Hello i'm building an external ADAT-AUDIO interface and i noted the same noise witch I can hear only if no audio-signal is on a input (quit environment).
Of course I was searching the error first for a few days with me. However, when I debug the ADAT signal at the scope I could sometimes see values >> 0 on the incoming data stream.
It sounds like a old vinyl disk and you can see that also if you feed back the external DA-Converter output to a free rme Input and turn on the right DIGICheck .
I'm using also a rme a newer UFX (SW-Version 1.22 MAC OS X (1)) on a mac OS X El Capitan Version 10.11.5 2.8GHz Intel Core i5
if I disable the effect section (Reverb and Echo) then its quit !
This noise you can also measure or see on a transmitted ADAT Channel with a enabled FX-Gain)
If it helps a can send also some picture ...
AGT
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fripholm wrote:Nice find! I never noticed this before but mine does the same. Driver 1.093, TM 1.31, DSP 161.
Turn the Reverb send all the way up on a mic pre channel and Reverb return fully up on an output you'll be getting a low level but audible hiss - of course, because the inevitable input noise is sent to the Reverb. Interestingly, its volume does not depend on the mic pre's gain setting for Mic 9 but it does for 10 through 12 - at least on my unit.
Doing the same on an analog line input the hiss is still there but sounds as if it's gated/chopped off randomly. The noise is also recordable when turning on the loopback function for the output.
Is this what you're getting, Dom?