Using ART SLA-1 130W/channel studio monitor amp for HD500X. With all volume controls on HD500X at maximum the input led on the ART don't even light. So I'm running the output into a Spirit Folio Notepad, mic channels with preamp on. That gets the gain to trigger the ART input LED and gets the full volume out of the amp. Maybe there is a mod for the HD500X to get the ouput to 1 volt. Otherwise, is there a good quality low noise stereo line preamp out there? I haven't been able to find any except for those in the small mixers. But it's awkward getting to the mixer controls in the rack. A rack mixer would make sense, but not when a Behringer 802 is $80 or so. Any ideas?