Periodic, bad, 'screechy' sound, right? Almost like a finger-on-chalkboard?
Please check the software rev of your 840. This guy, with original software is very intolerant of poorly clocked signals.
How do I KNOW? Well, my 840c simply doesn't like the optical feed from my Apple Airport Express. See above for noise symptoms/effects.
The CURE? Well, send off to CA. They'll be more than glad to ship you off the UpDated software. It comes as a ZIP file with instructions and the update itself.
They want you to use a certain version of Windows. (XP?) You'll also need a NULL MODEM cable, which is a serial cable with its wires crossed.
Now, I've not had the GUTS to do this to my player. Simply Chicken. My CA dealer offered to do the upgrade 'for a price'....TBD? Personally, I think CA should kick down and just DO it. If I were to 'doorstop' my player, I'd really be pissed.
It also makes the SAME noise with the optical feed from my Small Dish (DishNetwork) receiver, though mainly on music and quite infrequently.
The Sterophile test showed the AirportExpress to have some of the worst jitter they ever measured. If a product like WADIA has the same problem, I'm not sure there IS a fix, unless one of 2 things. You either got a lemon (Wadia) or the CA player is junk and unusable as a double input DAC,.
