I'm hoping an XD-V75 owner can help me confirm something...
A brief background - we have 14 units, rackmounted in a set of 8 and a second set of 6, along with various P180 and P360 antennas. All using the supplied correct UK power adaptors. We don't have any THH handhelds, only 14 beltpacks, which are used with a mix of cheap omni lapels and headsets, and then our more pricey set of Sennheiser MKE2 and Countryman B3s.
Basically, we've always experienced a constant background hiss on all 14 receivers (from XLR and jack) and I'm just trying to establish whether this is normal, or whether I need to send a set in for testing.
With our set-up, if you take an XLR out from any receiver, straight to any channel on the mixer (tried with a Yamaha 01V96 and a Behringer X32), and set the pre-amp gain to around 25db it'll be totally silent. If you then turn on the beltpack which is on that RF channel, you immediately get a constant hiss - regardless of whether a mic is connected to the beltpack or not (obviously if you do connect a mic then you get a bit of mic noise added too!) If you turn the beltpack off (but leave the receiver on), the hiss is completely gone.
Admittedly, this is only an issue during quiet passages of speech, because any singing with, say, one of the MKE2s mounted at the hairline, makes any hiss inaudible in practice anyway.
The fact that I've not seen anyone else mention this in the forums makes me think that there could be a fault - but on the other hand, we have the same issue with all 14 units!
So could someone please try this (Ron?!) - how much pre-amp gain are you able to add on the mixer before you can hear any hiss if you PFL the channel and listen on headphones? Plus, does this noise go away if you turn off the associated beltpack?
If you increase the digital gain on the receiver, the hiss just increases proportionally. I've ruled out the cables etc - if you plug an SM58 into the end of the cable, instead of the receiver, you can set the pre-amp gain as high as it will go and there's no noticeable hiss.
I even tried taking one unit out of the rack so that it wasn't surrounded by other bits of metal, but it made no difference.
Incidentally, I'm not talking about ridiculous levels of gain before this hiss emerges. Obviously I'm not expecting any piece of audio equipment to be completely silent, but I'm confused because this is a prominent enough issue that I'm sure someone else on here would have brought it up by now! Unless I have a hardware issue with all 14 units...