"One theory would be that you mixed it up and there is only one input buffer with two output buffers. The one input buffer would only be used to create the "inverted" balanced signal when a single-ended RCA input is used. Then it goes to the discrete FET stage, which should be fully balanced/differential. Then there are two output buffers for both the normal and inverted signals of the XLR connection."
So upgrading the input buffer would only improve the sound of the RCA inputs and have no affect on the balanced input signals?
So upgrading the input buffer would only improve the sound of the RCA inputs and have no affect on the balanced input signals?