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Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
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In Reply to: Here is another fixed bias amplifier posted by Tre' on August 25, 2023 at 06:47:00:
The Eico HF-87 uses cathode bias. The HF-87 is designed to run the output tubes at almost 75ma. per tube so there is 35 volts across 235 ohms (148.94 ma. of current total for both tubes). Notice there is zero voltage at the grid and no negative supply. The tube gets 100% of it's bias voltage from the cathode resistor.So some tube amplifiers use cathode bias and some tube amplifiers use fixed bias for their output tubes.
It is true that most small signal tubes use cathode bias but you said "All tubes have cathode resistors that provide bias." and that simply is not true. I have clearly shown that.
If you decide to stick around and pay attention, you just might learn something.
Tre'
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Follow Ups
- for contrast here is an amplifier with cathode biased output tubes - Tre' 08/25/2309:25:50 08/25/23 (2)
- He has abandoned ship - Triode_Kingdom 12:05:15 08/26/23 (1)
- Maybe. nt - Tre' 17:04:07 08/26/23 (0)
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