Brian, they go through a gain stage, or just an attenuator? I never tested it, but I didn't think you could actually amplify the line-in signal. Pretty cool, actually.
Good question. I remember a note from Doug mentioning the specific op amps used through the RCA inputs, but I don't think I have the email any longer so I can't relay the specific op amp number.
Had to do a bit of
research, but apparently op amps are used to amplify the differential between two input voltages and are thereby able to provide an increase in gain (positive voltage differential) or decrease in gain (negative voltage differential).
So...the answer to whether the RCAs go through a gain stage is: yes, an op amp gain stage (wish I had the part # from Doug's email). And I believe the op amp gain stage may be positive or negative.
but I think part of these mods actually improves the analog input and may actually improve the sound when bypassing the mic in and usind the rca inputs.
Nope, the Oade mods only upgrade the op amps through the XLR mic inputs, not the RCA inputs.