Loewe 3NF
The Loewe 3NF was an early attempt to combine several functions in one electronic device.[1]
Produced by the German Loewe AG company as far back as 1926, the device consisted of 3 triode valves (tubes) in a single glass envelope together with all the fixed capacitors and resistors required to make a complete radio receiver. The resistors and capacitors had to be sealed in their own glass tubes to prevent them from contaminating the vacuum.
The only other parts required to build a Radio receiver were the tuning coil; the tuning capacitor and the loudspeaker. The device was produced not to enter the Integrated circuit era several decades early, but to evade German taxes levied on a per valveholder basis. As the Loewe set had only one valveholder, it was able to substantially undercut the competition. The resultant radio receiver required a 90 volt HT plus a 4 volt LT (A and B) battery (the HT battery provided not only 82.5 volts for the HT but also two grid bias supplies at -1.5 volts and -7.5 volts).
One major disadvantage of the 3NF was that if one filament failed, the whole device was rendered useless. Loewe countered this by offering a filament repair service.
Loewe were to also offer the 2NF (two tetrodes plus passive components) and the WG38 (two pentodes, a triode and the passive components).