Hey @fastfreight
When an amp or preamp has XLR inputs there are three things that may be done:
- Ground one signal pin.
- Use a transformer to convert to single ended
- Use op amps in differential configuration
- Very very rare - use discrete circuits to convert
The first case looses any noise / long distance benefits of the XLR cables. The connector is a convenience feature. The second is fully discrete but subject to bandwidth and distortion limitations of the transformers, may add character all its own. Third is the most common and I’m sure you don’t even know how many times that was used in creating the music you listen to.
Professional devices, from microphone preamps to mixing boards and tape recorders almost all rely on op amps as the inputs and convert the signal from differential to single ended before doing whatever they will do with them, so keep that in mind when evaluating whether this is good enough for you.
Like any active devices they may add noise or distortion, but it is only at the end of the chain that Audiophiles become obsessed with them!
I would not say they have any specific sound by themselves or their use, so it IS good to test with them. Also, while XLR is "professional grade" and bigger and more complicated there’s no guarantee at all in a home away from radio towers and machinery that you’ll ever hear a difference. If you have a long run to a subwoofer, or to active speakers in your surrounds you might as well go with XLRs to ensure the least likelihood of noise pick up though.
