8mm Forum: ESC / EJL BULB

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Posted by Mark Norton (Member # 165) on September 21, 2005, 04:20 AM:

Only one ESC left now, so i've swithched to an EJL. Now, I have a small basement cinema with a 10 ft throw on to a 8 1/2 ft cinemascope screen and have been satisfied with the brightness , in high setteing, from the genuine ESC. The General Electric EJL's dont't cut it and are noticably dimmer. I've read the reviews in Film for the Collector and also have heard thet the Derann ESC's are re-badged EJL's. As Genuine ESC's are no longer available what are GS1200 owners using now and what is the next best to a genuine ESC?

Posted by Kevin Faulkner (Member # 6) on September 21, 2005, 07:07 AM:

Mark, EJL's are the only alternative. DONT use the A1/252 (250W) as it puts a strain on the transformer and you dont really get more light than a genuine ESC. The filament is designed to cover the 16mm gate. The ESC has a tighter filament bunch to concentrate the light onto the 8mm gate. Also the 24v/250w lamp tries to draw more current than the transformer can deliver with the result that the lamp voltage drops and therefore gives less light. Stay safe and use the EJL's.
What I would do is to shop round for EJL's and try different Brands such as GE, Osram and Philips to name a few. I think the brightness varies between manufacturers.
I have found some of the Philips lamps to be particularly good in their output and eveness.

Kev.

Posted by Mark Norton (Member # 165) on September 21, 2005, 10:32 AM:

thanks Kev,

I will try & get hold of a phillips, how do you rate the Derann ESC?

Posted by Tim Christian (Member # 48) on September 21, 2005, 10:33 AM:

Mark, I am a bit puzzled: my Chinon 350 fills an 8' 'scope screen very nicely with an EFP lamp. In fact, based on that, I'm just upgrading several projectors to 150 W in the expectation of filling a 12' scope screen.

Obviously projector and screen efficiencies vary very widely.

Posted by Mark Norton (Member # 165) on September 21, 2005, 10:45 AM:

Since upgrading to this GS1200 I have only used genuine ESC Bulbs, it's when I swapped this bulb for an EJL I could notice a drop in brightness. Even with the EJL it is still a nice bright picture. As I have only the one ESC left I am saving it for shows rather than general use.

Posted by John Clancy (Member # 49) on September 22, 2005, 01:43 AM:

Derann no longer stock the EIKO ESC as it wasn't very good. As has been stated many times on this forum, some of us that tested it suspected it as a rebadged EJL.

Tim, the EJL lamp still provides a brighter picture than a 150w lamp of other machines. What Mark was saying was he's noticed a fairly significant difference going from a decent ESC lamp to an EJL. He's absolutely right.

Posted by Kevin Faulkner (Member # 6) on September 22, 2005, 04:04 AM:

I think there are two things about about the ESC. 1, I mentioned above that the Fialament bunch is tighter on the ESC than the EJL so it's light is concentrated on the 8mm size gate. The EJL has a bigger filament to cover 16mm. 2, I think the genuine ESC is slightly over run. This would explain the 25 hrs expectation where as the EJL is given an average 50 hrs.
Now if the EJL was overrun slightly which would result in an increased light output I wonder how much extra light you would get.
There is a possibility to overrun the lamp slightlt but I will do some tests before I give my thoughts on actually doing this.

Kev.

Posted by Mark Norton (Member # 165) on September 22, 2005, 02:32 PM:

Great Kev, sounds like a bright idea over-running the EJL slightly. Even if the lamp life is greatly reduced, not a problem due to the low cost and the low setting can always be used for economy of lamp life. Be interesting to hear you thoughts.

Posted by Paul Adsett (Member # 25) on September 22, 2005, 06:39 PM:

Kev,
am I right in thinking that the way to overrun the lamp a little bit would be to move the transformer tapping to the next lower setting? Can this be safely done without any danger to the transformer and projector electronics?

Posted by Tim Christian (Member # 48) on September 23, 2005, 12:57 PM:

It is hardly worth the candle. Typically, an increase in lamp voltage of 10% will only hike colour temperature by 3% (say 100 K) but will reduce lamp life by 2/3 from about 50 h to 17 h.

Posted by Kevin Faulkner (Member # 6) on September 25, 2005, 09:16 AM:

Paul, That is one way to do it. I am going to have a look at this by using a Lux meter to tkae measurements. There is another way to achieve an extra volt or so and I am looking into this as well.
All the low voltage areas of the Elmo are well protected by regulators etc so a drop down on the transformer shouldnt be a problem. Do so at you own risk!!!

Kev.

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