Quad panel outlet - can I do one circuit on this?

Yes, a single 20 amp circuit can feed multiple 15A outlets.

I wouldn't do fancier than that unless you want to step up to using a single 20A/220V circuit and a step down isolation transformer in the room. :)

Until quite recently I was using three 20A circuits to fed three duplex outlets with four pieces of gear on them. I did the experiment of putting all four pieces of gear on one 20A circuit & tripped the other breakers to ,off (when I listen there is nothing else operating on that leg of the breaker panel) and although it is not a kick-in-the-balls change, I do believe I prefer the single 20A system.

Prior to performing the above experiment I was not predisposed to believing I would like one more than the other. As a matter of fact I was hoping that I would like the three 20A system better.

Of course, you didn’t ask about three circuits vs one circuit, you did ask about two vs one, and I did not try my system on two.

Immatthewj

I'm a little confused on this point. You had all your gear on one dedicated line versus having it spread around to 3 dedicated lines.

I understand not much of a difference which may speak to nature of the gear and your system and overall electricity quality.

But I think most might prefer the three dedicated line approach if you can do it. 

@jumia  , I was inclined to think along those same lines.  I read the thread that I am going to paste below and that is what got me interested in experimenting with one versus three circuits.  In all fairness to the multiple circuit school of thought, JEA has previously provided advice on how the circuits should be routed and segregated from each other in the attic, wall, and panel, and in all honesty, I did not meet his criteria when I was stringing the Romex.  But here is the thread I was talking about, and then I'll find the thread that JEA explains how he advises running multiple circuits.

@jumia below is another thread in which I believe JEA talks about how he suggests running Romex. And deviating from his advice may have an effect on the sonic result of multiple circuits. You did mention how gear might have an effect on what I heard when doing 3 vs 1 experiments, and maybe it would, I don’t know. I am running a Cary SLP-05 in front of a Cary V12, in front of a pair of B&W 805s supplemented with an old M&K powered sub, interconnects by Kimber Silver Streak and biwired (I think, but it was a long time ago) Kimber 6TC and 8TC.