Usually on the frequency response of an open loop op amp, the gain decrease greatly in the higher frequencies. How can we increase the gain from 50 hz to 25 khz to remain high at, say, 120 dB?

The reason is I want to make a noise generator as an additional sound effect after seeing some circuit bend pedals on several electric guitar effect-related forums.

  • \$\begingroup\$ wait, is this about an open-loop opamp circuit configuration, or about the opamp in itself? I.e., do you want to take a fixed opamp and have it in a higher-bandwidth circuit, or are you designing an opamp for the purpose of this question? \$\endgroup\$ Oct 6, 2022 at 7:00
  • \$\begingroup\$ It is the former. But you bring in about the opamp in itself, is it possible to do the same to the opamp itself? \$\endgroup\$
    – SnoopyKid
    Oct 6, 2022 at 7:03
  • \$\begingroup\$ you will have to. Because if your circuit is open-loop, there's nothing you can do to increase gain beyond what the opamp in itself can do. \$\endgroup\$ Oct 6, 2022 at 7:07
  • \$\begingroup\$ So what are the possible ways to increase the gain of frequencies from 50 hz to 25 khz with an opamp with a very high open loop gain of 150 dB? If we can't do that with an open loop circuit, then what should we do? Using different op amps? \$\endgroup\$
    – SnoopyKid
    Oct 6, 2022 at 7:12
  • 2
    \$\begingroup\$ you can't change the open loop response of an IC opamp. It is what it is. You reduce its gain using feedback and tailor the FB network to shape the closed loop response. (Some opamps have a compensation terminal, in that case you need to look at the datasheet to see what it does.) \$\endgroup\$
    – danmcb
    Oct 6, 2022 at 7:42


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