anderson07 Posted December 18, 2014 Report Share Posted December 18, 2014 Hi everybody, I'm new to the group (this is my first time posting.) I've searched for answers to this but didn't see anything on this specific topic, so here I am At this point, I'm using Sennheiser G3s for my wireless. I was hoping to run them from my bags power distro (Remote Audio BDSv4, with NP-L7 batteries) so I bought Sennheisers DC2 power adapters and Remote Audio BDSCPT output cables. Now, I wired up one of my wires, but every time I've used it I've gotten low level background hum. I've heard that this is a common problem with these adapters, has anyone else here had this problem? And if so, how did you fix it? I'm open to any ideas! Quote Link to comment Share on other sites More sharing options...
chrismedr Posted December 18, 2014 Report Share Posted December 18, 2014 never used an unit like this, but when looking it it up i stumbled about this: http://www.remoteaudio.com/bds_v4/ Noise and shared power systems Thousands of satisfied field audio professionals are using the BDS system to power their equipment. However, it is possible to have unwanted audible noise induced into audio systems by a common (shared) power source. To optimize your system, it is recommended to use line level signals instead of mic level signals whenever practical. Also, turn phantom voltage off of all preamp inputs that are connected to non-microphone devices. If noise is still heard, unplug one device at a time from the BDS box to determine the cause. Notice any change in noise associated with the removal of each device. If the noise goes away after unplugging a particular device, try powering that device with a separate battery. If using a separate battery causes the noise to go away, then the problem is a ground loop associated with the combination of a common power source and audio grounding schemes. Be aware that this noise will not be removed with “LC” filters found in some distribution boxes. Here are four options for removing such noise by interrupting the ground loop: use a separate battery for the offending device; try different grounding/floating schemes with the audio cables; in devices that use a single 9V battery, use an isolating 9V battery eliminator such as made by Lectrosonics; use a power isolator cable such as the Remote Audio Juicer cable. Quote Link to comment Share on other sites More sharing options...
DanieldH Posted December 18, 2014 Report Share Posted December 18, 2014 I've had a similar effect when feeding some EK 100 G3 from the same Hawkwoods Vmount plate as a 788t. (Though it was more LF irregular garbage than a constant hum). My quick&dirty solution was not to feed the 788t from the plate, but instead use the batteries build in DTap to power the 788t. Edit: After all, the DC2 cables isolation layer wore off. (poor design?) and I went back to AA batteries. Quote Link to comment Share on other sites More sharing options...
Ryan Coomer Posted December 18, 2014 Report Share Posted December 18, 2014 This is normal when using the Sennheiser Battery eliminators with a BDS - there is no built in isolation. In the past, our service department has installed inline dc/dc isolators to correct this. They found a fairly small solution, that is about 1" x 3/4" x 1/2" and works really well. Quote Link to comment Share on other sites More sharing options...
Matt Morris Posted December 18, 2014 Report Share Posted December 18, 2014 I've done the same, and as Ryan said, I installed an isolating DC to DC converter in my homemade BDS. Check out the XP Power JCA1012S12. You could just fit it into a small box and wire in series with the batt eliminator. Quote Link to comment Share on other sites More sharing options...
nourZX Posted December 20, 2014 Report Share Posted December 20, 2014 I use this battery , i cut the dc out and replace it with d-tap It have a regulated 12v out , with a d-tap splitter it can keep 4 lectro 400 series running for 8 hours. Plus its very cheap and fast to charge! Aibocn BP-U60 BPU60 Rechargeable Replacement Battery for Sony PMW-EX1 PMW-EX3(14.4V 6600mAh) https://www.amazon.com/dp/B00DI2DZU4/ref=cm_sw_r_awd_NquLub1BESYSP Quote Link to comment Share on other sites More sharing options...
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