This configuration of the amplifier is useful in systems with two or more photomulipliers (as a different offset can then be applied at each detection wavelength).
In exclusively multiple excitation set-ups we would recommend purchasing input amplifiers; as having fewer controls they only occupy half the space in the system rack. This is our standard module for accepting signals directly from a photomultiplier in a multiple excitation system. In this mode the input is configured as a virtual ground, but it can also be configured as a voltage follower for connection to other photodetector systems, and the gain in both modes is internally programmable over a 100:1 range.
The module integrates the incoming signal for each filter position, and the integrals are corrected so that they are independent of the rotor speed.