Do your lights dim when your amp powers up?

I don't see how tightening screws would do anything to reduce such in-rush current so I would not bother doing that.  

That's exactly right, while it may be good to make sure your screws are all tight, in this case you would be INCREASING current delivery.  I've seen this happen before ages ago.  

The lack of resistance in the 10 gauge wiring is INCREASING the inrush current and dropping the voltage at the panel until that current is reduced.   A loose outlet screw (unsafe!) or 12 gauge/14 gauge wiring would all increase the R slightly and REDUCE the inrush current. 

Some amplifiers (Luxman for instance) include a slow turn-on circuit, which limits the inrush current during startup, then gets out of the way, but they are uncommon. This circuit introduces significant resistance in the AC until the large power supply filters are charged up and then shorts out of the circuit when the idle current has stabilized. 

My fridge motor going on makes the lights dim for a second, but not my hi-fi.... 

Thanks for the information, helpful to me in understanding what’s going on.  The lights in my listening room are a set of six ceiling cans with fairly high wattage bulbs on a separate circuit from the sound system, and supplied by 14 gauge wiring on a 15amp breaker.  Based on the discussion here so far, I am thinking the 20amp/10 gauge “pipe” supplying the amp is the path of least resistance, and robbing current from the lights when the caps charge coming off of standby, resulting in a very brief dimming. Not sure if the difference in gauge of the wiring makes that big of a difference in the amount of observed dimming, but I guess it’s possible. An easy test is to plug the amp into a different circuit that has a higher gauge supply wire and smaller amp breaker and see if the lights dim as badly. That would require a very long extension cord.

I will say that I have tried different amps and other components in other rooms in my home without dedicated lines, and even with headphones that remove room variables, everything sounds better on the dedicated line and the difference is not that subtle.  I can put up with lights going down briefly on start up if it means the amp is winning the war for current!  The amp I looking to buy is more powerful than this, so I guess I will just have to get used to it.

kn

Hi , I had similar problems in my 40 year old house. 2 years ago I added Solar and during the process I had a brand new panel installed. Prior to that I had an issue where my pool motor ( single speed at the time ) was not running smoothly. The issue was a WEAK breaker that wouldn’t hold the current. While replacing it , I noticed the bus bar was pitted and moved it to a new location, problem solved. I also TIGHTENED all the connections. Now with a new box and a variable speed motor no issues. I just had the kitchen remodeled a few months ago and we did all new kitchen wiring for all new appliances. We went to a large induction stove that requires a 50 amp circuit. We went 6 gauge and it’s rated for 60 amps but has a 50 amp breaker. When we kick it on high , turn on the vacuum or use the tea pot I get a very slight startup flicker in other lights. Like mentioned above if is just a fraction of a second don’t worry. As mentioned above i strongly urge you to check for loose screws/nuts at the panel and check for tired breakers as they are cheap to replace. Regards, Mike B. 

I would add that the experiment of using a long extension cord can cause voltage drop, which in turn may increase current draw.