I just bought a Marantz pm6004 and I have significant hissing noise when I access the phono setting before even putting on an LP. I compared it to my old Denon amp and the difference is very noticable. I have a fairly new Audio Technica TT that does not have a place for a ground wire in the back. I have emailed Marantz tech support but I wanted to check here to see if there is something I'm missing or if it just sounds like a defective phono stage in the amp.
Thanks
Dan