Tube DIY Asylum

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It's Even Worse than What I Posted...

Posted by Triode_Kingdom on June 13, 2021 at 18:59:43:
I left one thing out of the original post because it's so confusing. As I said, Rozenblit stated that the only way the circuit can work is when the currents through both tubes are unequal by a small amount. It needs to be pointed out that he's not talking about some molecular-level minutiae. Here's the next thing he says:

"The only way to make the currents unequal is to make RL1 and RL2 unequal. The required difference is on the order of 10-20%, with RL2 always the larger of the two."

This statement (plus his previous assertion) tells me he has totally failed to grasp the operation of the circuit. The need to make the resistors unequal is of course because we need to convert the unequal currents to balanced differential output voltages. But the unequal currents aren't necessary to the function of the circuit, they're a detrimental side effect of using a resistor in the tail while driving one triode at its grid and the other at its cathode.

One thing interesting about all this is that Broskie has referred to Rozenblit's work in several places within TubeCad. I do wonder if they're working off a shared misconception in this one area.