HPL Lamps

[Stoldal]

Now that i am going to be working mainly with HPL lamps. I have a question. Is the only difference between 575/115X and 575/120X the voltage? I just don't want to miss something important.

Thanks

Matt S

[derekleffew]

I've had the same question. There has to be a difference between
ETC Part#RT114 HPL 575/115X (Ushio Specs) Other
and
ETC Part#RT171 HPL 575/120X (Ushio Specs) Other
right?

ship? STEVETERRY?

[Sean]

Originally Posted by derekleffew

I've had the same question. There has to be a difference between
ETC Part#RT114 HPL 575/115X (Ushio Specs) Other
and
ETC Part#RT171 HPL 575/120X (Ushio Specs) Other
right?
ship? STEVETERRY?

Yes, it's the voltage they're rated for, 115v vs 120v.

The voltage drop after the SCR in the dimmer, and the cable run to the lights in a theatre is often ~115v. However, if you just plug the lights straight into the wall, then you are more likely to see 120v. Not having them all match will mean a bit of variation of color temp. Using a 115v lamp in a 120v circuit will mean (slightly) reduced lamp life.

The "x" means they're the extended life--an option....at the cost of intensity and color temperature.

--Sean

[zac850]

My theater electrics teacher has a story of when he brought some tour into one of the big theaters in Washington DC. Apparently for whatever reason, their voltage is usually around 126v at the circuits. He plugged in his rig, turned it on, and everything got very bright, and then rather dark.

That theater has a large stock of 120v lamps for this reason, if you run 115v lamps at 126v their life expectancy plummets.

In most theaters I work at, I get around 117-114v at the circuits, which is why the 115v lamps are most common.

[icewolf08]

Originally Posted by Mstoldal

Now that i am going to be working mainly with HPL lamps. I have a question. Is the only difference between 575/115X and 575/120X the voltage? I just don't want to miss something important.
Thanks
Matt S

Originally Posted by derekleffew

I've had the same question. There has to be a difference between
ETC Part#RT114 HPL 575/115X (Ushio Specs) Other
and
ETC Part#RT171 HPL 575/120X (Ushio Specs) Other
right?
ship? STEVETERRY?

Why does there HAVE to be a difference other than the obvious? You are looking at the difference right in the description of the lamp. They engineered the lamps to have peak performance at either 120V or 115V, the idea being that you match your lamps with the line voltage as Sean said. The other idea being that both lamps' peak performance will have the same output characteristics at different voltages. Though some people will buy the 120V version to put in 115V systems to eek a little bit more life out of them.

As also mentioned, the biggest thing to pay attention to in the HPL lamp land is the standard vs. X types, as the X types are long life, and if you look at the specs, a 750X has almost the same lumen output as the 575 (non X).

[SerraAva]

An HPL 750w X is actually dimmer then a HPL 575w by a 120 lumen's. The 750w 115v has 5 times the lamp life and the 120v nearly 7 times the lamp life however. Here is a basic list run down, same lumen output for 115 or 120 volts:

Standard, all color temperatures 3200K, all lamps have 300 hour lamp life:
375w: 10540 Lumen
575w: 16520 Lumen
750w: 21900 Lumen

Extended life, all color temperatures 3050K
375w: 8000 Lumen 1000 Hours
575w: 12360 Lumen 2000 Hours
750w: 16400 Lumen 1500 Hours for 115v, 2000 Hours for 120v

I myself generally run 750w 115v X in everything. Gives me punch, and lamp life too. If I really need something brighter, I keep a stock of 750w 115v standard around for when I need the extra 5500 lumen's. I have never seen a 375w HPL before, and I run in to the 575w often, they seem to be the most common.

Some food for thought. Each increase of wattage is directly proportional to the increase in lumen output(ok, it's off by a point from 575w to 750w, and 2 points in the case of 375w to 575w in favor of the lumen output though). If ETC ever made a 1000w HPL, the standard version would have a lumen output of 27375 and the extended life would be 20500 lumen.

[Stoldal]

For the the theatre i am helping put together. Should i just all HPL 575/115X or should i use a mixture of both 575/115 and 575/115X. All the fixture that we are getting are source 4s. So i am just trying to figure out what lamps should have and have on hand

[icewolf08]

Originally Posted by Mstoldal

For the the theatre i am helping put together. Should i just all HPL 575/115X or should i use a mixture of both 575/115 and 575/115X. All the fixture that we are getting are source 4s. So i am just trying to figure out what lamps should have and have on hand

That really depends on if you need the output, or if you are concerned about lamp life. The X version puts out less light at a lower color temp (more yellow), and the standard gives you more output at a higher (whiter) color temp.

[Les]

If this is school or non-profit, I would go with long life over high output.

[Stoldal]

it is Both, that is why i was think for the longer life lamps