Floating ground in the apt. Building


i live in a common NYC postwar apt.building (270 units)

i changed several during my life in NYC and was always floating ground on the breaker side. Connecting the ground always resulted in the system being dark, bassy, constricted. Lifting the ground always brought back the air and widened the soundstage. The building I currently live in had the crappiest breaker panel I have ever encountered so I decided to connect the ground just in case. The ground wire in my cryo’d romex spool was cut shorter from not being used and I needed a jumper of sorts to connect it to the ground terminal. I didn’t have any 10 gauge wire on hand so I temporarily used a 5 inch piece of regular extension cord. The sound became fuller in the midbass region but did not lose any air. Now I went out and bought a piece of 10 gauge romex and after connecting it the soundstage collapsed and the sound became dull again. I reconnected the cheap multi strand piece of extension cord and everything is nice again.
I have 2 questions:

1. I heard or read somewhere that you don’t have to ground equipment in big apt. buildings since they are already grounded. All existing outlets on other breaker lines in my apt. are 3 prong but do not have a grounding wire running attached to them.
2. Have anybody experimented with different gauges and materials like silver when it comes to grounding? In my case, the cheap extension cord piece is a clear winner over 10 awg Romex but it left me curious of what else is out there I can try.
sorry if my post is kinda jumbled and confusing.
any feedback and experiences would be appreciated.


Can ground wire be a smaller gauge?

The neutral wire should be the same size as the hot wire - but the ground wire can be smaller. Normally, the ground wire carries zero current. In the event of a short (the only reason for a ground wire), it only has to carry current long enough to trip the breaker - which isn't long enough for the wire to get very hot.

If the building uses 3-prong outlets that screw into metal boxes, then the entire system is grounded since the metal conduits all connect back to the panel(s) and ultimately, the building ground.

You have a romex spool with the ground wire too short? What does this have to do with the wiring already in the wall? Unless...

Did you take that romex spool to your new apartment and then connected to a new outlet you installed and then ran the wire (exposed!?) to the breaker panel and found out the grounding conductor is too short?

I bought that spool from VH Audio 20 years ago and cut the ground wire by 5 inches because I always floated the ground. 
yes, all outlets are in metal boxes. 
my line is an outside line with external 1 gang outlet metal box. 
my power distribution is Furutech. 

It is possible to create a Ground Reference if you're the AC source. It's possible have a transformer between House AC your new AC going through a transformer. However you transformer now become you AC and your reference you will need a larger transformer and your wiring taken to the low side of. Of course a little electrical smarts will help.