3 ms·

Did you put one of the diodes in the feedback loop to linearize them ?

• amelius 4y ago
  Feedback is frowned upon in audiophile circles: https://www.audioholics.com/audio-amplifier/amp-myths-negative-feedback https://www.audioholics.com/audio-amplifier/amp-myths-negati...
  • buescher 4y ago
    It depends on the audiophile circle, but yes. There's a circle of folks that swear by single-ended triodes, class A operation, no feedback. I would love to hear a setup like that, but I haven't bought one (yet?), so I won't comment until I do.
  • xani_ 4y ago
    You mean audiophool circles
• MisterTea 4y ago
  Yes but there were still linearity issues. The senior engineer played with it for a bit until he said screw it, spend the money and be done. Project was small enough to justify the cost.
  • xani_ 4y ago
    Do you remember numbers ? I'd guess somewhere in 0.5-1% THD range for simple single opamp servo ? I was kinda mildly interested into doing it for sensors altho just microprocessor blasting serial via optocoupler onto other side seems like easier solution... Their application note (page 9) details circuits most audio people would just look at it and go "screw it, i will just buy audio transformer like rest of us" https://www.vishay.com/docs/83708/appnote50.pdf https://www.vishay.com/docs/83708/appnote50.pdf I don't doubt they achieved the claimed values but the circuit to do it had 4 precision opamps (bipolar one have 7) and a bunch of other components so I'm not surprised he didn't want to bother
    • MisterTea 4y ago
      Sorry, cant remember specifics. But if I were doing this again, today, I'd use an isolated serial ADC. I had a lot of fun with analog stuff but fixing signal issues in code is easier than solder.