This is a low frequency type to be followed in the circuit by a transformer coupled directly heated power tube. This tube was also available metal sprayed.
Bibliografia
Taschenbuch zum Röhren-Codex 1948/49
Wireless World (The), London (WW, 79) Advertisement Dec 2 1931
- - Manufacturers Literature
YN4: Triotron Radio Röhrenbroschüre 1928
Thomas Lebeth
Just Qvigstad
YN4: Triotron Radio Röhrenbroschüre 1928
Thomas Lebeth
