Recently, I started playing arround with some Sallen-Key active filters for my upcoming audio crossover project.
I breadboarded 4th order low pass and high pass filters, with X-over frequency arround 160Hz (100nF caps and 10k resistors), and I used NE5532 opamp.
Power supply is just regular transformer + rectifier + 7815/7915 supply.
Resistors used are Vishay 1% metal film resistors, so they aren't causing issues either.
When connected to my "old" amplifier (Class AB output stages, mains frequency transformer and rectifier, so absolutely no switching circuits) everything seems to work fine and quiet, just as it should be.
However, when I connect that same circuit to my new amp (IRS2092 class D output stages, IR2153 unregulated SMPS), I hear some hissing from my speaker. Not much, maybe 30-ish dB SPL (slightly quieter than standard fan).
Now here is where things get weird - just replacing NE5532 with TL082 more or less completly eliminates that hissing,or at least "pushes" it below hearing level!
I would like to know why is this happening - I understand that TL082 has JFET inputs, and i'm assuming that is what makes this difference.
P.S.
I got same issues when using NE5532 as both non inverting amplifier, and inverting amplifier. For some reason, when I used NE5532 in differential (XLR line receiver) mode, things got quieter.
Since I designed my PCB for SMPS and Class D output stages, it is possible that it's emitting quite a bit of unwanted noise. But still, it's weird that NE5532 is more susceptible to picking up that noise than TL082.