15 amps vs 20 amps

Firstly, let me state that I’m no electrician so forgive my ignorance about all this....

My wife and I have just moved to a new house.  We’re very happy, but there’s something unusual about the house! The great news is that it’s almost completely Ethernet wired and came with a kick-ass networking system. Fabulous wireless and Ethernet performance everywhere.

After a few days unboxing and settling in, I thought I’d rig up my system.  This is where the apologies start - I hadn’t actually noticed that most of the house is supplied by a 20 amp circuit, until I tried plugging in my Audioquest Storm power cable, which is meant to connect to my15amp Niagara power supply, and then to my components. No harm done, but the plug was clearly not fitting easily into the outlet. I didn’t force it and stopped  my installation. 
It looks like setting up my system is going to be a project.  Firstly, can anyone tell me if it’s ok using 15 amp audio components through 20 amp outlets? Do I need to change anything like fuses, plugs, outlets? Will 20 amps be good/bad/same for performance? Safety concerns?

As you can tell, I know very little about this and would prefer not to make a costly mistake.

thanks for any advice.

OP; buy a 20 amp outlet, such as the one in the link I posted above.
It's a very good outlet that has been cryogenically treated the correct way.
I believe that outlet will sound better than the identical outlet that was not cryogenically treated. The only exception to what I just said would be if you wanted to purchase a different audiophile-grade outlet that costs significantly more.
@lak Yes I think it makes sense to upgrade the outlet.  I did this in my old house and was surprised at how much SQ difference it made.  Taking your advice I put in another 20 amp outlet.

The house is not new but was fairly recently rewired.  I believe the previous owners operated some kind of small business in the house - which accounts for large number of outlets, 20 amp circuits and pro-grade network installation.
Most people will only give you an opinion on what to do. Everyone has an opinion. Few are technically correct, some may be compliant to code, but compliance isn’t the same thing as the safest and best-performing solution. Many are mis-informed and can lead you to an dangerous installation which could result in an electrical fire. 
The most dangerous thing to do is something that you don’t understand yourself. Get an electrical contractor with at least two good references that is licensed to do residential electrical work by the electrical safety authority in your area. They should be competent in their job, and capable of advising your with the safest and best performing options for what you want to do.
The house is not new but was fairly recently rewired.

If the rewire was done after 2009 there is a good chance the governing AHJ (Authority Having Jurisdiction) adopted the 2008 NEC section in the code requiring TR outlets in habitual areas in a dwelling unit.

Is the duplex receptacle a TR outlet?