Have heard of
another report that the ION-001 (and probably any ionizer) will degrade the sound if left on during playback. This comes from
@JEB42 on his SAT TT and arm and Atlas Lyra cartridge.
The green light does not affect the sound - if the unit is on during playback, we both reported hearing rolled-off highs, a slight muddiness, in the sound. That may not translate to other systems or some may prefer it; but it’s certainly changing the sound.
If you are curious, flip the ION on and off during playback and listen carefully. It’s also easy to do a blind test by asking a friend to flip it on and off with the green light off.
Going back to basics:
a humidifier and humidistat are all that is needed to maintain adequate room humidity. You can buy both for under $100. You set the amount of humidity based on the outside temperature, or until you do not see condensation on the inside of the windows. Using something like an ION because your room is too dry is not the right use of the technology.
If room humidity is correct, there is minimal to no need for a device like the ION. Ionizing just before playback is therefore more than adequate.. Static will not build up during playback if the room humidity is correct.