I'm trying to amplify a sine wave voltage signal by two at high frequencies (20kHz) I've tried using an op-amp as the frequency gets this high the wave turns triangular (I'm assuming this is to do with the slew rate).

Is there another way to amplify this signal across the frequencies of 1-20kHz and keep the sine wave?

  • 2
    \$\begingroup\$ Post schematics and the scope output if possible. 20kHz shouldn't be a problem. You did not mention the voltage of your output. \$\endgroup\$
    – Wesley Lee
    Oct 27, 2017 at 4:13
  • \$\begingroup\$ Opamp: puu.sh/y8eEZ/440eee05d5.png Input and output waves: puu.sh/y8eGI/20e8bee27e.png \$\endgroup\$
    – dos584
    Oct 27, 2017 at 5:36
  • \$\begingroup\$ Have you ever heard of "audio amplifiers"? \$\endgroup\$ Oct 27, 2017 at 5:40
  • \$\begingroup\$ If you use an op-amp with a higher specified slew rate, then it will work better. Hint, almost any op-amp is faster than a 741. \$\endgroup\$
    – Neil_UK
    Oct 27, 2017 at 6:06
  • \$\begingroup\$ Relevant: kepcopower.com/nomoslew.htm \$\endgroup\$
    – RJR
    Oct 27, 2017 at 6:43

1 Answer 1


A 741 op-amp has a very low slew rate, 0.5V/uS if I recall correctly.

Something like a TLO71/2/4 at 13V/uS would be far better if you want to stick with old and low cost common op-amps, or an OP275 at 22V/uS is aimed at the pro-audio market.

In fact, almost any op-amp that isn't billed as 'micropower' will out slew a 741.


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