I am currently building an output stage for a DAC with opamps, in single supply configuration.

Here is my circuit from LTspice:

LTspice schematic

I have exactly built this on PCB, so I am talking about the real thing not the simulation.

Now I am testing this in real life. When I send in a sinus, I can see a perfect sinus on Out_p and on Out_n on my scope, as long as I leave Out_p and Out_n open. But as soon as I connect an audio sink like an audio interface (that I wanted to connect for some measurements), Out_p gets heavily distorted.

So is there something wrong with this circuit?

Any hint is welcome!

  • 2
    \$\begingroup\$ You are either overloading the output of this device or overloading the input of the device you are driving. (1) What are you driving? (2) What is it's input impedance? (3) What is the open-circuit voltage? (4) What is the voltage when you connect the load. Use the edit link below your question to add in the missing details. Don't post them in the comments. \$\endgroup\$ – Transistor Feb 21 at 22:38
  • 2
    \$\begingroup\$ What exactly does "heavily distorted" mean? \$\endgroup\$ – brhans Feb 21 at 22:58
  • \$\begingroup\$ Heavily distorted means that I dont see the Sinus on the scope instead I See something like a burst. \$\endgroup\$ – dacbuilder Feb 21 at 23:10
  • 1
    \$\begingroup\$ @transistor: I will give the details tomorrow when I am working on the circuit again \$\endgroup\$ – dacbuilder Feb 21 at 23:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.