• Registered: 2017-05-04
  • Posts: 58

Topic: ADI-2 PRO Fs--type of balanced outputs/inputs

I apologize if this has been answered before. I need this information for proper integration with some unbalanced hi-end home audio equipment that is being designed/customized for me.

In reference to the balanced analog outputs in the RME ADI-2 PRO Fs, what exact type of balanced outputs are they,  i) “true balanced transformer” outputs or ii) “transformerless” electronically balanced outputs?

If they are “transformerless” outputs, are they i) “pseudo-balanced” phase/antiphase outputs using a buffer and polarity inverting opamps or ii) “cross-coupled” output stages each using two cross-coupled opamps mimicking a transformer?

Likewise, what exact type of balanced analog inputs are those in the unit?

Thanks in advance and best wishes for the Holidays,

dr.larkos

  • Registered: 2017-05-04
  • Posts: 58

Re: ADI-2 PRO Fs--type of balanced outputs/inputs

Could someone at RME kindly address this question?

3 Reply by MC

  • MC
  • MC
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  • From: Germany/Thailand
  • Registered: 2007-04-06
  • Posts: 25,586

Re: ADI-2 PRO Fs--type of balanced outputs/inputs

Sorry, missed that post.

The question about transformers - these are so seldom that any device having one explicitely mentions it.

The XLR outputs are described correctly in the manual, fully electronically balanced. Cross-coupled is called servo-balanced in RME products and technically limited to about +21 dBu - so not possble when an output can reach +24 dBu. The manual also clearly explains that this is not the case as you are not allowed to ground one of the two phase pins.

The XLR outputs do not use an inverter as the whole signal path from the DAC to the XLR output is balanced/symmetrically. This usually means that using only one phase (unbalanced) noise and THD is tarnished. Not in the ADI, a special circuit takes care of that, and this is also mentioned in the manual.

The analog inputs of the ADI-2 Pro are fully electronically balanced again, with identical input capacitance and impedance for both + and - phase. As is usual they also work perfectly servo-balanced , fully supporting unbalanced input signals.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2017-05-04
  • Posts: 58

Re: ADI-2 PRO Fs--type of balanced outputs/inputs

Thanks a lot, MC