Grounding Rod in basement?
If you get hum in audio electronics, it's almost certainly not the result of a poor electrical system ground. In fact, if your electrical system grounding conductors were all well-bonded but not grounded at all, your stereo would still be perfectly happy. 

There are several much more likely potential sources for hum, mostly due to defective power supply filtering capacitors or power supply decoupling capacitors, "ground loops", capacitive, inductive, or common impedance coupling. Unfortunately, isolating the cause and curing it can be an adventure in debugging and diagnosis.

Older audio gear may have electrolytic or tantalum capacitors that have aged and dried out, or they may simply have failed, which reduces their capacitance and increases 60 Hz or 120Hz ripple in an audio component's power supply, causing increased hum. If your power amplifier or receiver creates hum in your speakers all by itself with no inputs attached or the input selector on an unused input, this can be the cause.

Ground loops are created when there is more than one ground path from device A to device B. The multiple paths form a loop, topologically speaking, hence the name. A ground loop is like a 1-turn transformer, and can couple stray magnetic fields from power conductors (or power transformers) at the 60Hz AC power frequency, which then results in a 60Hz current and voltage induced around the ground loop, which can impress itself on the "ground" of the unbalanced signal inputs in one of the devices, which you hear as hum. Ground loops can be difficult to deal with. Unplugging audio cables until the hum ceases, then replugging them one by one can point to a culprit ground loop.

Inductive (or magnetic field) coupling can occur between the magnetic fields of large power transformers (usually found in high power amplifiers) and sensitive magnetic devices like phonograph cartridges, magnetic tape heads, etc. This is why expensive audio gear will often have toroidal power transformers, which result in less stray magnetic fields and less likelihood of magnetic coupling.

Capacitive (or electric field) coupling can occur between high voltage waveforms (like 120V power line) and high impedance signal nodes (like the inputs of preamplifiers and even power amplifiers). 

Capacitive and magnetic coupling is the reason quality electronics is packaged in metallic packages: a metallic conductive enclosure will act to prevent electric and magnetic fields from entering the enclosure (the Faraday effect)  causing undesired coupling to sensitive signals. You can easily diagnose electric and magnetic coupling by physically separating audio components. The hum will decrease with increased separation.

Common impedance coupling occurs when an interfering signal (like AC power currents) flow in an impedance shared with another signal circuit, perhaps because of a small-gauge or poorly manufactured powerbar power cord shared by a large power amplifier and a preamplifier. Connecting large power amplifiers on their own circuit, or with their own large-gauge power cord into a different receptacle on the same circuit can benefit an audio installation suffering from common impedance coupling. Making sure the receptacle powering your audio equipment is the first on a circuit run from the electrical panel, and that the run is as short as possible, and no other appliances are on this circuit can also help.

Finally, making sure that the audio cables connecting your audio components are high quality, with good ground shield coverage, can minimize inductive and capacitive coupling to the signal conductors. Make sure that the connectors make good "ground" contact and are not oxidized or corroded (that's why the better ones are gold plated), so that the cable shields can be effective.

Whew. That's a long answer, and my fingers are cramping up. Hope it helps.