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Help! Quick question for Preston owners


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#1 Ed Moore

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Posted 19 June 2009 - 01:53 PM

Hi all,

Shooting on Tuesday on an F900 and production has rented a Preston (despite the best effort of my ACs, I haven't yet sold a kidney for my own).

Just triple checking I can power the receiver properly - ideally we want to power it from the camera as there's much switching from handheld to steadi to be done and the AC and I want to keep the rig together.

Are we going to have any problem powering the Preston receiver from the D-tap socket on the F900? Not the one on the battery plate (I'll power the camera off the rig), but the one usually used for a camera top light. I know there's a switch controlling that outlet that sets whether it's on continously or 'auto' - just on when the camera's running, but presuming I set that right (!) is it going to be okay?

The AC mentioned something about the Preston liking 24V, but surely it's just as happy with 12V?

Many thanks, Preston-savvy dudes.

E
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#2 Alfeo Dixon SOC

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Posted 19 June 2009 - 02:49 PM

The AC mentioned something about the Preston liking 24V, but surely it's just as happy with 12V?

Hey Ed,

If your giving the MDR2 12Volts it should work, now I'm not sure about how many Amps it requires and what the output of the socket is. But no problem with 12V supply. Not sure about the MDR1

-Alfeo
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#3 JobScholtze

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Posted 20 June 2009 - 05:59 AM

The AC mentioned something about the Preston liking 24V, but surely it's just as happy with 12V?

Hey Ed,

If your giving the MDR2 12Volts it should work, now I'm not sure about how many Amps it requires and what the output of the socket is. But no problem with 12V supply. Not sure about the MDR1

-Alfeo

i believe it wont work. When the motors are turning, the use more amps then that Dtap can handle. I know that it wont work with the bartech, so i guess it wont work with the preston.

Perhaps ypu could bring 2 cables with you. One with D-tap for the handheld/stick work. ( powering from the battery plate that is) And one powering from your rig.


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#4 Brad Hruboska

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Posted 20 June 2009 - 09:24 AM

[Funny enough I have found the preston to be more power tolerant than the Bartech, i've even had jobs where the preston warning light flashed all day and we still had perfect control. Try using a d tap straight to the battery, usuelaly there is one or two p- taps on the mount, or see if the rental house has a 4 pin XLR to P tap adapter.

I got kind of frustrated and made a sled power to p tap and XLR adapter box for my rig to alleviate these 'where do i plug this in ?'questions...

BH
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#5 Alfeo Dixon SOC

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Posted 20 June 2009 - 09:54 AM

I'm not sure about how many Amps it requires and what the output of the socket is.


12 volts @ 50 Watts which is 4.2 Amps and the MDR2 works as low as 11 Volts drawing only 46.2 Watts needed

....it is W = V x A right?!?

-Alfeo "the dyslexic" Dixon
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#6 Ed Moore

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Posted 20 June 2009 - 10:09 AM

Thanks all for your advice. I'm trying to avoid needing to use the P-tap on the camera's battery mount as that only works with a battery on the back and I need to get as much weight at the bottom of the sled as possible.

The rental house has put in a Preston > XLR4, so for this one I think I'm just going to parallel a spare XLR4 female into my sled>XLR4 cable so the one cable can run the camera and the preston.
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#7 Jess Haas SOC

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Posted 20 June 2009 - 05:23 PM

See if the rental house has an XLR to AB plate. It allows you to power the camera from XLR while still being able to use the p-tap.

~Jess
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#8 Alec Jarnagin SOC

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Posted 22 June 2009 - 06:08 PM

Pretty sure you are fine powering an MDR off the A/B tap (I have the cable - bought from Preston, so one would hope.... can't remember if I've ever used it).

Also, considering the number of A/B power tap AKS that are out there now, I highly recommend everyone carry with them cables from their junction box to reverse A/B tap (i.e. an adapter cable to adapt any power tap cable to your J-Box).
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#9 Ed Moore

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Posted 22 June 2009 - 08:15 PM

Hi all,

Update - MDR2 with one DM2 attached for focus is quite happy running off camera handle P-tap on F900 series. If I get a chance I'll try it with the other two motors as well.
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#10 Alfeo Dixon SOC

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Posted 22 June 2009 - 09:57 PM

Hi all,

Update - MDR2 with one DM2 attached for focus is quite happy running off camera handle P-tap on F900 series. If I get a chance I'll try it with the other two motors as well.

Ed,

Good to hear it. Just happen to be talking to James over at Preston today and he said the most it should spike is about 1amp per motor when the motors reach the end stops during calibrating (which is hardly ever at the same time.) So if you can calibrate, you will be ok.

-Alfeo
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