New-Old-Stock (NOS) tube.

The 5670 is a miniature medium-mu twin triode each section of which as a separate cathode connection. The tube is suited for use in a wide variety of general-purpose amplifier and mixer circuits as well as numerous multi-vibrator and oscillator applications. The useful operating range extends from low frequencies through the VHF region.

The 5670 is a special-quality tube intended for use in critical industrial and military applications in which operational dependability is of primary importance. Features of the tube include a high degree of mechanical strength and a heater-cathode construction capable of withstanding many-thousand cycles of intermittent operation. When used in on-off control applications, the tube will maintain its emission capabilities after long periods of operation under cutoff conditions. Analysis of the electrical characteristics of this tube with those of the 2C51 will indicate that the 5670 is essentially similar.