A servo valve assembly, comprising: a housing defining a cylindrical cavity having a central axis (C-C), wherein the cavity includes a first cylindrical portion having a first diameter (D 1), a second cylindrical portion having a second diameter (D 2), a third cylindrical portion arranged axially between the first and second cylindrical portions (141, 142) having a third diameter (D 3) smaller than the first and second diameters (D 1, D 2), and a pair of transition portions defining opposing conical cavity surfaces (144, 145) that each connect a respective one of the first and second cylindrical portions (141, 142) with the third cylindrical portion; a spool disposed in the cavity and co-axially aligned with the central axis (C-C); wherein the spool comprises a pair of blocking members (130a, 130b) projecting radially therefrom, and each of the blocking members (130a, 130b) defines a conical blocking surface (134a, 134b) opposing a respective one of the conical cavity surfaces (144, 145) to define a fluid flow passage therebetween; wherein a cone angle (θa, θb) of each conical blocking surface (134a, 134b) relative to the central axis (C-C) is equal to a cone angle (θa, θb) of the opposing conical cavity surface (144, 145) relative to the central axis (C-C); wherein the spool is moveable along the central axis (C-C) to vary a flow area of the flow passages between the conical blocking surfaces (134a, 134b) and the conical cavity surfaces (144, 145); and wherein the spool further comprises a pair of guiding lands (124a, 124b) extending radially from the spool and disposed in the third cylindrical portion, the pair of guiding lands (124a, 124b) configured to contact a cavity surface defining the third cylindrical portion to support the spool in place along the central axis (C-C), wherein the guiding lands (124a, 124b) each define a plurality of circumferentially extending guiding surfaces (127a, 127b) spaced circumferentially apart by a plurality of grooves (126a, 126b) that extend axially through the guiding lands (124a, 124b), wherein the guiding surfaces (127a, 127b) contact the cavity surface defining the third cylindrical portion and the plurality of grooves (126a, 126b) allow fluid communication axially across the guiding lands (124a, 124b). a housing defining a cylindrical cavity having a central axis (C-C), wherein the cavity includes a first cylindrical portion having a first diameter (D 1), a second cylindrical portion having a second diameter (D 2), a third cylindrical portion arranged axially between the first and second cylindrical portions (141, 142) having a third diameter (D 3) smaller than the first and second diameters (D 1, D 2), and a pair of transition portions defining opposing conical cavity surfaces (144, 145) that each connect a respective one of the first and second cylindrical portions (141, 142) with the third cylindrical portion; a spool disposed in the cavity and co-axially aligned with the central axis (C-C); wherein the spool comprises a pair of blocking members (130a, 130b) projecting radially therefrom, and each of the blocking members (130a, 130b) defines a conical blocking surface (134a, 134b) opposing a respective one of the conical cavity surfaces (144, 145) to define a fluid flow passage therebetween; wherein a cone angle (θa, θb) of each conical blocking surface (134a, 134b) relative to the central axis (C-C) is equal to a cone angle (θa, θb) of the opposing conical cavity surface (144, 145) relative to the central axis (C-C); wherein the spool is moveable along the central axis (C-C) to vary a flow area of the flow passages between the conical blocking surfaces (134a, 134b) and the conical cavity surfaces (144, 145); and wherein the spool further comprises a pair of guiding lands (124a, 124b) extending radially from the spool and disposed in the third cylindrical portion, the pair of guiding lands (124a, 124b) configured to contact a cavity surface defining the third cylindrical portion to support the spool in place along the central axis (C-C), wherein the guiding lands (124a, 124b) each define a plurality of circumferentially extending guiding surfaces (127a, 127b) spaced circumferentially apart by a plurality of grooves (126a, 126b) that extend axially through the guiding lands (124a, 124b), wherein the guiding surfaces (127a, 127b) contact the cavity surface defining the third cylindrical portion and the plurality of grooves (126a, 126b) allow fluid communication axially across the guiding lands (124a, 124b).