[Daniel, Torrey]

Tried locking the filter cavity with and without the high voltage amplifier. This can be done by scanning on the laser frequency instead of the piezo, while still locking with piezo. From 11454 you can see the 3db roll off point is ~10 kHz. IMG_0068.png shows that the amplitudes to not differ until this point, at which point the cavity lock with the HV amplifier in place rolls off in amplitude much faster. Additionally the phase is much better with no HV amplifier.