Upgrading wall outlets

I just added two 20 amp circuits for my power amps using 10gauge with ground wire. I used Leviton 20A Heavy Duty Outlets. The difference is large. I have blacker back ground and smoother definition. I am also taking all appliances off the electric grid moving them to gas. This will create less demand for amps and to allow my stereo dedicated circuits to breathe more freely.

I have a question about using 30 amp breakers. There are people using 30 amp breakers for there 10 gauge wire and 110 circuits. The only way I know to use a 30 amp breaker and meet code is to use 3 wire instead of 2 and install a 4 plex so each side of the 4 plex is 15 amps. Is there another way to meet code and use a 30 amp breaker? IF you were only going to plug a big amp in would a 20 amp breaker be preferred?

Thanks for showing me the High Magnetic breakers. It turns out I am using square D as shown. I am thinking of buying a pair of Bryston 28SST amps. I probably will replace my breakers then.
The Leviton receptacle does have a supporting silver steel strap on the back. Why?