AZ41 (AZ41) pin assignment

I have just read the "warning" about pin assignment of this tube.

I have a couple of tubes both manufactured by Philips.

In the first tube, maybe older, pins 1 and 5 are connected to the tension spring of the filament, pins 3 and 4 are connected to the center of the filaments.

In the second tube, pins 1 and 2 are connected to one anode, pins 5 and 6 to the other, and 3 and 4 again to the center of the filament.

I have only one radio that employs this tube, but in case of replacement I need extra care to check the socket connections to avoid problems.

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