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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?

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    \$\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 '17 at 4:13
  • \$\begingroup\$ Opamp: puu.sh/y8eEZ/440eee05d5.png Input and output waves: puu.sh/y8eGI/20e8bee27e.png \$\endgroup\$ – dos584 Oct 27 '17 at 5:36
  • \$\begingroup\$ Have you ever heard of "audio amplifiers"? \$\endgroup\$ – Ale..chenski Oct 27 '17 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 '17 at 6:06
  • \$\begingroup\$ Relevant: kepcopower.com/nomoslew.htm \$\endgroup\$ – RJR Oct 27 '17 at 6:43
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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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