OK, the next tube was not allergic to water and behaved normally: with just the heather, the current is 298.9mA, and 296.2mA with 15W dissipation, a ratio of 1.00911, a 0.911% increase in resistance.
It is thus very marginally better than with the heatsink, but 15W is still excessive.
The test was made with still water (it was already complicated enough without pipes, pumps, etc!)
It is thus very marginally better than with the heatsink, but 15W is still excessive.
The test was made with still water (it was already complicated enough without pipes, pumps, etc!)
6L6 Heater vs 7R Resistor
In general tube operating heater resistance runs about 10X of the cold resistance. So here for the curious & others is what the heater in a 6L6 looks like on that basis when compared to a 7R resistance. The incremental resistance at the operating point looks like ~12.5R.
In general tube operating heater resistance runs about 10X of the cold resistance. So here for the curious & others is what the heater in a 6L6 looks like on that basis when compared to a 7R resistance. The incremental resistance at the operating point looks like ~12.5R.
Yes, the filament resistance is heavily non-linear.
Something interesting to evaluate would be the cooling effect of electron emission: the 12°C additional heating caused by the anode dissipation is clearly underestimated.
The anode temperature must rise by 100~200°C at least, and the cathode is completely enclosed in the anode.
For comparisons like here, the absolute figures do not matter very much, but knowing them would be interesting
Something interesting to evaluate would be the cooling effect of electron emission: the 12°C additional heating caused by the anode dissipation is clearly underestimated.
The anode temperature must rise by 100~200°C at least, and the cathode is completely enclosed in the anode.
For comparisons like here, the absolute figures do not matter very much, but knowing them would be interesting
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