They both do the same - short one of the signal conductors to ground. This would overload the output stage and cause distortion.
I have been looking for a suitable transformer based signal isolator for XLR -> RCA, but I have been noticing a couple of issues with them in different magnitudes
1. They cause non-linear distortion
2. They are (really) expensive
3. They (easily) saturate (clipping)
4. They might be locally unavailable (Jensen in EU)
5. They cause linear distortion
6. There can be (EM shielding?) performance degradation with cable length (most manufacturers do not mention anything about this though)
7. In general is is unclear whether the XLR -> XLR type isolators support XLR -> RCA cables (I am not knowledgeable on electrical engineering, perhaps this is obvious)
For instance, I have noticed somebody recommending a neutrik offering, but this device does not seem to handle professional signal levels. You really get what you pay for; I would not recommend this device without a high pass filter.
In this context, I was wondering whether there are other solutions, specifically
1. Are there active circuits/units for this?
No clipping, and must be cheap considering that even some cheaper amplifiers feature balanced inputs. I have not been able to find anything yet online.
2. Could I simply make a XLR to RCA cable where I do not short circuit one of the hot leads to the ground?
I cannot find this easily on google why shorting is necessary (again; I have no clue about electrical engineering). Thus, wire; ground -> ground, "+" -> "+" (leave "-" unconnected).
Another question; how bad it would be to overload the output stage of the DAC8 to begin with? Will this affect all channels? How much distortion are we talking about, considering that a transformer based isolator will also raise THD by orders of magnitude?
I will be using XLR -> RCA for subwoofers, and my stance in this is that I don't want to worry about clipping (render it absolutely impossible). So the current outlook is to buy the highest input rated transformer based coupler [Volt Second], apply a very steep FIR high pass filter at 10 Hz, and take care of the rest by lowering the volume on these DAC channels. The downside is that too much volume reduction will require me to reduce volume on other channels as well, and I expect this filter to induce large time delay.
I am curious about your thoughts. My apologies for the lengthy message.