Abstract: Disclosed herein is a light source apparatus for providing an adjustable number of wavelength channels. The light source apparatus comprises at least a first plurality of LED modules, each LED module comprising an LED, a housing which at least partially encloses the LED, and a light director attachable to said housing for directing light emitted by the LED. The first plurality of LED modules are attached to a support structure in a first arrangement via attachment means. In the first arrangement, light emitted by each LED of the first plurality of LEDs is directed along a first optical axis. At least one LED module of the first plurality of LED modules is a removable LED module, and the attachment means is configured to allow the removal and re-attachment of the removable LED module to and from the first arrangement.