Well, this could be a power station switching issue. Call up your power company and ask them if they are doing anything at this time. They often do not monitor power quality closely enough to tell when they have bad switching issues.
It sounds like your DAC is switching to the wrong sample rate or a similar problem. This can happen if the power has been interrupted or it gets a surge from somewhere.
Another source of a problem is a scheduled job on your PC that causes this, such as your anti-virus refreshing. Check the logs and see when it last updated.
I would try watching your computer processes (Process Monitor?) and see what is running during the distortion. If you have a way to substitute a laptop or old computer for the new one you may be able to rule out the computer completely. But not the peripherals that are shared.
It's the fact that the duration of the distortion is always 3-4 seconds only - not longer , not shorter and only once per night - just at different times during the 3 hour timeframe
If it was interference from outside - why always the same length?, and why only once?
The 3 second of distortion on it's own is no big deal from my perspective - just don't want it to be slowly frying my speakers - even though I recognize it straight away and immediately turn the volume down - it may happen when I'm out of the room
Do you live in a single family home or multi-unit building? Does someone in your residence or a neighbor return home during that time window and switch on some device, like an air conditioner or something that might be drawing a heavy load for a couple minutes and possibly interfering with your power?
Yes I live in a 5 unit group - 3 units in my block and a separate block of 2 units
Entirely possible that my neighbours are coming in and out and switching on AC, devices etc- But this has only started happening 12 nights ago - nothing has changed in my system and neighbours are the same - and I've been home for the last 2 months and haven't seen any work installing new AC etc
It's a burst of data flowing inside the computer that's causing the interference. Or maybe it's a bad bit if memory and the time >s irrelevant or only relevant to the extent that is the time you typically use it for this purpose.
I do not think the issue originates your power company. I think @carlsbad's suggestion to test a Roku in your system is a good idea - it will help narrow down the source of the problem. Process of elimination.
You must have a verified phone number and physical address in order to post in the Audiogon Forums. Please return to Audiogon.com and complete this step. If you have any questions please contact Support.