Help needed with Par16's

[David A]

I think that the problem with the par16's is not the brightness, its the beam angle. They do take quite a bit of throw to get a decent size spot on them.

Rich

What?

You can get just about any beam angle you want for a PAR 16. They come in anything from 5 degrees to 50 degrees. Just get the best for your requirements.

Rich, if you've been having problems birdies being too narrow, a quick chat to your local lamp supplier is in order, mate! :)

there is little point in putting wide angle lamps in birdies with long snouts, as all the light does is light the inside of the snout, so that a 60 degree lamp will only come out as a dim 30 degrees.

[SceneMaster]

You may well have magic birdies, but in your eagerness to be belittling you are ignoring the data: PAR16s are available in beam angles from 10 degrees up, and as a front light at 1.5 meter throw, I'm sure you would agree that 10 degrees wont light up a whole person. On the other hand, a 60 degree throw will. Selecting the lamp with the correct beam angle is really quite important with all types of PAR lamp as it is the only variable you have control over.

Yeah... I admit I may have been a little harsh (sorry Rich) however it annoys me when people give clearly wrong advice which is put across so clearly as fact (if I personally don't know for sure I don't comment). I am quite aware you can get different beam angles for birdie lamps, in fact I think this was even mentioned before my post, however in the situation I rigged I don't know what the beam angle was I guess fairly wide.

there is little point in putting wide angle lamps in birdies with long snouts, as all the light does is light the inside of the snout, so that a 60 degree lamp will only come out as a dim 30 degrees.

A very good point!

[dbuckley]

there is little point in putting wide angle lamps in birdies with long snouts, as all the light does is light the inside of the snout, so that a 60 degree lamp will only come out as a dim 30 degrees.

A very good point!

Indeed, and one I hadn't twigged either, my birdies were all fitted with, well, err, random lamps! .... Hmmm... that humble pie sure tastes good

[Ekij]

Does anyone ever do the dimming of their PAR16's at 12V?

It seems a terrible waste of a 2300W dimmer to control a few 50W lamps.

A big hard powered transformer producing many amps at 12V (rectified to d.c.) supply which then feeds 12V (PWM) dimmers seems the way to go here (and it's what I intend to build for my PAR16 rig).

[Bryson]

I suspect that people do the dimming at 240v because they:

A: Already have 240v dimmers

B: Want to situate the dimmers some way from the birdies and can't afford the volt drop.

[dbuckley]

Years ago I built a starcloth dimmer, which was a 6x6 matrix, which used PWM dimming. It had a big (1 or 2 KVA, cant remember which) 24V torroidal transformer It worked very well indeed. The only thing I'd note is you need to have the PWM switching above 20KHz, so as to ensure that the thing doesnt whine through the audio system. You cant go low or the PWM beats with the mains frequency, and you get a right billious inducing starcloth...

 

Whereas PWM dimming works very well when you've only got DC, and is good for matrixing, if you have AC, it is probably unnecessary.

 

Some dimmers (eg the NJD 4 channel install dimmer) allows you to rewire it internally as a low voltage dimmer, so you dont save dimmer money, but you do save transformer money, one big rather than many small. To be honest, I would think that any decent dimmer could be rewired this way if you know what you're doing, as long as the transformer and dimmer electronics are in phase.

[SceneMaster]

To be honest, I would think that any decent dimmer could be rewired this way if you know what you're doing, as long as the transformer and dimmer electronics are in phase.

 

Then again in pro theatre you don't particularly want your 12v coming the 60-100mtr (depending on theatre size and socket location especially as a birdie is most likely to be powered from a floor dip trap). That’s a long way for 12v to go (obviously some LV signal cables are longer but there not powering anything).

[Ynot]

Then again in pro theatre you don't particularly want your 12v coming the 60-100mtr (depending on theatre size and socket location especially as a birdie is most likely to be powered from a floor dip trap). That’s a long way for 12v to go (obviously some LV signal cables are longer but there not powering anything).

Yup - 12v from a standard transformer doesn't go veryfar. I tried extending ours in January using 5amp cable, but the drop in volts even across that was enough to render asignificant difference in lumens.

[Ekij]

I was thinking more along the lines of an “intelligent birdie”. Where you ran DMX and hard power to the birdie PSU box (mounted close to or inside the birdie lantern) and it did the dimming and ran PWM to the birdie lamp. Although this requires ‘dedicated birdie dimmers’ they are going to be much less expensive than allocating a full 2300VA dimmer for a 75W birdie lamp.

 

75W at 12V is 6.25A using 1.5mm^2 cable you lose 0.6V (5%) with only an 8.5m run. So certainly it’s not practical to run 12V power for long distances.

[Tomo]

I was thinking more along the lines of an “intelligent birdie”...

Good idea that man. If only 100W PSUs were a little cheaper...