Dedicated 20 amp circuit - Electrician laughed!

I have three dedicated lines in my sound room.  I’m running two Krell EV 600 monoblocks. Each has its own 20 amp circuit, with hospital grade outlets and 10 gauge wire. I’ve never tripped the breakers, but am more cautious with my hearing than I used to be. The rest of my room is on another dedicated 20 amp circuit.  All are wired to the same side buss. I however do not have a dedicated ground.  I’ve never experience any ground loops or hum and am very thankful. 

He’s Not really correct.  I’ve had huge improvements going to a dedicated circuit when OTHER ITEMS on that same circuit are noisy.  Fluorescent lights, hair dryers, microwaves and vacuum cleaners are quite noisy and will cause visual (TV-projector) mouse as well as audible noise.  A dedicated circuit can help in those cases.

A good wiring technique (USA) is to put the noisy items on one “leg” in the electrical panel and keep the audio items on the other “leg”.  (In the USA, boxes are fed with dual 120V wires or “legs”; most circuits only use one, unless they are a 220V circuit.  Air conditioners, stoves, air compressors, welders are 220V and all else is 110).  The wiring strategy is to keep bathroom circuits (hair dryers)  and living room / bedroom / hallway circuits (vacuum cleaners) and buzzy lighting circuits (fluorescent) on one leg and audio on the other.

His assumption in needing to run a new ground is based on issues with ground loops.  If the length of wiring on all audio circuits to the box is the same, ground loops are often avoided until you introduce coaxial cable into the mix.  Use isolators if that happens.  RCA cables (subwoofers) also cause ground loops; in that case consider higher-end gear with XLR interconnects or use isolators on the sub RCA’s.

Also, high end gear can have huge current draw, especially with Class A gear.  Sharing circuits can cause tripped breakers or blown fuses.  If your lights dim and flicker during loud passages, you need a dedicated circuit.

Some Laws are meant to be broken. I broke two this morning and it’s not even lunchtime yet. But some theories have passed from theory to Law. To whit, the Laws of Thermodynamics. We also have F = ma 

https://en.wikipedia.org/wiki/Laws_of_thermodynamics

We are in the early stages of building a home, one with a "bonus room" above the garage for my "man cave".

Since we had all sorts of options to customize, I decided to have the builder install a dedicated 20 amp circuit to where my component rack with live.  I'm not sure it'll make a difference, but what the heck, it can't make things sound worse.

I have an "all digital" source system, and I have found that the better control of the AC power, the better my DAC's perform.  I upgraded my power conditioner from a PS Audio P10 to a P15, when the P15 became available, and the result was and immediate and significant improvement in the clarity of the bass, improvement in the sound stage and the sound seemed a little more "relaxed"...both with my PS Audio DirectStream DAC and my Mytek Brooklyn DAC.

So, I wouldn't discount the wisdom of installing dedicated AC lines, though I can't "prove" they make a difference, my experience with power conditioning was pleasant and unexpected.