$150 for a 575 HMI par?

Yeah it's been raining a lot here and I have some editing deadlines to meet but I want to do a test at night as well. I asked for a bulb and they charged me 10 for one. I ended up paying like 290 bucks in the end but I got barn doors, gel filter, and a adapter for the yoke to fit on light stands and shipping. The ballast fan does make some noise that could be an issue indoors but outdoors it would be fine with all the other ambient noise you will be fighting. I'll try and do an audio test when I get the chance.

over all I like it but the fan is what might keep me from buying a second one for now (plus I'm looking at the fiilex LEDs or possibly upgrading to the C100 so I need to budget accordingly)
 
Thanks for all the info guys, I did end up ordering one and after some work got them to include a used globe. I went for the TMB Power Par as well. I figure worst case it'll be handy for punching through windows and best case I'll find a way to minimize the fan noise either by disabling or replacing the fan and use it closer to talent. Hopefully it'll help me stop having to rent Joker 800s on jobs. I'll let you know how my testing of the unit goes after it arrives.
 
I just received my TMB Power Par and it all looks quite good, very bright for the price and I like that it's actually quite compact for a 575W HMI Par and that the ballast isn't another piece I have to separate and pack. Took a minute to figure out how the lenses go in, and it could really use a system for rotating the lenses given the elliptical beam. I did a very quick preliminary shutter speed test and it looks good up to 1/250th sec shutter which is pretty good and probably all I'll need 90% of the time. Flicker seems fairly faint past there but it gets progressively worse as I increase shutter speed. I will test this with other cameras to confirm, though.

The fan is definitely a fairly offensive sound but there does only appear to be one fan so I plan to do some tests to see if it operates without the fan running and will probably try to pull out the fan and see if it can be replaced with a larger/quieter fan.

I guess this is a theatrical/exhibition light so it's sort of expected it has no switch though that seems surprising to me with an HMI since I'm used to ballasts with more feedback about whether the head is connected and ready to strike etc, but it seems pretty responsive to disconnecting and reconnecting power so I'll probably just use it with a power cord that has an inline switch.

I'll check the photometrics and color when I get a chance, though I probably won't have a chance till next week.
 
Let us know how the science experiment with the fan goes. I'd be interested in what you get out of it because I don't know enough about that stuff to play around with it myself. Still a great light for sure and yeah I forgot to mention there was no power switch. I also noticed with the barn doors on you can only tilt the light down so far before it bumps into the ballast.
 
So far I opened the ballast and it looks like this should be a pretty easy mod. Unfortunately there really is only room for a 60mm fan unless I start cutting the ballast chassis up but I want to try the simplest solution first. First off, the main ballast component does have a warning on it that says it requires forced air cooling so a fan is probably necessary, but it's not totally clear how much airflow is necessary but using a new fan with much less noise and slightly less airflow should work. I looked up the manual on that part that requires forced air and it does say that if the fan stops working or the unit overheats it will automatically shut off to cool down, so it should be protected and I'll just have to run tests after installing the low-flow fan to make sure it doesn't shut off after running for a while. The fan in the ballast chassis is a 24v 4100rpm fan:

http://www.ebmpapst.com/en/products...fans/axial_compact_fans_detail.php?pID=53806#

So running it without a fan is probably not an option, nor is using a bigger fan (bigger fans are naturally exponentially quieter for a given airflow since they can run at lower rpm to push the same amount of air as a small fan)

I figure there are a couple factors contributing to the noise, the fan design, the fan age, and the vibration isolation.

First I considered just undervolting the fan, but it's a mechanical component in a used light so it's pretty likely that it's not performing at its best since any imbalance, dirt, wear can cause more noise. So I decided I ought to buy a new fan that's designed to be quiet, but 12v fans are much more common since there is a big market for computer case fans but the ballast's internal power output is for a 24v fan. It's possible a lot of the quiet 12v fans are just 24v fans undervolted to run at lower rpm, but I figured it's still better to just buy a new fan that has no wear and is designed to be as quiet as possible so I ordered a Silenx 60mm 12v fan that is supposed to be one of the quietest fans available. I bought a zener diode I'll just run in series with reverse bias to drop the 24v power down to 12v for the fan (I'm a bit rusty on my electrical engineering so I had to look this up). I thought about using a potentiometer so I could tweak the voltage to the perfect level but decided against it for simplicity, though I may consider using a pot or resistor to drop the voltage more if the new fan is still a bit too loud at 12v.

According to the specs, the current fan says it has an airflow of 35sqm/h which is only 20cfm and produces 28dBA of noise at 4100rpm, and the fan I ordered says it does 18cfm and is only 16dBA at 2000rpm, so it should be a big improvement if specs are to be trusted.

As for vibration isolation, the fan was literally just zip-tied into the tray in the ballast and pushed up against some pretty firm, thin foam clearly supposed to dampen vibration a little. I may still zip-tie the fan back in since its the easiest mounting option, but I'll probably put some softer foam around the fan to really isolate it from the place where it makes contact with the metal tray and where it makes contact with the zip-tie. Unfortunately there really isn't much room for extra padding to dampen vibrations so I'll see what's possible once I put the component tray back into the ballast case.

Anyway I just got the fan in the mail today so I won't have time to install it until Monday but I'll let you know how it goes. I think the ideal mod might be to just cut a hole in the bottom of the ballast for a bigger fan since big fans can easily be super quiet and have plenty of airflow, but hopefully I can get away with just this new fan.
 
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So far so good, i had it running for an hour with the new fan which is whisper quiet. Now the fan is quieter than the buzz of the ballast electronics. The fan does appear to be somewhat lower speed and lower flow than expected but it's super quiet. I did test the voltage drop across the 12v diode but didn't test it across the fan, but the diode did read 12v so the fan should be getting the remaining 12v. I can feel the hot air coming out of the vent on the opposite side of the fan, so there is definitely some airflow moving hot air out of the ballast. Hopefully the airflow is enough, but I imagine if the unit is designed to turn off when it senses overheating and it didn't overheat or turn off after an hour of use that is a good sign. I guess the real test would be in a hotter environment where maybe the airflow will not be high enough.

I also added some foam on both sides of the fan to isolate any vibrations a bit better, which made the fit a bit tight when sliding the tray back into the ballast, and in retrospect the foam is probably unnecessary since the fan is so quiet and the rpm's are so slow that it's hard to imagine it causing too much noise from vibration. But any isolation helps so I might as well leave it in.

Now I guess I should move on to testing the particular color balance of the bulb they gave me. I imagine the bulbs may vary a bit from one to another and may change over time.

I wonder if I can even tell the age of the bulb by the color temperature shift.

It's pretty awesome to have a compact 575W HMI par for only $200...
And even as a used unit it's probably way better than a $1k chinese knockoff 575 hmi (usually fresnels so lower output, too) since those are likely to fail early on but these used ones have been tested probably for years of use already by the previous owner. It's amazing that an Arri/mole version of this light is $5K+! Granted of course the $5K+ version is hot restrike (using the $250 bulb) and has a remote ballast and a much more convenient lens changing system. Frankly I might just leave the VNSP lens in and diffuse it if I need a broader beam angle. Then again the heat from the beam on the spot lens might be too much for a regular gel...

Now to find barn doors that work with this unit since I didn't buy them from the vendor. Anyone know where to get cheap ones?
 
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The MTB Flexipar barn doors should be an exact fit - Amazon had them for $28 or so - or any Source Four par doors should work. (Altman also knocked off that fixture, as did a lot of DJ lighting type manufacturers). Barn doors are handy to keep gels from fading - they also made a gel-life-extender thing, sort of like a snoot or top hat, slides into the accessory slot.

Lens changes are actually easy with the $10 lens tool, but you'll have to do some googling to find it (here's one for five bucks). A paint can opener (free at any paint store) also works well.

I didn't realize the lenses go in "concave" for some time (the lens bows inward towards the globe). That made things a little easier, but "the F word" can be handy when changing those things!

Awesome news about the fan, too.
 
Michael Carter said:
The MTB Flexipar barn doors should be an exact fit - Amazon had them for $28 or so - or any Source Four par doors should work. (Altman also knocked off that fixture, as did a lot of DJ lighting type manufacturers). Barn doors are handy to keep gels from fading - they also made a gel-life-extender thing, sort of like a snoot or top hat, slides into the accessory slot.

Lens changes are actually easy with the $10 lens tool, but you'll have to do some googling to find it (here's one for five bucks). A paint can opener (free at any paint store) also works well.

I didn't realize the lenses go in "concave" for some time (the lens bows inward towards the globe). That made things a little easier, but "the F word" can be handy when changing those things!

Awesome news about the fan, too.
Click to expand...

Thanks for pointing me in that direction with the barn doors, I ordered a set. I may even order another one of these HMIs since I have a rolling light kit that would be perfect for holding two of these units. And with the fan mod there's no reason not to. I wonder if there's a way to even lessen the hum from the head now that that is the loudest sound...

Still working on proper gelling to leave in the filter tray. I tried the 1/2 CTO and 1/4 minus green combo you mentioned in the first post, but it came out too orange. It does seem that 1/4 minus green is right but I think 1/4 CTO might be more appropriate as wel. I have been evaluating color temp using my A7S and shooting RAW and testing in ACR which I suppose should get me in the ballpark. The 1/2 CTO got me to 4500K so I think 1/4 should be just right. According to the mired shift calculator I was using, 1/4 made more sense but then I thought the 1/2 might be necessary because of an added shift from the minus green but it didn't seem to be the case. Maybe it depends on the minus green?

One nice thing is I can always pull out the filter tray and probably get a pretty nice unfiltered blue-green moonlight effect, and that's usually where you really need the most punch, in a night ext...
 
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I find the gel combos for daylight stuff is just trial and error. I get a lot of info with a raw still, opening it in camera raw, and playing with the sliders while eyedroppering a gray. I guess I've gotten good at looking at the tint and WB sliders and guessing the gels (Wb slider is CTP/CTB, and tint slider is minus or plus green) - gel the fixture, rinse, repeat. And then write it with a sharpie or something on the fixture!

I imagine the various affordable entertainment lamps may have some variance, too - they're probably just designed to be "really bright and blue" vs. some specific temp.
 
Well I just ordered another light yesterday and it arrived today. It even came with barn doors! Of course I also ordered two sets of barn doors from Amazon yesterday too so I'll have an extra set... But the second set got me free shipping so it didn't cost that much.

I did pull out the bulb to confirm what kind it came with and it is a Philips msr575/2. Oddly these are sometimes listed as 80 cri and sometimes as 70 cri. I guess I can just hope I got the 80 (+?) cri ones and test thoroughly. Or maybe 70cri is an old spec. So far they don't look offensive in my tests gelled with 1/4 cto+1/4minusgreen. Frankly I always take cri with a grain of salt since most often low cri comes from rendering one color particularly poorly but most colors pretty accurately. Interestingly the spectral graphs listed for their 575/2 cold restrike (70 or 80cri) and 575 hot restrike (95cri) bulbs is identical only with a different scale for some reason. I wonder which bulb the graph is correct for or if maybe it's neither or they are actually the same and they just pretend the cold restrike bulbs have lower cri to keep sales of the hot restrike bulbs up...

It is pretty nice that you can just take out one bolt and remove the bulb without messing with the lens/mesh/filtertray/barndoors.
 
Yeah, CRI is fairly meaningless vs. "can I gel it to look fine?"...

Man, my fixture, you remove 3 screws for the lamp casing, then you take a wrench and loosen the strain relief, slide the cable in as you pull the housing up and the strain relief parts fall out… sheesh.

It's interesting to take a raw shot of a gray card and look at the RGB histogram in Camera Raw, too. Gives you a good idea of color spikes.
 
Ok well those barndoors from amazon don't fit, they are oddly 7.75" instead of 7.5" so I may just take a metal file to them... They also only sent me one set which it turns out is all I needed but it is very odd since I ordered and paid for two sets!

Edit: actually it looks like they shipped each barndoor set separately so the second set that I no longer need and doesn't fit anyway is arriving tomorrow :P

Michael Carter said:
It's interesting to take a raw shot of a gray card and look at the RGB histogram in Camera Raw, too. Gives you a good idea of color spikes.
Click to expand...

How so? Color spikes or do you just mean the general color cast? Problem is pointing a light at white/grey doesn't really tell you what it'll do once you point it at some colorful object whose color it is very deficient in. Frankly cameras have a lot of trouble nailing certain colors anyway so as long as skin tones are fine, I usually don't worry too much about a rendering a particular color right. When it comes down to it, if you need a saturated color to be correctly portrayed usually you have to do it in the color grade on a calibrated monitor.
 
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Really no lenses? Yeah the yoke adapter you just have to get elsewhere but those are like $10. You ordered the tmb power pars? How much did you pay? Only the bulb and barn doors should be extra but I was able to get both without paying extra. Though the barn doors may have been an accidental addition to my second light. I bet you could complain about no lenses. Did you talk to a rep? I just had to talk to someone over email for a while to get them to include bulbs on both my lights.

If you buy lenses separately, I wonder if any normal source 4 par lenses should work, they aren't too expensive but a believe are very necessary for avoiding dangerous UV radiation. I probably won't use half my lenses and might just leave the medium lenses in and diffuse when I want a wider beam. . The vnsp and nsp are almost identical so I don't think I'd ever use the nsp lens.

Just used them on a job yesterday on location and they worked great. Turns out they fit perfectly as a two light kit in a case I already had so they are a great addition to my kit. Now I just need a couple heavier duty stands for them...
 
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