While the C2 uses a 19V transformer, I think the R2 uses a 24v transformer. The main electronics board appears to be the same for the C2 and R2. The board is also rated for 24V. I bought a higher power 24v replacement transformer to see what difference it might make, and provide enough power for a possible future heated bed. The original C2 Transformer output: 19v @ 4.75 amps; measured idle power: 3W (i.e. C2 off) The new transformer: 24v @ 6.25 amps; measured idle power: 4W With the C2 off, and cooled for 30+ minutes, the startup time, from selecting a previously printed item to print, to starting to extrude dropped from 133 seconds to 54 seconds, a 79 second improvement. With 24V the extruder heats up faster, and the test print started as soon as the bed calibration completed. I'm not sure the 24V makes any difference for printing speed or any other aspects of C2's operation, but it does have plenty of power for future mods. The 24V brick is almost double the size of the Robo 19v brick if that matters to anyone. This is the unit I bought on Amazon - http://amzn.to/2xFsZ2F. This UL-listed unit has the correct sized DC plug. There are alternatives, but I prefer to get UL-listed transformers, as they tend to be safer and more reliable. On the 19v unit, I saw peak power of 50W, with 41W typical when printing (measured at the outlet). I forgot to check the new unit, but I don't expect much change. I assume the primary reason the R2 uses 24v is for the heated print bed and two extruders consume a lot more power. With 24V these will all heat up to temperature faster. The rest of the electronics uses 12v or 5v, regulated down from the input voltage, so the choice of 19v or 24v doesn't matter for the electronics.