This is a review and detailed measurements of the HifiBerry DAC+ Pro XLR. It was kindly purchased by a member and drop shipped to me. It costs USD $59.90 which is quite cheap for balanced output. I think the cheapest stand-alone DAC with XLR output that I have tested was US $150 ( Massdrop Grace SDAC Balanced ). Even including the cost of the Raspberry Pi, you are less than $100 here and you get streaming functionality to boot.Here is what it looks like:The giant XLR connectors dwarf the rest of the board. They are sturdy though and had no trouble supporting the weight of my XLR cables although the rest of the unit as you can imagine, is quite unstable. You would need to weigh it down somehow to keep it from following the XLR cable to the ground or wherever it goes.The Pro designation in the name means that it has dual clock oscillators instead of using the poor quality clock that the Pi generates (they are the two rectangular parts near center right). XLR means exactly that. Instead of the RCA jacks in regular HifiBerry DAC+ Pro which I just reviewed, you get balanced XLR outputs. This is nice because it sharply reduces the possibility of nasty ground loops which are hard to deal with it when they bite you.The heart of the device is the TI PCM5242 DAC chip with balanced outputs. Its rated distortion and noise is 94 dB (SINAD). Let's see if the actual implementation gets there.Here is our dashboard view:Output voltage of 4.2 volts is slightly higher than nominal value of 4 volts we like to see which is fine. Alas, total SINAD (signal over noise and distortion) falls short of TI spec of 94 dB. But maybe TI means distortion alone in which case, we are there with third harmonic peeking its head to that level in the FFT graph above.The measured SINAD places the XLR version just behind the RCA version:That is not a significant factor though. Compared to Grace SDAC, we have a shortfall of 5 to 6 dB.Jitter performance is good and similar to RCA version:Multitone performance is again similar but perhaps a hair worse:Filter response is identical:The HifiBerry DAC+ Pro XLR has performance that is essentially identical to RCA version of it. You pay $20 more which to me is a reasonable insurance to pay against ground loops. Sadly the inclusion of XLR doesn't bring better fidelity.Overall, based on low cost of the solution I am going toeven though I wished it had better measured performance.------------As always, questions, comments, recommendations, etc. are welcome.Have to do a bunch of system upgrades and that is costing money. So appreciate anytoward that using: