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US 5,550,509 AGranted
Output power selection apparatus for a tube-type audio amplifier
OwnerSalvatore J. Trentinoinventor
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Abstract
An output power selection apparatus reduces the R.M.S. power output of a tube type amplifier without the use of solid state devices or ganged high or low power potentiometers.
Claims3
An output power selection apparatus for a tube-type audio amplifier, said apparatus comprising:
- an output tube having a screen grid and a control grid;
- a screen grid voltage supply;
- a control grid bias supply;
- and
- a power reduction switch selectively connecting said output tube screen grid directly to the screen grid voltage supply through a current limiting resistor, and connecting said output tube control grid to the control grid bias supply whose potential voltage is at the more negative of two selectable voltage level values for high power operation, and connecting said output tube screen grid to the screen grid power supply through a power limiting resistor connected to said current limiting resistor, and the output tube control grid to the less negative of two selectable voltage levels for low power operation.
2 more elements
Dependencies are inferred from the claim text.