David, you wrote,
> I recently purchased a Sound Device 702. I would like to record at times =
up to 18 hour running 2 mics using phantom. I understand the 702 can be pow=
ered by an external battery using the Hirose connection.
> I=92m sure it=92s possible to make a cable but is there a commercial cab=
le available to connect to a suitable battery?
>From Sound Devices, the XL-H4 cable powers the recorder from a 4-pin XLR. T=
hat would allow you to power from a motion picture industry battery belt or=
other large 12V (nominal) battery.
> What size battery is needed? Does the battery need to power the recorder =
at 7.2v (as the power pack) or 12v ( as alternate power supply at home- 240=
v). My understanding is the Hirose connector has 4 pins. 2 powers the unit,=
the other 2 supply power to power pack. Having all 4 pins wired would powe=
r both recorder and power pack, requiring 12v. Wiring to correct 2 pins jus=
t to run the recorder requires 7.2v.
> Any advise would much be appreciated.
The Hirose will accept 10 to 14 volts.
18 hours is a challenge. I record or stand by with my 788 all night. First =
I reduce power use by removing the hard drive. That=92s because on the 788 =
you can=92t turn the drive off. 702 doesn=92t have one.
I use the accessory XL-NPH to power the recorder from IDX NP-L7S batteries.=
I go till I get a low-voltage warning in the headphones, then pull the bat=
tery stick and replace it with the next one. The L-mount battery on the bac=
k of the recorder bridges the battery change with no problem.
On a recent session recording with six phantom-powered MKH mics the first b=
attery, my oldest one, lasted 4.5 hours, the second (and second oldest) gav=
e me 5 hours, and the third took me through the end of my 12-hour session w=
ith power to spare. YMMV, it depends a lot on battery age and the time sinc=
e charging=97older batteries seem to droop faster in full-charge storage.
-Dan (Sound Devices dealer)
> Cheers
> David
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