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Those low-cost HMI PARs


Phil Rhodes

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Hello!

About eighteen months ago we had a lively discussion about some 575W HMI PARs that were being sold off at startlingly low prices by the events industry, which has largely gone to LEDs. Their LEDs do not generally have sufficiently good colour quality for film and TV work, but an HMI is an HMI. Most of them were being sold off in the USA and weren't worth shipping, but recently I noticed that AC Entertainment had one for sale ex-demo here for £100.

So, in the spirit of experimentation, I bought it.

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This is, we should be clear, not one of the Arri knockoffs being sold on eBay, a possibility which seemed to be of concern when this came up before. This is, in full, a Chroma-Q Daylight PAR. Chroma-Q is very much a bona-fide outfit which I last saw exhibited by AC at the BSC show. The company's product page for the Daylight PAR describes it as "designed primarily for tradeshow use" which explains the built-in ballast module.

The construction is based around a real, actual ETC Source Four PAR.

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AC's shipping people could have been more careful.

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Still, this gave me the opportunity to replace that bulb with a real Osram HMI.

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The three screws on the back allow the arc tube to centred in the reflector. The brown block under the G22 base is a Schiederwerk HZG 8-25 ignitor, which develops up to 25kV ignition voltage and is the reason this light can be hot-started. The company makes compatible ignitors which develop 4kV for applications where hot-restart is not required, as well as similar devices for higher wattage lights.

This leads me to suspect that the inside the box in the yoke, we'll find the accompanying EVG-5-57AC ballast module. And sure enough:

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This is also very much not a made-in-China effort; Schiederwerk is, as the name suggests, a German company. This ballast-ignitor setup is used in quality intelligent lighting such as the Martin MAC 500 and 600 among other things. Both the EVG-5-57AC and HZG 8-25 are sold as spares for more than I paid for this whole light.

This does introduce the first minor drawback: this is a square wave only ballast, without the sine wave modes which reduce acoustic noise in movie-oriented HMIs. This is often not objectionable on small HMIs like this, and can depend on the physical arrangement inside the bulb. It turns out that there is an audible 400Hz buzz when the lamp is warmed up, but really not much more than the faint singing noise that many HMIs emit if you literally attach your ear to the side of it. On the upside, this does make it flicker free, or at least as flicker-free as an Arri ballast in "flicker free" mode.

The second concern is that there is no safety interlock on the lens. Notice that I fitted a UV-shielded HMI bulb, which provides an extra layer of security here, but there is nothing stopping anyone running this thing without a lens in it. This would be a horrendous idea from the point of view of both UV shielding and explosion risk. To be fair this is a concern with every Chroma-Q Daylight PAR ever made, as well as the Enliten Exhibition PAR and the TMB Power PAR, and probably others, and they were sold by the truckload. The company clearly didn't view it as a dealbreaker and neither do I. It's professional equipment. Just don't do that.

There is a fan in the ballast which is microscopically quiet and trivially replaceable when it fails. I had considered remoting the ballast on a standard header cable, which would be a few hours work with a soldering iron and some Amphenol Ecomate connectors, but I really don't feel the need. It's not outrageously heavy. It's fine.

Beyond that, it's a 575W HMI PAR for £100, which seems worthwhile. If they had two more I'd buy 'em. Just not from AC, whose shipping department has fists of ham and fingers of butter.

P

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2 hours ago, Frank Hegyi said:

Thanks for taking the time to write that up. Cool stuff. 

I discover that if anyone in the USA wants one, PRG have a bunch in Vegas.

https://prg-proshop.com/products/item/2898/lighting/conventionals/daylight-power-par-575w

These are PRG branded but otherwise look to be identical to what I have.

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27 minutes ago, AJ Young said:

Very cool!

For the US version, I notice the plug is a twist lock on the link you shared. Is there a way to modify this light to work with edison plugs? (I'm not keen on this side of electronics)

I actually contacted PRG in Vegas to see if they were worth shipping to the UK (answer, predictably, is "hell no") and as part of that I asked about voltages. The answer from them was that they support either 120 or 208.

The voltage markings on the one in the photos are worn off, as I'm sure you noticed. The visible markings suggest they're actually identical to mine, which is marked thusly:

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Either way, you're fine. Just change the plug.

The one thing it's not proffessional at is spelling. A natural concomitant of being #16, you might think, but apparently they corrected the silkscreen before PRG bought their batch.

P

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7 minutes ago, Phil Rhodes said:

I actually contacted PRG in Vegas to see if they were worth shipping to the UK (answer, predictably, is "hell no") and as part of that I asked about voltages. The answer from them was that they support either 120 or 208.

Thank you and you're right, difficult to see on their link.

I'm curious if there is a suitable sized barn door from an old Mole/ARRI/etc that could fit.

The price is alluring, though!

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6 minutes ago, AJ Young said:

I'm curious if there is a suitable sized barn door from an old Mole/ARRI/etc that could fit.

It's a source four PAR. It'll take source four PAR barn doors, and top hats and all the different lenses, gel frames and bits and pieces that exist for them. PRG might even have some. Barn doors are of moderate use on PARs, not as good as a fresnel, but that's what PARs are like.

Although I would imagine that if you put a very dense gel in a gel frame on one of these it'd laser through it before you could say "crikey, is that a cloud of smoke."

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  • 4 months later...

I bought two of these from PRG about five years ago. I replaced the fans and the twist-locks with Edison plugs, added baby pin adapters to the yokes, and bought two new Koto 575w bulbs. They each came with barn doors but I also invested in complete lens sets for each light, as well as a speed ring and softbox for one of the lights. At the end of this modding and accessorizing, I think they came out to around $450 each.

Other than a Joker 800 and a some 1200w Desistis, I didn't have much HMI experience before buying these. I can't really comment on how they compare with dedicated cinema HMIs. However, these things have been workhorses and up until very recently, unchallenged by the newer, lower-end LED tech.

I do have a few gripes with them:

  • I find that the Koto bulbs have a magenta tint, which I correct with a 1/8 plusgreen on each light.
  • Even with the new fans, they are not the quietest fans in the world, but it hasn't been an issue when shooting interviews.
  • I really wish there was a lens somewhere between the NSP and the MFL. I think that would be the sweet spot for this output and smaller productions.
  • The head cannot to oriented straight up as the yoke doesn't offer enough clearance.
  • They head/ballast/yoke combination is around 20lb so they require c-stands.

For the price, it's a lot of light. I've found that even with the MFL lens, I get about 2/3 stop more light than an Aputure 300d ii with the reflector dish. With the NSP or VNSP, the output goes up significantly.

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