Hi Folks,

I am fixing a old Class A amplifier based on German ium transistors, and the lower output transistor is blown. I only have a silicone replacement and I know that the BE junction voltage is closer to 0.6-0.7V compared to Germans at about 0.3-0.4V, so there's a 0.3V-ish difference.

To compensate, I am proposing to 'jack up' the base voltage of the silicone transistor by using 8 x 2.2V precision Zen diodes as in the revised schematic here. I am using a bank of Zens in parallel for voltage accuracy, and I understand that 8 in parallel will give me a bias voltage of 2.2/8 = 0.375V. Because I don't want the DC offset to affect the signal, I will be adding DC blocking capacitors as shown too - something like 1F each, maybe?.

Will this work, or am I overthinking things and should I just use a single, adjustable buck converter set to about 0.3V?

Thanks!

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https://preview.redd.it/5ireaq7kwuac1.png?width=528&format=png&auto=webp&s=7bd111b5c85f94c3a42442e0535bf029e72344ca