I said in forgetting the HPR. This after re-editing.

GLA = long life and when Philips - the best lamp you can possibly use for a 575w long life lamp. Otherwise if 750w is needed, the Thorn/GE GLE long life.

For high output but similar to lamp life to the FEL, the Osram HPR is advanced technology though simple in doing so, or the Philips #6981P for 750w designed for the HES Color Command in being the best 750w lamp on the market.

Altman for a vendor is considering and testing both lamps for adoption into acceptable standards in their fixtures. Adaption and acceptance of these lamps unlike the Philips GLA with heat sink that did not get far with ETC in destroying their trade mark world, is expected with Altman just as they accepted the GLA/GLC over the HX-600/FLK for use in their Shakespeare fixture.
That was without a doubt the longest post I've ever seen on any internet forum. I read it all, and but I'm still not entirely sure what you said.

Let me know if this is right:

You recommend not using FELs anymore because while they produce more lumens than any other similar lamp out there, their filaments are huge and innefficiant. By using newer lamps with smaller filaments, you harness more of the light output, which compensates for the reduced intensity. Furthermore, FELs burn really hot, which can shorten fixture life. What I didn't get was which lamps you recommend for someone who is looking for the same light intensity as the FEL.

Last year, on the advice of the friendly people at Gopher Stage Lighting, I embarked on a campaign to replace all of our FEL lamps with HX601 lamps, thinking that they had the same light output. When I was in there last month, I was shocked to find out that the HX601 actually had only about 10% the output of the FEL (3050 Lumens vs 27500 Lumens). It also cost almost twice as much, but had five times the lamp life. I had been wondering why our washes didn't seem as bright as they used to, and I though I had found the culprit.

It now appears that there is another factor that determines the light output of the fixture: filament size.

Looking at the spec sheet again, the FLK/HX600 is looking like the best choice.

Oh, and as far as instruments, we're using 360Qs and CCT Shilouette zooms (I can never spell that right).

What do you recommend?
You obviously did not read my post about soft flats. LOL. At least you read the whole thing and some things did help. Later when ready to learn more, there is a spark in your head that will open up when ready to learn more or at least have something click within your head that there was something you once read about it that raises a question.

3,050 Is the color temperature of a GE as it’s called FLK/LL or HX-601 Part Number #39730. It’s actual output is 12,800 Lumens.thus 46.5% of a FEL. By the way, the FEL is not the most powerful lamp you can in voiding the listing on a 360Q fixture rated at 750w put into it. The Ushio JCV 120v-1200w/CH at 33,000 Lumens will surely fry lamp base, wiring and reflector much more efficiently than that of a FEL. (Did you note the FEL lamp is not rated for use in a Altman 360Q fixture?)

The reason they recommended this lamp is because of the efficiency and lamp life and it being a standard lamp in the industry at the time for normal settings such as yours. It would certainly pail in comparison to the FEL as you say but the FEL is not a normal lamp to be using for other than long distance throws. Were these comparisons on the original post not long range in the discussion, I would say you have too bright of lamps in the fixtures in general if you need FEL lamps in all of them. - The goal is not to necessitate sun tan lotion as makeup. More fixtures equal a better and more even painting of the stage with less intensity needed in each. Much less with the 575w lamp you can put four per dimmer as opposed to two with a FEL. Hmm, per dimmer you now have 51,200 Lumens at a higher color temperature as opposed to 55,000 Lumens but again a lower color temperature. Even before we correct for the differences in voltage, that’s a fairly close match in output given the four times the life in the HX-601 over the FEL.

They also in recommending the FEL replacement seem to have bought into the hype of a FLK/HX-600 lamp being as bright as a FEL. As said above, it’s not really - more like a 800w lamp. The HX-600 series just burns hotter in color temperature in seeming as bright as a FEL. They than forgot to deduct for the long life lamp reduction in output further in telling you to expect this in exchange for the longer life. Given “everybody” calls the FLK the same as a FEL, them giving you the lower intensity long life HX-601 lamps as being a little less bright but similar was a simple and honest mistake.

Match this up with most of the above new lamps such as the GLA, #6981P, HPR and GLE you and no doubt them have never heard of and I can see the confusion. Much less given these lamps were not really on the market much yet a year ago and most are not advertised, it’s easy to see why the boys at Gopher (never heard of them) would not know much about them. Remember I buy about $100K in lamps per year at about 2/3 your cost given dealer and volume discounts, thus have to know about such things even if I don’t have any primary fixtures that use such lamps in the inventory. Ask me how many versions of the at one time discontinued Emulator lamp are on the market and that’s also my job to know - much less the differences between each of them in output.

Let’s lay it out simply and specifically.
The #6981P as the best lamp on the market is a 750w/115v lamp with a almost similar life and Luminous Output of 20,500 Lumens at 115v as opposed to at 115v, the FEL having a lamp output of 26,551 Lumens at the same voltage given a longer life.
Do the math, for each 1% in voltage drop on a lamp, the luminous output will decrease 3.6%.

Now factor in that the FEL has a filament area of about 7x18mm and the #6981P has a filament area of 9.5x9.3mm. Given a Ellipsoidal Reflector Spotlight that in the best of circumstances would optically perfectly refine a 1mm x1mm source of light, bells and whistles should be going off in your head considering the filament sizes now. You have a 18mm filament verses a 9.3mm filament. Since the Luminaire is putting out a round beam of light, how can a 7x18mm filament possibly not block at least part of the 18mm part of it’s light beam at the gate? Certainly this huge filament when it hits the reflector over a dispersed area is bouncing all over the place and being stopped by the fixtures’s gate thus turning into heat. Simply put if you were holding the lamp outside of the fixture, the FEL would still put out more light. Pop it home into the fixture and the #6981P will at least equal but much more likely out class the FEL in luminous output much less color temperature. This given the color temperature of the FEL also dropped 0.4% per 1% change in voltage and both for their rated voltage start out in the same place.

Your stats will be about similar no matter what voltage you have at the fixture.

Given the #6981P high output 750w lamp outclasses the FEL, one, as your friends at Gopher short of doing the math than could assume that a long life third generation in light source such as the GLE/HX-755 lamp given it’s 1500 hours and 17,400 Lumens in output would have about as much output as a FEL given it’s 4x the life. However, since the filament area is not stated, I cannot confirm the Thorn/GE lamp will be equal. Nor while I have one in the inventory have I had the chance to test this. I would expect that given this lamp was invented in the 21st century however for it to have a more compact filament than that of a 1970's FEL invention that is more a improved BWN lamp than designed for use in a Leko.

Finally in keeping it somewhat short, I don’t really recommend either of the two above lamps for other than long distance throws where the law of squares applies to light beams. Again, re-read how art was created with incandescent and even gas lamps by the above designers at a much lower intensity. If you have FEL lamps in your 6x9 much less 4.5x6 up to the 6x16 fixtures, you have over killed your light to the point it’s way too bright and in non-blinding light, most of these lamps are probably highly dimmed anyway. Much less the theory of amber shift in dimming them I presented elsewhere and earlier on this forum (now that you are interested) where by a 575w lamp will be much more bright than a FEL once you get to say 75% and other dimming ratios. (Do a search into the key word spike.)

So for normal usage we get the HPR lamp that’s basically a FLK or GLC with a internal reflector that completes the ellipsoidal reflector hole in it’s center and produces thus 15 to 20% more light than a FLK. Nope, it’s still not say a FEL in output, but still a much more efficient source of light than most other 575w lamps. With this as has been tested, the 360Q fixture with a HPR lamp had a beam of light you could clearly see within a ETC S-4's light beam. I would un-scientifically say it was a more intense beam of light than that of the S-4.

So for the best high output lamp on the market in a normal wattage, go with the Osram HPR575/115v lamp. Given this is high school or theater and lamps cost more money than the budget allows for, I otherwise recommend the long life Philips GLA lamp in having a smaller and more refined filament than a FLK lamp thus a little more output (see above) in getting almost as much light out of the fixture as a FLK but in a much more cost effective lamp. The Philips GLA lamp is my overall choice for a cost effective general Leko lamp above other versions of it.

Simple enough?
Ship, i gave that post to someone i work with. she was wondering where your experiance comes from for all of that knowlege. do you mind sharing that?
FEL, EHG and the similar "coiled-coil" filaments are designed fro the traditional Altman 360Q and similar ellipsoidals. The are rated at 120 V, and come in various wattages and color temperature vs. lamp life trafeoffs. Rugged, but not as energy effecient. BTW, Altman 360Q is not UL rated for the 1000 watt FEL.

FLK is a 115 Volt 575 watt "energy efficient" lamp designed for the same instruments that accept FEL or EHG lamps. More lumens per watt, but more expensive and more senstive to mechanical shorck when lit.

GLA, GLC (and similar) are designed for the new Altman 360Q "super reflector". All new Altmans come through with this redesigned reflector and your can buy them for retrofit of older 360Q's. (We have done that on most ot ours, BTW). This is as close to Source 4 performance as you can get from the venerable 360Q. Voltage rating of 115 V and rated at 575 watts. Again more lumens per watt but more fragile. The difference is that GLA, GLC has the "projector lamp" style filament design of the HPL lamps used in the Source 4's. The filament design needs to match the reflector design for optimum light output and flatness of field.

Use GLA in your "super reflector" equipped Atlman 360Q's and FLK-LL (long life) in your older ones.

-- Dave
While I was reading Ship's post I was thinking about lamp life. I tend to give up some brightness for lamp life when I pick a lamp. The question I have is how does normal dimmer settings affect lamp life? I tend to run long life par lams at full and I tend to max out the dimmers at 75 to 80% on my FOH ERS (EHG or HX600 lamps) The thinking is it will make the lamps last longer. But as I think about how the lamps work I wonder if I am cheeting the redepositing affect? Am I ok running them at full too? Is the 80%thing just a throw back to first gen lamps?

Personally, I have a warm up cue (well, sub for me) that I run before turing the lights on. This brings everything up to 30 percent slowly (about a 25 count) holds it there (wait of about 15) then fades them out (fade of about 10).

This warms up the lamps so that they are less likely to blow if/when I bump them on to full. This also gives me time to go from the booth into the stage area and check to make sure all of the instruments are on and functioning correctly (make sure focus didn't drop, lamps didn't blow, circuits didn't die, etc.)

I don't know if this is really your question, but thats what I do to increase lamp life (or at least try to).
tjbaudio said:
...think about how the lamps work I wonder if I am cheeting the redepositing affect? Am I ok running them at full too? Is the 80%thing just a throw back to first gen lamps?

From what I have read, it is only at low settings that you will cause the base of the filament to become weak and finally fail prematurely. So at 80 percent I would not imagine that you are cheating yourself of any lamp life.

Also, I am not sure if this problem only occurs if the lamp is underpowered for a significant period of time. Unfortunately, it is not something that I understand fully. I regularly have lamps dimmed at 50-60% on the channel and 80% on the master and have not noticed a difference in the lamp life between those and the ones running at a higher threshold.

In fact, a threshold of 80% is often used and I must admit that I am one who tends to keep my master at or about 80% Although, this is more of a load type issue than a consideration of lamp life I would suspect. I know that is I do load my dimmer up and then back off to 80% I will not come close to overloading the circuit. I also know that I do have that extra bit in reserve if I need to use it.

zac850 said:
Personally, I have a warm up cue (well, sub for me) that I run before turing the lights on. This brings everything up to 30 percent slowly (about a 25 count) holds it there (wait of about 15) then fades them out (fade of about 10).

This warms up the lamps so that they are less likely to blow if/when I bump them on to full.

Most dimmers will have a setting that will allow you to send a small amount of voltage to the lamps to pre heat them. On some this is an internal setting on others, you may find a sensitivity setting. You should see the filament glowing inside the lamp.
Some thoughts:
Ship, I too am truly impressed by the volume of lamp knowledge that you store away. I have to say though that I wish your fingers got tired of typing !, as that was a very long post to read !.
One thing no one touched on was that with 1000 watt lamps, you could only load up a 2.4kw dimmer with 2 units (typical practice - not recommended practice in some instances), vs. 3 @ 575 with newer lamps. This is a huge difference when you don't have a DPC or Dimmer Per Fixture system.
This was one of the early major advantages to 575 watt lamps, as well as the overall design efficiencies.
Remember that it's not like someone went out to design a replacement for the FLK. It was more a desire to improve everything currently in use.
We are talking early 1990's here, when the Altman 360Q with an FEL was the standard ellipsoidal fixture used (though not - of you were smart, in a 4.5x6.5 or 6x9, when the lens would fail).
The Source 4 fixed a number of issues - the primary that the 360Q was not rated for 1kw and when using the FEL, resulted in attending issues with premature color fading (a HUGE issue on labor expensive shows such as any long running Broadway event) as well as as socket failure.
Additionally, the gobo's took a beating and glass gobo's would not function in a 1kw rated unit.
And of course, gobo rotators would not get invented until the S4 came along with it's accessory slot.
The S4 with the improved and efficient filament as well as the glass dichroic reflector fixed most of the heat issues as well as allowing things like gobo rotators and glass image gobo's.
The FLK and the other lamps that followed for the TP22 socket were a need by the other manufacturers (Colortran, Strand, Altman) to get around the proprietary HPL lamp design while getting some backwards compatibility to existing sockets.
The move to the 575w lamp also spawned the availability of grants from local power authorities to reduce power usage. More then a few theaters in New York City were able to replace a chunk of their inventories this way, The Lincoln Center State Theater, the City Center as well as the Joyce Theater come to mind.
Yep, old topic and I'm sorry on the origional post that I was it seems to me in re-reading taking as harsh a reply (thin skin at times...) Pet project of mine to replace all FEL lamps in the industry with more modern ones, this much less correct the HX-600 equals 1KW mythology. More like 800+ watts at 115v instead of 120v, plus better color temperature and a more refined filament that makes it seem as bright.

Short enough? My wish often not well placed is to esplain, and that at times goes too far in total explination of to the extent I understand.
Ship, i gave that post to someone i work with. she was wondering where your experiance comes from for all of that knowlege. do you mind sharing that?

Have her contact me off line at my e-mail. I don't list nor think it necessary or should where I come from become important as to from what I speak. My experience in the industry is of me and not all together from where I work given most of what I learn is from study and a breadth of experience amongst places. Nor do I wish where I work to weigh on my comments or to have my comments weigh on where I work - that's a corporate type thing and a me type thing. Not hidden but not stated or emphisized. Again, sorry about the harsh innitial post in defence of my thoughts on it.
A G9.5 is also a medium two pin base, they are the exact same, just classification lingo

The former being the normal US type usage of this lamp base type - easily confused, the other the more modern and becoming standard Euro type classification of the lamp using Euro Metric norms. 9.5 meaning the pins are 9.5mm on center. G meaning bi-pin, no GX or GU or GZ and other sub-letters meaning that it's both round pins to the base and there is noting blocking or spacing the pins from going all the way in or fitting into a "TP-22" base also another American term for base type I tend not to use much.

Euro terms for lamp base classifiactations are something to get used to but really good to learn. Much better system. A BA-15d is much better than
"Dual Contact Bayonet" for descriptiong - this given indexing types and normal types under the same general description and other lots of what's that term type descriptions. Hate the metric system, like them for lamps in general. Most of my notes are metric and I like it that way in being accurate, much less not having to convert inches to descimal equivolents when needing an accurate measurement.

Guess the industry is stuck with 1/8" increments when it comes to lamp globe type such as PAR 38, yet otherwise when possible using metric to be accurate.
My thoughts--

>>So for the best high output lamp on the market in a normal wattage, go with the Osram HPR575/115v lamp. >>
This lamp is LONG discontinued. We haven't made it for over 10 years.

Personally, I prefer the 575W and 750W lamps.

575W comes in two Flavors (Filament design) - FLK (CC-8) is a short version of an FEL that is more efficient and compact, and because it is 115V vs. 120V for the FEL it burns hotter and has a slightly higher color temp. GLC is a 575W 115V lamp with a C-13D coil design. Same coil box size, but instead of one big coil, the filament design is many smaller coils like springs on a trampoline.

There is a long-life version of each (FLK/X and GLA) that has 5x the life at ~30% less lumens.

There are also 750W versions of the GLC/GLA, which are the GLD (300hrs, high output) and GLE (1500 hrs., lower output).

Personally, I HATE the CC-8 coil design of the FLK/EHD/FEL style of lamp. They are prone to fail when bumped due to the sharp angle that the filament takes coming off the mount.

For me, I'll always go with the GLC (575W) or GLD (750W).

NEVER go with Long Life unless you are going to run them at full all of the time and won't ever need the extra output (For example- if these are being used in an amusement park or Las Vegas, running 24 hrs a day). Here's why- If you get the High Output lamp (GLC/GLD/FLK) you can ALWAYS make it a long life lamp by dimming it. Dimming a lamp makes it last longer. BUT-- unless you are Spinal Tap, you can't dial your lightboard up to 11, and overdrive a long-life lamp to make it a high-output short-life lamp. By getting the High Output lamp, you have more options and can use it for maximum output, or run it at 90-95% and now you have the equivalent of the long life lamp in terms of output and lifetime. Give yourself (and your designers) more options!
I have a case of HPR lamps in storage. What if any is their shelf life, and or given zero sales, (don't retail a lot of lamps) should I give them away before retiring and getting back into theater in say 15 to 20 years than buying them?

Agree for the most part above but a GLA is a better option than GLC in my opinion as prime modern lamps. Reason is as with the past, the audience will find bright enough with the lumen level on stage is presented a 1,500 to 2,000 hr lamp. Bang for the buck and getting lamp changed, the longer life lamp is better in not changing as much, and might get a tax credit. One should stock the GLC for specials etc. in getting that extra punch in short of going 750w, but an overall sense of toning down wattage and having a very high head room for going "11".
Last edited:

Users who are viewing this thread