Hello to everyone.
I've got some noise problems with a headphone amp and I'm not shure how to fix. The schematic is attached. The HP amp is driven directly by the output of another NE5532A (not shown in the schematic).
I have noise problems with some digital signals from the rest of the circuit which I can hear through the phones. The strange thing is, that the noise disappears when I touch the input pin by hand.
A 100k resistor or a 100nF-10µF capacitor connected from input pin to GNDA doesn't help. The signal GNDA is NOT connected to mains earth/chassis.
Can anyone give me a hint how to suppress that noise?
Thanx in advance!
KMT
I've got some noise problems with a headphone amp and I'm not shure how to fix. The schematic is attached. The HP amp is driven directly by the output of another NE5532A (not shown in the schematic).
I have noise problems with some digital signals from the rest of the circuit which I can hear through the phones. The strange thing is, that the noise disappears when I touch the input pin by hand.
A 100k resistor or a 100nF-10µF capacitor connected from input pin to GNDA doesn't help. The signal GNDA is NOT connected to mains earth/chassis.
Can anyone give me a hint how to suppress that noise?
Thanx in advance!
KMT
Attachments
Make sure you have bypass capacitors between the +15 rail and ground and between the -15 rail and ground. Try .1uf.
One of the chips may be oscillating.
You may want to insert a low value <100 ohm resistor on the output of the BUF534. Put it in series with the output before the R4 feedback resistor.
One of the chips may be oscillating.
You may want to insert a low value <100 ohm resistor on the output of the BUF534. Put it in series with the output before the R4 feedback resistor.
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