Yes, I tested it against other preamps in stereo mode. I used the 7125 or an NAD C350 as the amps and switched preamps ONLY. All of audio is impedance matching and having a 1K ohm output impedance feeding into a 50K ohm input impedance in the 7125 or the NAD sounded veiled compared with a pre-amp with a 100 ohm output impedance. I was not the only one who heard this. I am not knocking the 990, it is a very good pre/pro, but it is not as good in stereo as many other pre-amps. Do a comparo yourself!

In general you want to keep the output impedance of a preamp at 100 ohms or below. The input impedance should be around 50K ohms or better.

Tim