The breadboard is primarily for use with pre-amp experiments. High voltage supply is limited to 25 mA and filament maximum current is 1 AMP. A switch in the transformer high voltage center tap allows switching between 180VDC or 360VDC. Adjustable bias is provided for fixed bias circuits. There are two tube sockets, one 9-pin miniature and one 8-pin octal.
T1 6K1VF from Allied Electronics
L1 Triad part number C-3X
later painted white
Inside before wiring
Female to female jumper
One end gets cut off
Push-in connectors glued in grommets
The completed breadboard
The meters and breadboard jumper wires were purchased from allelectronics.com. The X10 range switch puts a resistor in series with the 100VDC meter for 1000 volts full scale. Value of the resistor depends on resistance of meter, for the meter used the value was 910K ohms. The high scale was needed to read voltages over 100V, the X1 low scale when voltage at a tubes' plate is below 100 volts.
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