Applicability
Please note that this upgrade applies only to the V2.1 version of the LDR3x Passive Preamp Controller which have a socket for swapping out the auto-cal op amp. If you attempt to retrofit this op amp into the earlier V2 version you will have to cut out the original op amp, remove the pins from the through-hole solder pads, de-solder the solder pads and solder the upgrade op amp in its place. Do not attempt this unless you are comfortable with this type of electronic component extraction since there’s a real risk of permanently damaging the auto-cal board and possibly also rendering your V2 inoperable.