I built two circuits as similarly as possible 1) quad ua741 and dual NE5532. FFT on my Rigol scope showing peaks at 1k and 15k as set/expected (2 channels from Seesil generator are mixed with 1k signal at 80% of 15k signal amplitude) with this I believe I created a tool to do AM with my cheap Seesil generator and can also mix two audio signals.

That said, I have no clue what I am doing. I based my testing procedure off an Elenco radio kit.

So I guess I actually have two questions or areas where I am trying to understand better:

  1. What makes one op-amp better than another? I am talking about the IC itself, I believe. Why is NE5532 better than ua741, I see and hear the difference, now why?

  2. What should I be testing and/or what data should I be collecting to better understand and characterized?

Thank you for your time and consideration. I am 100% self-taught savage from the wilderness and stumbled into your camp, but we are not so different, I promise, just had to walk down different road in life. Thanks again.

  • Sadbutdru@sopuli.xyzEnglish
    5·
    22 days ago

    Someone more knowledgeable than me will likely join in soon, but depending on your application one op amp might be better than another because of

    • higher slew rate (which affects max frequency)

    • higher unity gain bandwidth (if you need to amplify a wide range on frequencies)

    • better common mode rejection ratio (for working with small signals and electrically noisy environments)

    • lower input bias current (for low- power applications)

    • higher input/ lower output impedance (to not load sensitive instruments/ distort signals)

    And probably loads of other things… cost… thermal…

    • basketugly@lemmy.worldOPEnglish
      4·
      22 days ago

      Thank you, perhaps it is the CMRR that I need to explore? Perhaps this explains the noise floor difference? Thank you.