Yamaha must have had all that in mind when it introduced its superb M-70 power amplifier. ... If you happen to own 4-ohm loudspeakers, the amplifier will pump up to 250 watts per channel into them, providing they are able to handle ... Here two circuit innovations are brought to bear. ... P may be installed directly in the aquot;P- mountaquot; (plug-in) type of tonearm such as thai found in the linear-tracking turntables.