Abstract: An apparatus for assembling warps of spun fibers and/or filament yarns present on yarn beams to form a warp present on a warp beam is described. This apparatus has a pneumatic pressure regulator (1), an electromagnetically operable pneumatic valve (2) downstream of the pressure regulator, a three-position rotary disk valve (3) downstream of the pneumatic valve, and pneumatically operable brake cylinders (4) of the yarn beam brakes (12) which are arranged downstream of the three-position rotary disk valve and connected in parallel with each other and a pneumatic by-pass limited in time so that asynchronous pneumatic braking of the yarn beams and of the warp beam during rapid braking is avoided. The by-pass serves to bridge the switching time of the three-position rotary disk valve (3). According to one embodiment, the control of the pneumatic valve (6) switchable with delay and of the pneumatic valves (7 and 8) occurs pneumatically.