Either. That's the common sense meaning of " it says its TRS Phones output jacks , powered by 2 independent driver circuits, can be used as line outputs."
Which ever one gives you the level you seek with the volume adjustment you prefer on the preamp.
This is a microscopic issue in the cosmic scheme of things.
There are also some cheap audio transformers on the market:
Mouser Part No: 553-TY-250P
http://www.mouser.com/ds/2/410/Y-250P-346070.pdf
I would maybe not use it for +20dBu signals, but it should handle +6dBu signals well.
Not for the ones seeking lowest possible THD, but a nice cheap solution to get rid of hum if it is a problem.
Mouser Part No: 553-TY-250P
http://www.mouser.com/ds/2/410/Y-250P-346070.pdf
I would maybe not use it for +20dBu signals, but it should handle +6dBu signals well.
Not for the ones seeking lowest possible THD, but a nice cheap solution to get rid of hum if it is a problem.
Mentioned earlier.
Page 8 of the manual if anybody's still interested:
http://www.rme-audio.de/download/bface_pro_e.pdf
Dave.
Page 8 of the manual if anybody's still interested:
http://www.rme-audio.de/download/bface_pro_e.pdf
Dave.
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There is another potential issue with grounding one of the output phases beyond possible (but unlikely) driver damage. Doing so will sink current into the ground. And as we know all real world "grounds" have a finite resistance which means a voltage can develop across.
Bottom line is system crosstalk!
This is a very real issue in analog broadcast and mastering environments. The SMPTE timecode signal, is a 1200/2400hz bit stream. There is unfortunately a lot of equipment, primarily video based, that uses unbalanced connections for timecode, BNC or even RCA. In some cases if pin 3 is grounded, the high amplitude timecode, +4 to +8db, will contaminate the ground network and crosstalk into audio circuits.
This is further complicated as some gear uses output transformers, which require pin 3 grounded in an unbalanced hookup, and some are active drivers. So you have to be real careful of the pin 3 unbalanced problem.
There is a circuit that some manufactures use which monitors the output current on both phases and if excessive, the driver shuts down. This was a good solution to the Pin 3 unbalanced problem but not widely implemented due to cost.
Bottom line is system crosstalk!
This is a very real issue in analog broadcast and mastering environments. The SMPTE timecode signal, is a 1200/2400hz bit stream. There is unfortunately a lot of equipment, primarily video based, that uses unbalanced connections for timecode, BNC or even RCA. In some cases if pin 3 is grounded, the high amplitude timecode, +4 to +8db, will contaminate the ground network and crosstalk into audio circuits.
This is further complicated as some gear uses output transformers, which require pin 3 grounded in an unbalanced hookup, and some are active drivers. So you have to be real careful of the pin 3 unbalanced problem.
There is a circuit that some manufactures use which monitors the output current on both phases and if excessive, the driver shuts down. This was a good solution to the Pin 3 unbalanced problem but not widely implemented due to cost.
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I think it's more likely the person queried with that RME email was just not aware of the issue and/or didn't have the technical chops to understand the premise/issue of the question.
I have to agree with comments early on in this thread. Any commercial unit built with an output stage that would be damaged by this short circuit is questionable in design.
The language in the RME manual seems to indicate they've targeted a much lower output resistance vice preventing degradation of performance with a pin 1/3 short. Those XLR outputs will most likely look into a fairly high impedance load, so it makes no sense to me to have such a low output resistance.
I guess they're thinking about low-pass filter issues with really long cables. It makes sense from that aspect.
Dave.
I have to agree with comments early on in this thread. Any commercial unit built with an output stage that would be damaged by this short circuit is questionable in design.
The language in the RME manual seems to indicate they've targeted a much lower output resistance vice preventing degradation of performance with a pin 1/3 short. Those XLR outputs will most likely look into a fairly high impedance load, so it makes no sense to me to have such a low output resistance.
I guess they're thinking about low-pass filter issues with really long cables. It makes sense from that aspect.
Dave.
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Yeah, I think you might be right regarding customer service
Even if normaly the support at RME is excellent!
Still, grounding pin 3 works, even if not grounding pin 3 is better. I think the difference is mostly about measuring numbers and has little practical implication in most cases (108 dB vs 100 dB SNR). In the SMPTE leak case i agree there can be a practical problem using pin 3 ground.
Even if normaly the support at RME is excellent!Still, grounding pin 3 works, even if not grounding pin 3 is better. I think the difference is mostly about measuring numbers and has little practical implication in most cases (108 dB vs 100 dB SNR). In the SMPTE leak case i agree there can be a practical problem using pin 3 ground.
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