While an EQ can be used to filter out noise, it can become impractical. For example, when you have noise that also has its harmonic frequencies present (60Hz, 120Hz, etc). I personally prefer to use EQ for tone shaping rather than noise management.
There are other solution for managing noise. I posted the following in another thread and copied it over here:
When you have a hum or buzz that is eliminated or affected by touching a metal part of the guitar, this is most likely caused by a grounding issue.
The remaining hum could come for several sources:
- Single coil pickups will by their very nature pickup 60Hz hum (And
it’s harmonics). This is a type of inducted noise.
- Electical noise from dimmers, fluorescent lights, A/Cs and
compressors (just to name a few sources) as well as RF frequencies in
the environment are another type of inducted noise that pickups or
tube amps can receive and inject into your tone chain
- The higher your gain setting, the more sensitive your rig becomes to
inducted noise. Even humbuckers will pick up inductive noise
especially under very high gain scenarios.
- Conducted noise sources include things like ground loops, noise that
enters the system trough a noisy power source and noise added by
components in your signal chain
Using a multi-meter with a continuity test function you should be able to easily track down any grounding problem within the guitar itself.
As for the rest of the noise, this is tougher.
First, if a guitar is not shielded, noise can enter through the pickups as well as the wiring, pots and switches in the control cavity. Your guitar is essentially a giant electromagnetic antennae. Shielding the control cavity can provide a good amount of noise reduction. Shielding pickup cavities can provide a small amount of reduction but is far less impactful than shielding the control cavity. If the only wire in your tremolo cavity is a ground wire, shielding the tremolo cavity will have no effect. ALL SHIELDING MUST HAVE CONTINUITY TO GROUND IN ORDER FOR THE SHIELDING TO WORK.
Next, getting a good noise suppressor will help. Note I said suppressor not gate. There is a difference. Noise suppressors include both a gate and a filter whereas a noise gate only includes the gate. A good 2 connection suppressor will take a lot of inducted noise out of your tone. Examples of good noise suppressor include the Boss NS2 and my personal favorite the ISP Decimator G String. The only Decimator you want is one of the G series... either G string for a pedal or Pro Rack G for rack. You need to go through the noise suppressor to your amp input, then connect it into your amps effect loop. This will make a big difference in the inducted noise in your signal.
Next for conducted noise get a good power conditioner for your effects and peripherals. You should not connect your amp to a power conditioner. Modern amps use variable power consumption which a power conditioner may have problems with. For the amp, there are ground isolators like the HummX or one made by Logsdon (cannot remember the name). If you want to go really crazy there are isolation transformers like those used for sensitive medical equipment. These are expensive and heavy.
Never, ever use a ground lift as a permanent solution to grounding problems! You are playing Russian Roulette if you do. Ground lifts are fine for diagnosing problems, but they are not a permanent solution!