• Registered: 2010-11-02
  • Posts: 2

Topic: Voltage measurements on 1/4" TRS Line Outputs - non symmetrical

Hello all,

Besides a lot of converter gear from RME I use the Fireface 400 for acoustical measurements.
While trying to calibrate my measurement chain I wanted to measure the voltage at the 1,4" TRS outputs at a certain output level setting.
I used a sine wave as test signal. The utilized multimeter was able to detect the sine waves frequency correctly.

The problem ist, that I measured different voltages between tip and sleeve and ring and sleeve. eg. 3V and 1,1V. This behaviour is the same on all TRS outputs, but with different values.

In my unterstanding, with the symmetrical concept the absolute voltage should be the same between tip and sleeve and ring and sleeve.

Do your devices behave in the same way?

@RME Developers: Is this the desired behaviour or a device failure?

Best regards,
dreadnaught.

2 Reply by MC

  • MC
  • MC
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  • From: Germany/Thailand
  • Registered: 2007-04-06
  • Posts: 25,599

Re: Voltage measurements on 1/4" TRS Line Outputs - non symmetrical

A deviation like that is a bit high, but rest assured that it has no meaning in real world. Only the voltage across Tip and Ring is of interest, and that one should be correct. Additionally the CMRR function of balanced lines is performed by the receiver, not the transmitter, so again a deviation of the output voltages will not cause malfunction.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2010-11-02
  • Posts: 2

Re: Voltage measurements on 1/4" TRS Line Outputs - non symmetrical

Hello,

thanks a lot for the quick reply. So if I want to measure the devices maximum output voltage I take the voltage measured between tip and ring?

Best,
dreadnaught

4 Reply by MC

  • MC
  • MC
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  • From: Germany/Thailand
  • Registered: 2007-04-06
  • Posts: 25,599

Re: Voltage measurements on 1/4" TRS Line Outputs - non symmetrical

That's what I wrote, yes. And it will be identical to the one between tip and ground if ring is connected to ground.

Regards
Matthias Carstens
RME

MC's Website