Rai Weiss designed a low noise FET input amp using the [[attachment:IF3602.pdf]] which should have an input voltage noise of 0.3 nV/rHz.

Josh Myers (of LHO) made a PCB version of it ([[http://www.ligo.caltech.edu/docs/D/D060205-A/|D060205-A]]).

It is basically a differential amplifier made up of the IF3602 dual-FET followed by a LT1128. It has 9V batteries for power.

We want to make a newer, better version of this preamp.

=== Notes on the New Version ===
 1. Use panel mount BNC, not board mount.
 1. LED indicator of battery health should be a temporary 'Batt Test' switch, not an always on.
 1. Need an alternate input for power (e.g. Banana from the SR560, or the 3-pin D of LIGO standards).
 1. Needs voltage regulators inside for the power input.
 1. Metal film resistors. For the 5 Ohm resistors, we just parallel some 10 Ohm ones.