Mazda designation system

1. Signal tubes
For example: 6F22
1st letter heater
1 1.4 V parallel or serial
6 6.3V parallel or serial
10 0.1 A serial
20 0.2 A serial
30 0.3 A serial
next letter(s) construction
C frequency changer with oscillator section
D signal diode(s)
F tetrode or pentode
FD tetrode or pentode with diode(s)
FL tetrode or pentode with triode
K gas-filled triode or tetrode
L triode or duotriode with oscillator triode
LD triode with diode(s)
M tuning indicator
P power amplifier tetrode or pentode
PL power amplifier tetrode or pentode with triode
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2. Power rectifier tubes
letter(s) construction
U half-wave rectifier
UU full-wave rectifier


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