This has been solved.
From your description, I suspect one or more of you amplifying stages is oscillating and adding a high frequency component to the audio signal. Signal tracing with your scope will identify this.
Paul
I figured out the noise source. I was always doing all my test by powering the arduino via usb from my computer. Specifically my usb led keyboard's usb pass through. So the power rail was just super noisy from the start lol The moment I tried running it with a plug pack, everything went away. Also turning off the led lighting on this keyboard (corsair k70) also pretty much fixed the noise issue as well.
USB power from a computer is hopeless for audio, its bursting at the seams with digital hash. Using
a powered USB hub might be cleaner, but in general its just best not to, or to use very good filtering.
And yes, mutiplexed LED displays are a classic source of noise in the audio band.
A typical design for mixed analog/digital board features entirely separate power supplies
and ground for analog and digital, the supplies coupled with back-to-back diodes (normally non-conducting)
to ensure the supplies come up and go down together (if the same voltage). There is one point in the circuit
where the two grounds meet, typically under an ADC or DAC, serving as the notional star-ground point.
You want to avoid any digital supply and ground currents being in the analog supply and ground system,
and you want to keep the sections away from each other (except at the ADC/DAC etc) to reduce
any capacitive coupling. An analog ground screen can over the analog section can be a useful extra
precaution (especially at frequencies above the audio range).
I still need to figure out why the audio output from this op amp is low. The peak to peak voltage is high. So possibly the output current is low? How would I go about increasing that if that is the problem?
The peak to peak voltage is high.
What are you feeding it into?
Is the peak voltage still high when feeding it into what you want?
How would I go about increasing that if that is the problem?
Match the impedance of your output to the device you are driving it into. The details depend on your actual circuit.
The pictures you posted are not in a suitable form because I can't see them without signing up to a load of spam.
This is how to post images here:- Image guide
image guide
First, how do you not have imgur? It's 2018 lol Secondly, I've copy pasted these links into 3 different browsers (IE/Edge, Firefox, and Chrome) in private mode to ensure not being logged in and they pop up just fine without any log in prompts or anything popping up. I'm going to assume you just didn't even try to click on them. This signal is intended to being a line output. I'm just listening to it on a pc capture card. All of this is mentioned in the original post. Please read the whole thing as it has just about any information you could ever want or need to know. All the measurements on the scope are taken under load.
I'm going to assume you just didn't even try to click on them.
You would be wrong there. I clicked on a link and the screen was covered with pop ups wanting me to join and accept cookies and other stuff. I could just see a corner of the picture.
Do not assume every one has your mind set, it is 2018 after all.
This is why we have rules and conventions here on this forum. Have you been arsed to read them? I have read your first post and you have not conveyed enough information for me to know what you have.
So if you can’t be arsed to clarify things why should I be arsed to help you.
Goodbye.
TokyoScarab:
This has been solved.
And now no-one else can benefit.
Please use your forum timeout to read the forum rules and guidelines.