Dedicated 20 amp circuit - Electrician laughed!

I’ve done isolated/home-run dedicated circuits for high power pro installs.

Makes all the sense in the world, when the peak draw might and does easily hit/peak at 2500-4000 watts per run line. (eg, double 18" JBL bins per bridged amp, etc). Keeps noise down, and keeps the transients clean.

A house system that really cooks... and is set up so the bands passing though get the best acoustics and the best electrics they’ve ever dealt with.

Gotta keep the beer fridges, lighting, etc, on separate lines.... and a on a separate panel, if at all possible.

And always advised show runners to have an electrician come in and check the connectivity quality of all the lines to be used in all the rooms that are slated to have gear demo’d in them. Reset all breakers, re-set all screw connections for the given power for each line, grounds re-seated as well. Some of those lines/grounds have not been serviced in a decade or more. (depending on the given hotel)

This make a huge difference, overall, for the given audio show. People notice noise, but they don’t notice the absence of noise, so it’s difficult to quantify, for the average Joe. Except to note that the given audio show seems to have gone well.

and bring incandescent bulbs to the show and replace the led and ccfl bulbs in the given room you demo in.

the resistive filaments in the incandescent bulbs will lower/dissipate peak HF line noise and help stabilize the specific line in use. a great secret weapon, that most won’t even ’get’. Eyeballs/brains/minds are also a lot happier (unconsciously so) with incandescent bulbs in play.

This is quality audio created by the cumulative inch, where it adds up to feet of quality increase, when you do it right.

this is the beauty of our hobby... does it make a difference, can I hear it, can you hear it? if you want to hear it, you will. if it makes you happy, do it.

In my new home I first tried a sub panel with a whole house surge protector, dedicated 20 amp circuit, 12 gauge wire and Furutech receptacles, which definitely helped but got me nowhere near the black backgrounds, voltage stability and dynamics I had in a private recording studio I built years ago. 
So I did what I did in that long-gone studio and ran a dedicated 240v circuit with 6 gauge wire feeding an Equitech balanced power system sized for my system.  5kw in this case vs. the 7.5kw I had in the studio. I’m a very happy camper once again. 
If you choose to go down this path, do your own research on whether you can meet code for a “technical” balanced power installation. There is a white paper on the Equitech website. You might also talk to the guys at Vintage King about balanced power. They supply many studios with both new and classic gear. 
Just my 2 cents...

My dad is a mathmatician and an electrician and a jack if all trades. He taught me to work on cars.

When I was in college I told him that I put 120lbs of air in my bicycle tires. He laughed at me. He said a car tire doesn't take more than 35lbs.

I knew what I had just done had worked...so I said it was pressure, not volume.

I think most electricians see the rating on a gauge of wire and think capacity...but not resistance.

I just put a dedicated line. Luckily I had an open minded electrician. It made a small but noticable difference in every area: bass, focus, clarity.

Your electrician is dead right except for one thing, an extremely powerful class Amp which will trip a 15 amp breaker.