GH4 GH4 +tascam dr70D both powered from power bank causes strange noise

Ted Ramasola

Ted Ramasola

Veteran
I posted this earlier on the location/sound threads, but after talking to someone with a tascam and a gh camera, he said he got the same issues on his GH2 and tascam dr60D so I'm posting this here in case someone has the same problems and a solution.

I got an XTpower/anker 10000 mAH power bank which has both USB and 9v out to power simultaneously my GH4 and Tascam DR70D. They both work fine.

BUT when I connect the line out of the tascam to the GH4 a warbling/pulsating sound like an out of phase device can be heard from the headphones. This can be heard from either gh4 or tascam headphone out.

The distorted pulsating sound disappears when either of the gh4 or tascam is disconnected from the power bank.

The sound is also not present if I connect the GH4 and Tascam to different powerbanks.

The sound is present only when they are connected to one power bank, but only if the line out from tascam is connected to mic in on the gh4.

Anyone has an idea whats going on?

Thanks in advance.
 
Dirty power feeds from the two power lines not being isolated from each other enough.
Probably nothing you can do about that.
I have those batteries for my Blackmagic cameras and I simultaneously power an external monitor with them and that works ok.
I use these RavPower little darlings for my DR-70d because they are even smaller, they're the perfect shape to velcro to the DR-70, they're light, they record with phantom power for about 13-hours, and ...oh yeah...I paid $16 bucks each for them!
I did a whole post here a while back on them with pictures and a battery life test.

Here it is: http://www.dvxuser.com/V6/showthrea...battery-for-Tascam-DR-70D-(Tested)&highlight=

EDIT: Just remembered you and I kicked it back and forth on that thread mate!
Whynacha get one?

More importantly though - this warbling audio you hear in the headphones - is it getting recorded that way on either or both of the devices too?
 
Last edited:
DPStewart said:
Dirty power feeds from the two power lines not being isolated from each other enough.
Probably nothing you can do about that.


More importantly though - this warbling audio you hear in the headphones - is it getting recorded that way on either or both of the devices too?
Click to expand...

You're probably right about the power not isolated. I'll just get another batt for the dr70D and just dedicate the one I have for the camera since it has a 9v out.

The "distorted sound" like some kind of pulsating/electrical interference is recorded.

When the cable from tascam to gh4 [mic in] is removed and I start recording on the gh4, then I plug it in, no distortion/interference is audible, upon stop of recording, the distortion comes in.

Distortion is present upon power on of both devices when mic in cable is connected.

Glad you posted your test result, that will help me in calculating how much Amh power I need for the tascam battery.
 
Well...looks like that battery I got a bunch of was on some extended super-sale...because now it's back up to $39.
Hmm...I never even knew that was it's original price. I bought 4 of them over a three month period.
Still a great battery for the DR-7.0D
 
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