I just tested my PA5 for you, paying extra close attention, and it does make a very quiet 'tick' in my speakers when I turn it on, and slightly more noticeable 'tick' when I turn it off using the front switch. I don't really hear this in normal operation though. My PA5 is also not truly 100% silent, but I can't hear anything unless I put my ear POINT BLANK against the tweeter of my Revel M105's, and then I can hear the faintest of noise.
To exaggerate the noises I just explained, I put my iPhone 12 Pro's microphone in direct contact with the tweeter grill on one of the Revel M105's and recorded the power on followed by power off 5 seconds later, and you can hear all of it since the mic is just a few mm from the tweeter.
I uploaded the audio to SoundCloud. Here is an explanation (mic point blank on tweeter the whole time):
- tick at 2s is the physical sound from 1M away of me flipping the PA5 power switch (a good reference for loudness)
- a quieter tick at 5s is from the tweeter after the PA5 is powered on
- there is a tiny increase in noise from the tweeter that can be heard from that point until 10s
- a final tick at 10s is from the tweeter when the power switch on the PA5 is turned off
https://soundcloud.com/dan-cunningham-764711364%2Fpa5-speaker-tick