metrix: U61 (U 61); Modfication for linear filament vol

Hello, from our french speaking friend jacques Dudoret, we got proposal how to modify the Metrix U61 tube analyzer for linear filament voltage readout using an operations amplifier circuit.
I hope, our english language tube analyzer specialists will understand the circuits without translation...

Modification for linear filament voltage readout
Hope that helps, kind regards Martin Boesch

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