I have a simple audio circuit which when I power from a power pack (5V DC) works fine. If I connect to a USB power supply (literally only supply + & - connected going to the same supply inputs) all hell breaks loose audio wise.
The circuit is isolated from the soundcard bias in both cases with a 470nF electrolytic cap.
Is there a simple way to clean this supply up or is it simpler to use a battery supply and keep it "clean" from the USB supply? To my simple mind, a USB DC supply is just +-5V DC but I guwss I'm mistaken.
Sorry for being a tad simple in advance - I thought I had a nice clean audio until now.
Here's the sound... (no pic cos I couldn't be bothered to plug in a camera).
Sound Example
The circuit is isolated from the soundcard bias in both cases with a 470nF electrolytic cap.
Is there a simple way to clean this supply up or is it simpler to use a battery supply and keep it "clean" from the USB supply? To my simple mind, a USB DC supply is just +-5V DC but I guwss I'm mistaken.
Sorry for being a tad simple in advance - I thought I had a nice clean audio until now.
Here's the sound... (no pic cos I couldn't be bothered to plug in a camera).
Sound Example