Here is the issue- I am getting noise (high pitch static whining) when using multiple Rodelink receivers powered by a USB power bank.

The details:

Tired of running everything in my field audio kit off AA batteries, I decided to invest in a couple of USB power bricks to run everything in my audio bag. Specifically, this is powering a Sound Excellence ENG 44a mixer, two Rodelink receivers, and a Tascam DR-05 recorder.

When powering everything off AA batteries all is good. However, once I try to run everything off USB power I get a high pitch noisy hum from the channels the Rodelink receivers are on.

While troubleshooting I discovered the following-

a) If I run only a single Rodelink receiver off of a USB power pack with all other items connected to another power pack, there is no noise from that receiver.

b) If both receivers are connected to the same power pack, with nothing else connected, I will get noise. However, this noise vanishes if both inputs are set to the same level on the mixer. The noise gets louder as the difference in their levels grows greater. Each receiver by itself will produce no noise when the other receiver is disconnected from the USB power.

c) Connecting one or both of the receivers to the USB power pack along with the mixer will always produce noise.

d) Connecting the Tascam recorder to USB power along with one of the receivers does not produce any noise.

e) Swapping USB power cables, audio cables, and different USB power packs has not made any difference.

If anyone has any suggestions, please let me know :)

Sounds like some kind of grounding problem, is this it ...

RodeLink Filmmaker Kit Interference Solution - YouTube

If it is follow Ross’s advice and also, email the problem to your local Rode agent or Rode in Sydney.

You might need to fwd. the model, serial numbers and the date you bought it .. of all your gear.

Cheers.

Unfortunately, my issue is not the same as what is depicted in the video. The issue I am having is present even when the transmitters are turned off, and it is only present when the receivers are connected to a USB power source in the specific configurations described in my original post.

Trying to help you, try option 2.

Email Rode in Sydney direct, that’s where their agents will fwd your problem ...

https://en.rode.com/contact

Cheers.

Poor regulation when the power bank has to supply increased current - they have to multiply up voltage to enable charging from 5V supplies, so could simply be the power supply oscillating and then poor or no harmonic suppression - don't treat them as a battery supply, but as you would a computer type power supply - and we know how horrible many of these can be audio wise.

Sounds like your power supply is sufficient to operate a single receiver. But it is too wimpy to operate more than one receiver.