Hello all. I recently finished my first DIY audio project by building a pocket headphone amp by following this page.
The amp works fairly well with good sound. However, there's a rather weird problem. When I plug it into my MPIO FL100 mp3 player (has a metalic casing), there's a noise not unlike when one is tuning an AM radio. This only happens when I touch the MP3 player ONLY. If I touch both, the noise disappears. If I change the source to my Sony Discman (plastic casing), I don't hear such noise. Also, if I change the source to a bookshelf shelf CD player, theres a horrible static noise that drowns out the music. What's going on here? Is this a grounding problem?
The amp works fairly well with good sound. However, there's a rather weird problem. When I plug it into my MPIO FL100 mp3 player (has a metalic casing), there's a noise not unlike when one is tuning an AM radio. This only happens when I touch the MP3 player ONLY. If I touch both, the noise disappears. If I change the source to my Sony Discman (plastic casing), I don't hear such noise. Also, if I change the source to a bookshelf shelf CD player, theres a horrible static noise that drowns out the music. What's going on here? Is this a grounding problem?
Sounds like it could very well be a ground problem. Try touching the casings of both items with a length of wire (insulating yourself from all three) and see if the noise is reduced or eliminated.
I was getting horrendous hum out of a receiver when feeding it audio from my computer (I have a HTPC), but adding equal-length ground straps to all relevant pieces of gear cured it completely - I had some major ground-loop action happening.
oO
I was getting horrendous hum out of a receiver when feeding it audio from my computer (I have a HTPC), but adding equal-length ground straps to all relevant pieces of gear cured it completely - I had some major ground-loop action happening.
oO
make sure your amps input ground is connected to you mini plug ground from your fl100. If it is try adding a 100k resistor from your input pin to the ground of the opa input which should be connected to the mini plug ground from the fl100.
Sounds like a simple differential ground plane issue. make sure all your grounds are the same.
Cheers
Sounds like a simple differential ground plane issue. make sure all your grounds are the same.
Cheers
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