Vacuum Tube Breadboard Project

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.

Vacuum tube breadboard power supply

Power supply
T1 6K1VF from Allied Electronics
L1 Triad part number C-3X

Vacuum tube breadboard main chassis

Chassis drilled,
later painted white

Vacuum tube breadboard main chassis

Inside before wiring

Vacuum tube breadboard main chassis

Push-in connector
Female to female jumper
One end gets cut off

Vacuum tube breadboard main chassis

Push-in connectors glued in grommets

Vacuum tube breadboard main chassis

Inside wired

Vacuum tube breadboard completed

The completed breadboard

The meters and breadboard jumper wires were purchased from 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.

DISCLAIMER assumes no responsibility for damage, injury or otherwise related to any use of information on this site or given by other means. Many electronic circuits, in particular vacuum tube circuits, operate with dangerous voltage and current. Always excercise care when working with circuits.

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