With a balanced system, we can easily flip the phase of the signal with the GlassWare Select-Phase switch and PCB. I get a lot of e-mail asking if I believe in phase. In other words, do I believe that we can hear the difference that phase reversal makes? I do. I have performed many experiments with phase and I have found that the difference is obvious, if one important stipulation is followed: you must pause at silence in between phase reversals. It doesn't take long, maybe a second or two, but this brief pause gives the ear and brain a chance to readjust to the change in phase. On the other hand, with no pause (and a two-position toggle switch), no difference can be heard with mad flipping back and forth. Wait a minute, the phase is correct on my system, so why would I need to flip the phase? Your system may be in phase (whatever that might mean), but the recorded music that you listen to need not abide to any fixed phase. Indeed, on the album, you can expect that some tracks are in phase and some out of phase. I have been told that recording studios know that phase makes a difference, so they purposely alternate the phase on tracks, so 50% of the time its right. ultimately, we need a computer-based media system that keeps track of the preferred phase for each track.
The Select-Phase switch has mute at the center in between phases. In addition, I like being able to park the output at mute, when I power down the piece of equipment and at startup, while the tubes get hot and are up and running.