UR-RT4 / UR44 - Hi-Z noise issue

I recently bought a UR-RT4 interface an iPad 2008 9,7 inches and Cubasis last version.
I have noise issues when I plug a guitar in Hi-Z 1 or 2 input (I tried an electric fender stratocaster, an electro-acoustic Takamine TSF40C)
while the interface is plugged in the iPad with lightning - usb/lightning adapter (apple one, not a fake brand).
If I touch the interface (or the strings for the Takamine), the noise decrease a bit, so it seems to be some ground noise issue.
As I thought it was the interface, I ordered a UR-44 interface to replace the first one : the result was exactly the same ! So I felt a bit of a disappointment…
I did a lot of tests, different places, different cables, guitars, firmware update (UR44).
The sound vanishes only if I plug the interface in my desktop with usb cable : the desktop ground seems to make a difference.
I tried Thomann support and Steinberg support but they failed to help me as the UR-RT4 (or UR44) seem to work fine (almost unfortunately…).
Steinberg support thinks that it’s an app issue and they don’t support app, so here I am !
I didn’t find a lot a similar issue on the web, except this one : https://www.gearslutz.com/board/music-c … -ur44.html.

Cubasis 2.8.1
IOS 12.3.1
iPad 6ème génération 9.7"

Any idea would be much appreciated ! :wink:

Hi Nikomuse,

Thanks for your message.

Could the noise be related to the instruments in use, the input gain set too high, or the environment where you use the equipment?

For instance the regular Stratocaster pickups are known to hum in specific settings, in addition sitting in front of a computer display can result in hum as well. Another possible source could be the the power supply in your apartment/house.

Do you notice hum noise issues if you switch on Hi-Z by itself (without having a cable and instrument connected)?

In addition, what happens if you use the setup in a complete different environment (another place)?

Best wishes,

Hi Lars,

I tested in four different places to check if it could be about the power supply, and hum noise was always there.

It could be the instruments but why hum noises disappear when I plug the interface in my desktop instead of the iPad ?
Does UR interfaces need specific guitars to work without hum on iPad ?

About switch on Hi-Z by itself, I think it’s automatic on the UR-RT4, it switches when you plug a XLR or a jack (of course there is
no hum noise when I plug a mic in XLR).


Hi Nicolas,

Thanks for your feedback.

We‘ll give the topic a check Monday morning and get back to you.


Hi Nicolas,

I gave the issue a short check using this setup:

  • Yamaha BB 1024 X bass guitar
  • Steinberg UR-RT4
  • iPad Pro 12.9" 1st Gen, iOS 12.3.1
  • Cubasis 2.8.1

Having levelled the instrument properly, results in expected behaviour (near to no noise noticeable)

Changing the pickup setting on the bass, results in noise caused by the pickups.
Levelling the instrument to a distorted setting, results in noise.

Hope that helps!

Best wishes,

Hi Lars,

It helps a lot in fact ! It’s the first time I hear something relevant about this issue ! :smiley:

I’ll try some settings and when I’ll can other guitars…
It appears that recording guitars or bass on iPad can be difficult, maybe I’ll try to find a solution to put the interface to the ground, as it works on desktop…

Thanks a lot !

Best regards,


Eureka !!! After a lot of tests and research I found the solution… :smiley:
I built a USB to ground cable with an old usb cable and an old power cable with ground.
I used a USB hub to plug my built in cable and the interface and the hub to the iPad : all devices are then plugged to the ground.
No more huge hum noise with any guitar (on the fender it depends on the settings).

Now I can built a better cable. I hope this could help other people with the same issue !


Sorry for my late reply, Nicolas!
While your custom cable solution look somewhat dangerous, we’re glad to read that you’ve been able to sort out the issue yourself!


Hi Lars,

Don’t worry ! :wink:
I made a better cable which is far more less dangerous… :smiling_imp: