[ms660]

As I understand it from previous posts your mains voltage is around 245 volts and the receiver is set for 220 volts, if that's the case you need to drop the difference which is 25 volts, you can do that by connecting a resistor in series with R37.

Both the heater current and the rectifier current will flow through the resistor, use the heater current given in the valve data sheets and add that to the rectifier current, for a ball park figure for the rectifier current assume that it's 2.2 times greater than the DC load current.

The heater current given in the valve data sheets is 0.1 amps, the DC load current can be worked out by adding up the anode and screen grid currents given in the table in the manual or alternatively it can be found using Ohms law by dividing the voltage given across C75 in the manual by the resistance of R75 which equates to 8.2 (volts) divided by 121 (ohms) which equals approx. 0.068 (amps) Multiplying that by 2.2 equals approx. 0.150 amps, adding that to a heater current of 0.1 amps equals 0.25 amps....

Now do the Ohms law for the ball park resistor value which is 25 (volts) divided by 0.25 (amps) which equals 100 (ohms)

The power dissipated by the resistor will be the voltage across it multiplied by the current flowing through it....25 (volts) multiplied by 0.25 (amps) which equals 6.25 (watts) so use one rated at 10 watts for a happy resistor life.

Lawrence.