It sounds a bit extreme, although Patrick Turner claims to have been using it at 375V B+. An LTSpice static DC simulation of 375V B+ and 60mA anode current gives a current of 3.6mA running through g2 with a 200R resistor in series. It's a robust tube, but even if there won't be enough g2 current to cause a meltdown in triode mode, what about the g2 to g1 distance and potential arcing, especially when g2 swings with the anode to the other extreme, like 750V peak?
Best regards,
Alexander.
Best regards,
Alexander.
It is very doubtful that it will run right at 375V without excessive G2 current / possible runaway and massive negative G1 bias = large voltage drive
I just ran it off in static mode. At 380V B+ and 55mA Idc in triode mode, I'm measuring 5uA (0.5V) across 1k g2 resistor. 🙂
Meant 500uA, sorry!
By the way, there are variation of g2 currents between different manufacturers. A PL36 Matsushita scorew with 4.5mA of g2 current, which is more realistic.
By the way, there are variation of g2 currents between different manufacturers. A PL36 Matsushita scorew with 4.5mA of g2 current, which is more realistic.
This variation between different manufacturors reflects much of what Geaorge from Tubelab describes when he is investigating the limits of tube types. Ultimately the tubes must be capable of matching the requirements of the tube data, but in reality some types may well exceed those requirements.
The problem is that if one is to go to the effort to implement an amplifier around one tube type, then I think it has to be tolerant to all brands of tubes that could be fitted to it, with the same tube type, new and old.
I really enjoy reading Patrick Turner's thoughts, and he is a very defensive solution developer, so it does not seem to be possible that a PL36 or EL36 would not work in a circuit that he is describing. The only possible issue is that they are using Australian sourced tubes, and maybe they were tougher than some of the ones we have in Europe?
What is the g2 dissipation of the Matsushita tube?
The problem is that if one is to go to the effort to implement an amplifier around one tube type, then I think it has to be tolerant to all brands of tubes that could be fitted to it, with the same tube type, new and old.
I really enjoy reading Patrick Turner's thoughts, and he is a very defensive solution developer, so it does not seem to be possible that a PL36 or EL36 would not work in a circuit that he is describing. The only possible issue is that they are using Australian sourced tubes, and maybe they were tougher than some of the ones we have in Europe?
What is the g2 dissipation of the Matsushita tube?