Audio Note Mono Block 300b/2A3 - Section 5: Building and Installing the Filament Board

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Section 5: Building and Installing the Filament Board
We are now going to build the Filament Board for the Mono Block Kit.
The Filament Board takes the AC voltage from the Secondary of the Mains transformer and converts it to the correct DC
voltage that the Tubes require. We are using the LM1084 Voltage regulator, which is actually adjustable – by setting the
resistor values R1 & R2 we can set a particular voltage. Therefore the individual values of these and other components
vary depending on the particular configuration of amplifier that you are building - please refer to the parts list tables below
and identify your configuration before continuing.
Configuration Description Value Designator
110R R2
300B Filament 5v
W5 & W7 inputs 0 & 8.3v (Green & Violet)
330R
R1
91R R4
Single Triode 300B
6SH7 Filament 6.3v
W6 & W8 inputs 0 & 8.3v (Blue & Black)
360R
R3
100R R2
2A3 Filament 2.5v
W5 & W7 inputs 0 & 6.2v (Green & Black/Green)
100R
R1
91R R4
Single Triode 2A3
6SH7 Filament 6.3v
W6 & W8 inputs 0 & 8.3v (Blue & White)
360R
R3
110R R2
300B Filament 5v
W5 & W7 inputs 0 & 8.3v (Green & Violet)
330R
R1
110R R4
Parallel Triode 300B
300B Filament 5v
W6 & W8 inputs 0 & 8.3v (Blue & Black)
330R
R3
100R R2
2A3 Filament 2.5v
W5 & W7 inputs 0 & 6.2v (Green & Black/Green)
100R
R1
100R R4
Parallel Triode 2A3
2A3 Filament 2.5v
W6 & W8 inputs 0 & 6.2v (Black & White)
100R
R3