JieTu HMI

The Neutrik connector are used often in audio high output sound gear (amps and speakers). Places like Guitar Center probably carries long cables in stock.
 
Yeah those connectors are frequently called "speakon" connectors and are used for amp-to-speaker connections.

However, the Neutrik PowerCon connectors are slightly different and will not mate to a "speakon". The picture Barry posted looks like a PowerCon knockoff.
 
I'm also very interested in seeing pics of the bulb and any info printed on it.

Did they give any indication whether the 1.2k output was in tungsten equivalent or actual HID output? It says 1.2k HMI on the ebay thing but who knows..
 
Svart said:
I'm also very interested in seeing pics of the bulb and any info printed on it.
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It's a big G38 single-ended HMI bulb. Looks like this one...
http://www.bestbulbsdirect.com/Philips_MSR_1200W-2_Replacement_Jenbo_NSK1200-2

The box says MSR1200W and G38, and a whole lot of Chinese writing.

Did they give any indication whether the 1.2k output was in tungsten equivalent or actual HID output? It says 1.2k HMI on the ebay thing but who knows..
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It's a real HMI 1.2k. Tungsten equivalent would be a 5K, but that's not even a fair comparison because that 5K tungsten would be putting out orange light, and to get it blue you'd have to gel it with CTB, which means, really, you'd need a 10K to 20K tungsten fixture to match the amount of blue light this thing outputs. It's a light cannon. Indoors I needed ND3 and F4 and 200 ISO to be able to white-balance off of a white card, at 12 feet. And that was flooded out, not spotted. Is that insane or what? I mean, a 1.2k isn't that big in the world of HMI's, but in terms of something with the sensitivity of an AF100 it's like having a 6K HMI.

I am awaiting the extension cable to see if it makes it usable. If so, and if you can always hide the ballast in another room behind a closed door, then this thing becomes practical and a quite good value. If not, then ... it's only usable for MOS productions, or if you can put the light outside shining through a window or something.
 
phudsontx said:
The Neutrik connector are used often in audio high output sound gear (amps and speakers). Places like Guitar Center probably carries long cables in stock.
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Alas, only Speakon. I found a Powercon cable in stock at Markertek, but that's a few days' shipping, and I'm not entirely certain that the cabling would be wired the same. I assume it must be (I mean, what's the point of making a knockoff cable connector if the cable itself isn't compatible??)
 
The Ebay listing says 6000k.. Does it have a lot of green in it or is it fairly white/blue? A lot of the knock-off bulbs have wonky color peaks, usually in the green, for HID bulbs. The better manufacturers have more balanced outputs.
 
I tested by doing a manual white balance off my Kino Flo tubes, and then using that white balance on the HMI, and it was pretty close to spot-on. No nasty green spike.

Again, the quality of the light is not my problem with this unit, it's pretty much solely down to the noise the ballast makes. And the spotted-in look of the light seemed to add some green around the edges, I don't know if that's a lame fresnel lens or what, but when flooded out it looked pretty even and pretty good.
 
Yeah, in my experiments I've seen the green halo around some HID light before. Not sure what causes it other than some kind of prismatic effect from the fresnel. It also seems to be related to how well the doping chemicals evaporate inside the pressure chamber in the bulb and the different colored areas of light can move around.

sounds like a deal so far though.

I built a couple HID lights for experimentation and I'm thinking about an extension cord for mine( I use magnetic ballasts). The only real issue is the multi-kilovolt start pulse. The cable that can take that is a little pricey.
 
Svart said:
Yeah, in my experiments I've seen the green halo around some HID light before. Not sure what causes it other than some kind of prismatic effect from the fresnel. It also seems to be related to how well the doping chemicals evaporate inside the pressure chamber in the bulb and the different colored areas of light can move around.
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It was only on for 10 minutes or so, so yeah, maybe there's something about the bulb that would burn off over time? I just chalked it up to maybe the lens, and it's just yet another part of profiling your equipment to find what works and what to avoid...

sounds like a deal so far though.
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Jury's still out... I had a 1200w magnetic-ballast Sirio or DeSisti that I bought off ebay for about the same price... much heavier ballast, but quieter, and it just worked, but it died on me before the CMOS revolution came about and made magnetic-ballast HMIs less attractive. If this unit was magnetic, I'd have little hope for it, but because it's electronic and therefore doesn't cause the scrolling waves and bands in the footage, I have some optimism. It all depends on the power cord and whether I can get the ballast far enough away to make it actually usable.
 
Just for information's sake, you'll notice when the HID bulb heats up, it goes through a bunch of different color and brightness changes. That's the different chemicals melting and turning into plasma which changes the color temp and output. Sometimes you can get slag that sticks in the bulb and can cause dark spots too.

The color temp of the bulb can change due to fluctuations in the voltage to the bulb as well. The current to the bulb is fairly constant but the voltage can change a bit. Each bulb model is rated for a specific voltage and if you stick them on different ballasts which have different voltages but same currents, the bulb color will change as will the effective life of the bulb. This can also cause color peaks in the bulb spectral output.
 
Okay, follow-up -- I had picked up a PowerCon extension cable and a PowerCon A-B coupler from Markertek, and they just arrived today. I tried it and... yep, the connectors fit, so that connector on the HMI ballast is a generic version of the Neutrik PowerCon cable.

So -- well, just because a connector fits, doesn't mean it'll work, right? Plugged it in, and -- it came on. It worked. Son of a gun.

Which means, for a hundred bucks, you can get a fifty-foot extension cable and put the ballast way the heck out of the way and defeat the noise that way. So this thing might end up being usable after all.

Quick photometrics, at full flood it delivers a thousand footcandles at 5 feet. In fully-spotted mode, it's 4,100 fc at five feet. Not thrilled with the beam pattern when spotted in, but it's okay flooded out.
 
Cool Lights said:
On that unit, what they've done is bolt the ignitor to the side and the cord is hard wired coming out of there. You can verify it by opening up that black box on the side and seeing if there is another black box in there with 4 fairly hefty wires coming out of it. 2 are input and 2 are output. Probably different colors on each side. No polarity so its not necessary to know which side is which on input or output but of course don't mix up input and output though.

You may indeed be able to make a longer cable and put it in there yourself if the ignitor is there in the side box.

This was our 1200w cold start beta unit and a couple were bought by a dvxuser and he's mentioned them before on here. Its been about 2 years now and still running last I heard:

1200wFresnelBackViewX.jpg


About the same price. Should be using the same bulb. The longer base at the bottom is the good place to put an ignitor and we put a quick lock military connector on the outside of fresnel to be able to have a longer cord if necessary. Yoke is a professional type with our yoke clamp and the stand adapter is a junior male type.

He thought the fan on that unit was too loud but not even close to what we are talking about on this other unit in question.

I just didn't think it was worth going ahead with all these "fan" projects because I already knew what the reaction was going to be. Not worth it.
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Hey, I resemble that buyer! Yes, after almost 3 years they are still chugging along. The only complaints I have about them is the head noise is a little loud, but doesn't come up on the audio very badly, some of the screws have fallen out of the ballast/head, and the cable coating has come out of the connector some. I would love to put a better connector on the head/cable/ballast, but I am not sure that can be done.

Otherwise, pretty good units. The cold strike sucks when a grip accidentally turns off the light too soon or the genny trips, but normally after 5-10 minutes they fire right back up.

Matthew
 
Okay, last words on this ebay HMI -- the seller offers a 7-day moneyback guarantee. When I mentioned that I didn't think it was entirely suitable for motion picture production and did he know of any extension cables or what connectors it used, he offered to send me (gratis!) an extension cable. That cable just showed up. That's pretty amazing service for an ebay seller, y'know?
 
I'm just wondering, Barry, if you have had the chance to put the hmi through its paces yet? Did it deliver on set? Any other issues than the noisy ballast? I'm thinking about getting one of these soon.
 
I've only used it in testing stuff, no actual production work yet. I can't say what'll happen after it's been on for eight continuous hours or whatever, but so far it hasn't given me any reason for concern. Unless something happens to it that I can't foresee, I'd say I'm reasonably content with it. The ballast is prohibitively noisy, but with the cheap extension cable you can put it in a different room, shut the door, and not even worry about it...
 
Barry_Green said:
The ballast is prohibitively noisy, but with the cheap extension cable you can put it in a different room, shut the door, and not even worry about it...
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If thats the downside for it being cheaper and theres a simple way around it I can deal with that.
 
Barry have you used these lights on a production yet.

For the price, I'd be willing to pick one up for use where audio capture isn't a need.
 
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