Topic: ADI-2 DAC audible squeak from device
I recently became an owner of ADI-2 DAC [ESS version]. In my opinion, this is exceptional device, but...
I'm writing to You because from day one I'm observing strange high pitch noise coming from front of unit. This is some sort of high frequency squeak, coil whine. I observed that is correlated with two things: 1 - brightness of LCD below 100% and USB connection.
When display is turned off noise is gone. When brightness is set to 100% it is gone also. Noise is most audible at 50-70% of brightness.
Unplugging device from USB makes it completely silent. What's more, disabling DAC in operating system make squeak to disappear also.
Plugging device through iFi idefender changes nothing. When moving DAC to battery operated laptop problem still exists.
In my opinion it could related with interferences with PWM backlight regulation of LCD. During music session this is no issue. But in quiet environment in idle state squeak becomes audible. It is not loud, but I am quite sensitive to high frequency noises. AutoDarkMode is not satisfying workaround - I really like this beautiful display. :-)
My question: did anybody observed such behavior? Do you think that my unit may be faulty or maybe this is design flaw?
PS. Current firmware is 60/39. It was never updated. I see that 66/47 is available. Can it fix my issue?