Abstract: The present invention provides a preamplifier, by which it is possible to prevent influence of noise components when there are noise components in power line. There is provided a transformer having a primary winding with a center tap and a secondary winding on output side, and the primary winding of the transformer is connected between plates of two vacuum tubes for performing differential amplification, and positive voltage is applied on the center tap of the primary winding. A switch may be arranged in such manner that input signal and output signal can be separately set to balanced state or unbalanced state.

Abstract: There is provided a tube amplifier comprising a first vacuum tube K3 having a plate applied with a positive voltage and a cathode applied with a negative voltage by a first resistor, a second vacuum tube K4 having a grid connected to the cathode of the first vacuum tube and a cathode or a heater applied with a voltage close to a potential of zero in relation to a plate voltage, and an output transformer TF1 having a first coil and a second coil which is connected to a loud-speaker, said first coil having a terminal connected to the plate of the second vacuum tube and another terminal applied with a positive voltage. Also, time means is used to optimally maintain the grid voltage of the second vacuum tube when the power source is turned on, and the plate voltage of another vacuum tube K1 provided in a preceding stage of the first vacuum tube is controlled to maintain the negative voltage applied to the grid of the second vacuum tube at a desired value.

Abstract: A lubrication boosting additive comprising a mixture of an organic titanium compound soluble in a solvent, an organic solvent for the organic titanium compound, and a phthalic ester. The additive is used in combination with lubricating oils to improve load bearing capacity and wear resistance. When added to lubricating oil, the additive is used in an amount of from 0.1 to 10 g, calculated as the organic titanium compound, per liter of the lubricating oil.

Abstract: A lubrication boosting additive comprising a mixture of a fluororesin, which is an alternating copolymer of a fluoroolefin and vinyl ether, soluble in an organic solvent and a phthalic ester in an organic solvent. The amounts of the organic solvent and the phthalic acid are, respectively, from 50 to 500 parts by weight and from 1 to 50 parts by weight per 100 parts by weight of the fluororesin. The additive is added to lubricating oils in an amount of from 0.1 to 10 g, calculated as the fluororesin, per liter of the lubricating oil.