^Your losses may not be high enough to be noticeable.. I guarantee they're there, though. If there's no signal boosting circuitry, then there are losses when you split a signal. It's the laws of physics that dictates this, not me..
An example of this is an audio system (which works just like a galvo amp, even at the same frequencies). Let's say it's a stereo system with only two speaker outputs. If you attach only two speakers to the system, then each speaker will get the full output from each amp output. If you split each channel off to two speakers (for a total of four) each speaker will only receive a portion of its original signal. In an audio system, you can counter these effects (to a certain degree) by using speakers with a lower impedance value, but even then each speaker is not getting the full input signal.
The bottom line is that the output from the DAC is only so powerful. This power gets distributed across the entire network of conductive material that the outputs may be attached to. Unless there is a source of more power somewhere, as the network increases in size the more the power decreases at any single point on the network. Also, the number of connectors and wire length play into this to a large degree, although how much exactly is determined by the frequencies involved.
With 50m of cable, you may even be getting a little loss from the cable length. What I think is the case is that you are only splitting once off of the original outputs. Most likely this is not causing enough of a loss for you to notice, but if you were to connect more scanners and split more and more off the same source, the more you would notice the losses. You can't just keep splitting a signal over and over and over and expect it to remain at the same power. It's just not possible. Since the connection between the DAC output and the galvo amp input isn't really impedance dependent (in contrast to the speaker outputs I mentioned above), the losses aren't really as large as I previously stated so splitting only two or three times might work out.. Still I say to be prepared to use an amp, especially if you're trying to split many different ways. Not only will it overcome any of these issues, the drlava correction amp provides pots to tweak each channel for maximum signal quality. If you were to build an amp, most likely you'd end up incorporating a method of adjustment into it as well.
