An in-line heating device for a liquid food or beverage preparation machine in which liquid is circulated through the heating device and then guided into a brewing chamber. This heating device includes a thermoblock with a metal mass that incorporates an inlet, an outlet and a heating chamber extending therebetween to form a passage for guiding the liquid circulating through the mass, with the mass arranged to accumulate heat and to supply heat to the liquid; and one or more electric components that are rigidly secured onto or into the thermoblock and that are connected to a printed circuit board or a flex-print arranged to control the thermoblock. The electric components are rigidly connected to the printed circuit board or flex-print, in particular via rigid connector pins or blades or rigid plug and socket members.