Sorry you have right , I calculate ( in a hurry ) the current across the R119 405V-345V / 10K =6mA
I "forgot " the other stage ( V101 102 )
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Thanks guys, I'm willing to give these a shot. One other question, the 10 ohm restistors on the el34's are 5% tolerance (J rated), I measured them on each valve and they are not equal values. I've read it's pretty important to have these equal so the balance will be proper. Is this something that I should rectify?
The 10 ohm resistors it's better to be equal to help you to set the current of each output tube easier , I mean if you have equals resistors and the same voltage drop on each one then the currents will be equals .
This is important because if you put a voltmeter on the two anodes of the tubes the measured voltage should be zero , otherwise ( for example if you measure 1 or 2 volts ) there is a risk of saturation in the output transformer .
This is important because if you put a voltmeter on the two anodes of the tubes the measured voltage should be zero , otherwise ( for example if you measure 1 or 2 volts ) there is a risk of saturation in the output transformer .
How closely matched must the resistors be to give acceptable balance when adjusting the valves? For example, in the right side, one gives a reading of 10.4 ohms, the other 9.9 ohms. I'm thinking this isn't good enough. Isn't there a danger of magnetizing the OPT's core if the tube currents are different?
You can leave the 10Ω resistors as they are , and set the voltage on them for example 0.3V ( 0.3V / 10ohm = 30mA attention this is only an example ) using the RP101 and RP102 and then measure the voltage on the two anodes , if it's not zero then " re- tune " one of the RP101- RP102 to make the voltage zero .
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