I'm curious as well to see if your replacement base is any different in terms of base coil whine. I submitted a ticket on March 8 about my bases coil whine. Like your base, not only does my base have it, but it has that same "grainy" feel. Is that normal? I'd sure like to know, but nobody from Fanatec has bothered to answer my support ticket. I've since submitted a second ticket 9 weeks after the first. Maybe they'll answer that one? Suffice it to say, their support ticket system is broken. You follow the instructions, but when you enter "Submit" you get the error "MUST FILL IN SUBJECT FIELD" even though one was entered. It took 5 tries until I finally got the "A ticket for this product has already been submitted. Anyway, I digress.... Other than that, the base works perfectly fine on firmware 457 with no disconnects whatsoever. And speaking of disconnects, I have a theory to what may be happening to those who have it.
The theory is...PlayStation uses a security chip and protocol for it's "official" products. When you plug in a supported hardware device, there's a "handshake" between the console and the peripheral. From what I've been told, this handshake is not a one time deal. The console will periodically check for the "handshake" while the system is on to make sure everything is on on up and up. For those of you who may be familiar with the Cronus Max device from Collective Minds, it allowed you to use "non-licensed" devices on your PlayStation. I for one used one of these things for several years. It allowed me to use my then Fanatec Club Sport 2.0 belt drive base (Not Supported nor licensed by Sony) to work on my PS4. You simply plugged in your base to the Cronus Max and a slave PS controller to it. The Cronus would then plug into the PlayStation. The SONY PS controller would serve as the "security chip" bypass. It surprisingly worked well and for me it worked like a charm until I got into league racing. That's when I noticed "input lag". Anyway, it worked. Every once and a while, Cronus had to update their box to fix issues that arose with SONY PlayStation firmware updates as well as improving game functionality. One of these updates related to how Sony arbitrarily changed the "handshake test". Cronus figured out what they did and thusly fixed their box when people where having disconnect issues. This all leads to my theory. I think it's possible that FANATEC and however they and Sony are dealing with the "handshake" is either broken, glitched or something. Maybe their are a batch of faulty security chips in these bases? Sony, supplied them to FANATEC, so maybe a bad batch? The disconnect issue that people are reporting is different from disconnect issues I've encountered with my DD PRO. When that thing disconnected, you had to REBOOT the base and or the PlayStation as well. From what, I've read, the disconnect issues here, the base momentarily disconnects, then comes back.
Anyway, it's just a theory. I'm just glad mine doesn't have that issue. I just wish someone at FANATEC would answer my coil whine ticket. LOL