Abstract: In fluid pulsing apparatus operable in a drill pipe in a well in which well drilling fluid flows, wherein pressure pulses are created by restricting one or more of several hydraulically parallel paths, constant working pressure regulating valves with a long time constant relative to the transient pulses are constructed in the hydraulically parallel paths. The valves operate to produce a more consistent pulse character allowing production of pulses at low flow rates of drilling fluid that are of sufficient amplitude to be more easily detected on the Earth's surface and restriction of amplitude of pressure pulses at high flow rates of drilling fluid to limit equipment damage and loss of hydraulic energy. The valves function by varying the flowing cross sectional area of the hydraulically parallel paths.