The invention relates to an LED light source comprising a light unit and a hollow curved cap covering the light unit. The light unit comprises a plurality of light emitting diodes (LEDs) distributed in the form of a spatial arrangement having a center position. The plurality of LEDs includes at least two different types of LEDs. Each type of LED is arranged for the emission of radiation within a different wavelength range. The cap is substantially transparent for radiation emitted by the light unit. The cap is further provided with an axially symmetric protrusion forming a depression in the exterior of the cap. The symmetry axis of the protrusion substantially coincides with the center position of the spatial arrangement of the plurality of LEDs.