I have updated the PDH servo schematic to include:

• LF356's instead of AD829's for the switchable stages. Rich said it was a good idea to have FET input op amps in this case (like on the universal board). The LF356's have a relatively low GBW of 5 MHz. This shouldn't be a problem since we don't use them at high gain, but in any case we can switch to the LF357 which has a GBW of 20 MHz.
• External compensation capacitors for the AD829's, which we will still use for the input, output, and buffered monitor stages.
• Buffered monitors before and after the EXC injection (for TF purposes)
• RF phase shifter with independent +12 supply (not exactly sure why that is there, but that's the way it is on the universal board)
• LED indicators for
  • +12
  • -12
  • +12a (RF)
  • Boosts 1-4
• Test points for
  • +12
  • -12
  • +12a
  • +5 (comparator supply)
  • various places around the circuit we might want them

I hope to be able to position all the BNC/SMA/LEDs on one edge of the board so that we can have them sticking out the face of the NIM module. We can use Front Panel Express to make a fancy face.

We still need to talk about the variable gain stage. Koji doesn't like the linear-in-dB unit, so the other alternative is to have an amplifier with a pot in the feedback path. Does anyone else have any feelings for/against this?