New Variable-Mu Valve

Radio Record, Volume IV, Issue 44, 15 May 1931, Page 36

New Variable-Mu Valve

"A T:a recent meeting of the Institute of Radio HDngineers, a new principle in screen-grid valve design was announced, according to George Lewis, vice-president of the Arcturus Radio Tube Company, Newark, NJ., and chairman of the Vacuum Tube Committee of R.M.A. . "This new valve, known as the type 551 variable-mu tube, bears promise of having a wide and useful application in radio set design in the near future," says Mr. Lewis. "The type 551 operates on the vari-able-mu principle, wherein cross-talk and modulation distortion, caused by high-powered local stations, is practically ‘minated. It is built to handle a signal 25 times greater than presentday screen-grid valves, which means smooth, even volume in reception at all times. "This new valve,’ says Mr. Lewis, ‘not only makes possible a vast improvement in the operating efficiency of a radio set, but permits certain advantages and simplifications in the circuit arrangement. I believe that ‘his is the most versatile valve development in a good many years."