Induction motor; sound speed (24fps) only. Older versions of this model with universal motor had a motor brush cap and sound/silent speed switch.
Starting with the 60-series models, the model number suffix denoted amplifier output power rating in watts. I believe the tube amplifiers were rated in peak watts, a very optimistic figure compared to continuous, or RMS, watts.
The 25-watt amplifier of the 70-25 had a microphone input, whereas the far more common 70-15's 15-watt amplifier did not.