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

a few lights, modem, router, weather station and a couple network switches all living off of a 15 amp circuit with lots of room to spare I believe. Sounds good.  Then I added 2 dedicated circuits with 10 gauge wire for all the audio gear and it has been noticeable in a very favorable way.

. . . and it might not be the multiple circuits and the 10 gauge wire that made the improvement . . . it might be all the crap that you got off of the audio circuit(s). 

A dedicated circuit is a dedicated circuit until you muck it up by adding a space heater to the same quad box your preamp is on. Don’t ask me how I know this.

But @curiousjim , I must ask:  how DO you know this??

@jumia  , now I am the one who is confused.  This, below, indicates that you have two multibranch circuits, not two dedicated circuits?

and while 2 dedicated circuits would be highly preferable I’m not sure existing multi branch configuration I have is achieving anywhere near what 2 dedicated circuits would achieve.

Then I added 2 dedicated circuits with 10 gauge wire for all the audio gear and it has been noticeable in a very favorable way.

Yes, you can do it. Wiring one quadplex outlet on one branch circuit is the same as two duplexes on one branch circuit. The quad give you the convenience of plugging everything at one location and, more importantly, at one ground point.

A dedicated circuit means the circuit is dedicated to the audio gear -- not the receptacle. Multiple receptacles on one dedicated circuit has the disadvantage of having multiple ground points, increasing the chance of ground loop hum. This is why it's not a good idea to have one receptacle for each piece of audio gear. 

A point to keep in mind is that standard receptacles are rated for 15-amps. This is why continuous loads such as space heaters and hair dryers are rated at 1500 watts, or 12.5 amps, because it's 80% of the receptacle's 15-amp rating. Non-continuous loads such as audio amplifiers go over 1500 watts but it's okay to use a 15-amp receptacle because the time at the higher amperage peaks doesn't heat up the receptacle parts. A true 20-amp circuit has a 20-amp receptacle, which has a different blade configuration so a standard (15-amp) plug won't fit into it. You can recognize this receptacle as having a cross on the neutral blade -- to fit the up/down 15-amp plug neutral and the horizontal 20-amp plug neutral. So don't obsess over the "20-amp" circuit rating, because it's not 20-amps since the 15-amp receptacle is the weakest link.

Plugging everything into one quad is fine. Removing the tab on the quad to install two circuits is a waste of money, unless you have a high power amp. Plugging a high power amp into it's own circuit ensures optimal performance into low impedance speaker loads and has no other advantage than that.

gs5556

A true 20-amp circuit has a 20-amp receptacle, which has a different blade configuration so a standard (15-amp) plug won't fit into it.

Are we talking about the US? A 15A plug will fit into a 20A receptacle. The opposite is not the case.

Plugging a high power amp into it's own circuit ensures optimal performance into low impedance speaker loads and has no other advantage than that.

There are many potential advantages to dedicated lines, regardless of speaker loads.