Valve Circuits 5

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1. Regulated Power Supply

The circuit to the right will provide 300v regulated at up to 200mA as long as there is sufficient cooling for the 6080 series control valve - see below and the total dissipation (26W) is not exceeded. If in doubt two 6080 valves may be used in parallel.

Note that separate and well insulated heater supplies must be provided for the 12AX7 and 6080 valves as the heater cathode insulation is inadequate for common supplies.

A well smoothed 440V supply is required and bleed resistors should be placed across any large value capacitors.

The 1u loop stabilising capacitor should be low leakage.

As the SB600 enclosure was fairly densely packed a miniature 12v DC fan and thermostatic controller was installed to move air around the 6080 regulator. The mains transformer for this regulator also included windings for the various regulator heaters together with 12.6v 6.5A, 750v 250mA and 150v 50mA for a negative bias supply. The composite power supply may be used with an SB-101 transceiver etc.