I characterized the black Ithaca 1201 pre-amp that we had sitting in the racks. It works fine and the input referred noise is < 10 nV/rHz. I also checked that the filter selection switches on the front panel did what they claim and that the gain knob gives us the correct gain.

For comparison I have also included the G=100, 1000 input referred noise of one of the best SR560 that we have (s/n 02763) in the lab. Above a few Hz, the SR560 is better, but for low frequency measurements it seems that the 1201 is our friend.

As with the SR560, you don't actually get low noise performance for G < 100, due to some fixed output noise level.

Steve:  sn48332 of Ithaca 1201