I've finished building an amplifier for myself using the amp IC from a car stereo. I copied the circuit from the stereo with a few adjustments to make it work on the output from my computers soundcard.
It amplifies, and doesn't sound bad at high volume - since that is when the music from my computer properly drowns out the static type noise coming from the speakers. It's there when the amp is connected to the computer's soundcard. Disconnect it and it has the very quiet hum typical of amps. Connect it to my digital voice recorder headphone output and it's fine. Back in the computer and even before the computer is making any sound and with the amp volume control set to lowest, there's this noise which stays about the same no matter what the volume pot is set to.
The volume pot lets none of my music from the computer through when in the lowest setting, so this hum is separate and loud and annoying.
From what I can tell, it's on the ground side of the computer. If I disconnect the ground from the volume pot on the amp, the noise is much reduced, but I then have no proper control of the volume if I get the computer to play some music. Course, can't connect the input ground, although that'd solve the prob, no doubt.
So the computer ground is making this noise. What can or should I do? The amp shares the same ground, with input grounds going straight to the amp ground, which is also the power input ground, and so on.
Is there a way to clean the ground signal or something?
Many thankitos,
James
It amplifies, and doesn't sound bad at high volume - since that is when the music from my computer properly drowns out the static type noise coming from the speakers. It's there when the amp is connected to the computer's soundcard. Disconnect it and it has the very quiet hum typical of amps. Connect it to my digital voice recorder headphone output and it's fine. Back in the computer and even before the computer is making any sound and with the amp volume control set to lowest, there's this noise which stays about the same no matter what the volume pot is set to.
The volume pot lets none of my music from the computer through when in the lowest setting, so this hum is separate and loud and annoying.
From what I can tell, it's on the ground side of the computer. If I disconnect the ground from the volume pot on the amp, the noise is much reduced, but I then have no proper control of the volume if I get the computer to play some music. Course, can't connect the input ground, although that'd solve the prob, no doubt.
So the computer ground is making this noise. What can or should I do? The amp shares the same ground, with input grounds going straight to the amp ground, which is also the power input ground, and so on.
Is there a way to clean the ground signal or something?
Many thankitos,
James
