In walnut cabinet. The M3 is a three valve primairy receiver.
The controlsand the valvesare all located on
theebonite front.
Connections and knobs
from left to right: aerialandground busand alinkplug formedium waveandlong wave.
Thetuning coiland the feedback coil
are situatedabovethe
tuning knobwithfine tuning.Below
thethree tubes,tworheostatsforthe filament(the firstforthe detector andthefirst LFvalve,
the second one forthe power tube)
and at the right, jacksforthe speaker andheadphones.
The radio was designed by British engineer George William White,
who worked for NSF.
The receiver was equipped with the low-voltage valves A110, A110,
and
A106, so the batteries could be placed inside the set. Later the valves
were replace by the 4 volt valves A415
(2) and a B405. The polarity of the filament current has to be
reversed in this case. Please note that in the circuit in later
Philips manuals, shown below, the polarity also has to be
reversed.
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