Well, my email to PS Audio resulted in this message from them:
"Hello Alexandru,
I would be more than happy to provide a replacement cartridge. Please give me your shipping address, and I will get one sent out today."
Thus they implicitly acknowledged that 127V should not trigger a shut-off.
I, one, consider that to be good customer service even if their product was not perfect.
I could only wonder at what the outcome would have been had one accused them of damaged equipment due to inadvertent and repeated "on-off" cycles...
I had the unit for a while powering a PS Audio DLIII DAC and I didn't realize something was wrong until I changed that DAC for a Wyred 4 Sound DAC2. Sometimes I saw the DAC2 "losing its previous settings after a night spent in standby".
This is what triggered my investigation as I intially thought the W4S had a problem.
A recent late listening session, at 2AM in the morning, caught the Duet "in the act". And when it turned back on, it wasn't pretty, for my power amp was on.
That really got my attention.
I quickly plugged a voltmeter in an outlet and saw 127V.
I unplugged my components from the Duet and watched it alone for a while. As soon as the voltage got to 127 it was shutting off. When the voltage was back to 126.8, was back on. And again, and again... I remembered my childhood when I was playing with the light switch to the point of making my dad start a foot chase after me.
I could only think of how many time the PS Audio DAC was turned off and on during the night without any telltale sign.
But it didn't complain and didn't flinch.
In spite of all these, I truly like what the Duet does for the sound quality. As I discovered the issue (last Friday), I took it out of commission and immediately felt the difference without it.
I do have surge protection at electrical panel level, thus the Duet was for filtration only, and did/does a great job.
Let's see what the new cartridge will do...
Alex