I'm able to TX and RX just fine using my 857 and SignaLink, and able to get the RX noise set to 0dB without a problem. What I've noticed, is that if I leave the computer unattended for several hours (ie: overnight), I come back and the RX noise has dropped to -30dB, without changing any settings or whatnot. Computer does not go into sleep mode, no screensavers are activated...
Any ideas or suggestions to try?