There is a quick test to see if your receiver is the new version,or old version (I just got done checking two receivers for my buddy) connect two Hi-Tec digital's on a Y harness and try it....if it is the old version they will be very unstable.

Even with one servo the signal is very unstable with a hi-Tec digital connected

Photo #1 shows the output of the receiver connected to one H-Tec Servo on the top trace
The bottom trace is the signal through a line driver (amplifier), notice that the signal on the bottom is around 4.8 V where the signal on the top is around 2.8 v

Photo # 2 is with the output of the receiver connected to two Hi-Tec servos, notice that the bottom trace the pulse width is widened (out of compliance)

Photo #3 is the output of the receiver connected just to the line driver, the output of the line driver is connected to two hi-tec digital servos, note there is no more distortion of the signal, and the levels are around 4.8V

Bottom line is I would not trust running any hi-tec digital servos with out using a line driver on the older receiver.