Re: Another Advance E2 Signal Generator.
Advance E2.
The 6X5 rectifier is rated for operation with the other heater supplies, the heater cathode insulation rating allows 450V heater to cathode. So that is perfectly satisfactory.
The reservoir capacitance quoted by the valve makers (RCA) is 10uf, assuming a reasonable transformer winding resistance.
The limiting factor is the peak charging current. Here the valve is operating so very well within its maximum ratings that you don't need to worry.
The revised smoothing capacitors were maybe what was in the spares box when they were fitted. I get the impression that the previous owner was worried about hum, and so had an exceptionally smooth HT supply.
With a 64uf reservoir capacitor, a series resistor of 22 ohm sounds a bit low, unless the resistance of the transformer HT windings are higher than usual. If you are concerned, why not put back the 560ohm. The anode current is so low that it will hardly affect the HT rail voltage as the oscillator only operates anyway on 120 - 150v.
wme_bill
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