Rolph,
there are two ways to reduce the voltage. One is with a resister With a resistor, the voltage drop varies with the current used. The vendors sell a large resistor for the heater or the radio which will do the job. However, if something fails in the radio, such as the rectifier OZ4 tube, a large part of the load will disappear and the voltage on the radio will go up. In this case, leaving the radio on after it fails to operate could subject all the rest of the tubes to a higher heater voltage.
Another way to reduce the voltage is with a three terminal regulator. This is a circuit that uses a solid state regulator. It is powered at 12 volts and it has a third lead that powers the radio at 6 volts. There is a device by Runtz that does this. There is also a thread in this forum showing plans for a do it yourself circuit to do this.
Fred
Last edited by truckernix; 04/18/2010 11:45 AM.
