In some clubs I get a bad hum (60 cycle?) from neon lights but not in other clubs. The hum gets better or worse by moving around, but never goeas away. I have a hum eliminator which works for ground loop hum but not for this. I'm using Seymour Duncan Humbuckers so thats not the problem. Can parametric EQ be used to isolate this frequency and if so, how? Thanks for your help...
You can filter out a lot of it with EQ.
First figure out where its getting in (between guitar and amp, FX loop, pedal chain, etc)
Then put an EQ between the place it is showing up and the next hop in the chain.
Set it to 60Hz, gain as low as it'll go, Q as narrow as it will go.
bring the gain back in until the hum bothers you, then back it off a bit.
If you find that EQing 60Hz makes little or no difference, try it at the harmonic frequencies of 60Hz - 120, 180, 240, etc.