Help with Source Fours

[Catwalker]

At the school where I work, about 2/3rds of the ellipsoidals we have are Strand SL 575 watt fixtures. The other third is Source Four 750 watt. The Source Fours have a much higher wattage, yet the Strands are way brighter. Can somebody tell me why?


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[chausman]

Have the S4s been bench focused?

 

[Catwalker]

No, we have been on a string of one show after another for a long time. I'll have to try that.


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[Brandofhawk]

Have you checked the lamps in the Source 4's to make sure that they are indeed 750 watt lamps?
Are the throw distances the same for both kinds?
Are the degrees the same?

From the manufacturers data sheets:
Strand 26 deg with 575w GLC - at 30' = 13.9' Beam and 216 fc.
Source 4 26 deg with 750w HPL - at 30' = 13.4' Beam and 196 fc

As we can see the Strand unit produces a larger beam and 20 more foot candles.

Strand 26 with 575w GLC at 45' = 20.8' beam and 96 fc
Source 4 26 with the 750w HPL at 45' = 20.1' beam and 87 fc

Here note that the difference is smaller than before, but there is still a difference of 9 fc.


I'm actually surprised here, I figured that the Source 4 should be brighter butthey simply are not.
It appears that the Strand unit is just not as good as the Source 4 at throwing long distances.
It is probably something to do with the actual lamps and design of the fixtures.
You can try benching them properly to get the most light out of the fixture.

Edit: If it is really a concern you can try buying some GLA lamps - these are the long life version of the lamps used in the strand units. Like the long life lamp for the source 4, they produce less lumens so they will ultimately be darker on stage. I'm not sure on the calculations needed to see how much less however.

 

[Repeater]

At the school where I work, about 2/3rds of the ellipsoidals we have are Strand SL 575 watt fixtures. The other third is Source Four 750 watt. The Source Fours have a much higher wattage, yet the Strands are way brighter. Can somebody tell me why?

*************

Are there really 750 watt lamps in them, or are you assuming there is because it says 750 on the outside of the fixtures? The 750 merely means that the fixture is approved to use a 750 watt lamp. They COULD have a 375 watt lamp installed!

Or, they could have 575 or 750 watt Long Life lamps in them, which automatically means that they will be dimmer than the ~300 hour-rated lamps that are available.

-Laryn

 

[techieman33]

I really like my sl's when they work, never done a side by side comparison though. The problem with the sl is they aren't as durable as a source 4, and replacement parts can be very hard to get.

 

[jglodeklights]

SL's are actually pretty good. However, you can't get parts for them, easily, anymore, and if the lamp isn't of good quality you can't get it centered/trimmed properly while keeping it from bouncing all over the place. I like them. Others think I'm crazy.

 

[techieman33]

SL's are actually pretty good. However, you can't get parts for them, easily, anymore, and if the lamp isn't of good quality you can't get it centered/trimmed properly while keeping it from bouncing all over the place. I like them. Others think I'm crazy.

Well duh, ETC didn't make it so it has to be crap. At least that's what the majority of people will tell you, even though they've never been exposed to anything else.

 

[lightman02]

Well duh, ETC didn't make it so it has to be crap. At least that's what the majority of people will tell you, even though they've never been exposed to anything else.

I couldn't agree with you more on that!! I like ETC's stuff as much as everyone else, it functions well and sure does look pretty but there are plenty of great companies out there not just ETC, even the small ones that make a good product.

 

[len]

Have you checked the lamps in the Source 4's to make sure that they are indeed 750 watt lamps?
Are the throw distances the same for both kinds?
Are the degrees the same?

First thing I thot, too. Compare apples to apples.

 

[TheaterEd]

Have you checked the lamps in the Source 4's to make sure that they are indeed 750 watt lamps?
Are the throw distances the same for both kinds?
Are the degrees the same?

When I took over my auditorium I found that I had a full array of s4 fixtures that had not been bench focused and are using 575 watt lamps. Make sure you bench focus and check the wattage.

 

[Catwalker]

First thing I thot, too. Compare apples to apples.

I am comparing the 19 degree versions of both fixtures.

And, thanks to everyone who responded.

 

[Catwalker]

Just a results post-I found EHG lamps in them, and after I put a HPL in one, and gave it a good bench focus, they worked even better than the Strands at long distances!


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[gafftapegreenia]

Just a results post-I found EHG lamps in them, and after I put a HPL in one, and gave it a good bench focus, they worked even better than the Strands at long distances!


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Well, shoot, there's yer problem!

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[Scenemaster60]

I should say! I have a limited working knowledge of the SL lantern, but in my experience I have always LOVED its optics. That's where my admiration ends. In my opinion it is superior to the S4 in terms of optical performance. That said, it has many drawbacks which is what killed it commercially.

If you take care of them properly and keep a stash of the essential spare parts (especially those damned black plastic rotation glide thingies) you have a very fine instrument on hand. I would never give up on an SL until I couldn't find the parts, especially for gobo projections and other detail work.

The bitter reality is that you are going to retire these instruments one by one as they fail and you cannot find the parts or the expertise to repair them. It was a brilliant, but ultimately flawed design that did not survive the pressures of time OR the market.

Children's Theatre Company here in Minneapolis is currently using an inventory that consists of primarily Strand SLs. Their Master Electrician, David Horn, determined the SL to be a superior instrument optically about 10-15 years ago. On that basis he purchased well over 100 Strand SLs to replace their hopelessly outdated Kliegl 1355 inventory (some of which I personally now own, head bow in shame.) They are still operating on their SLs, but I do know that he regularly makes parts grabs whenever the opportunity comes up.