Main vs. sub panel for dedicated lines

Lowrider57, I will use 10 ga and 20 amp breakers for each line. Or I will use 12 ga and 15 amp breaker for the digital one. I will use high grade 20amp receptacles for each line.

Jea48 hit on the reason for the sub panel. I need more circuits. And also the fact that I may not need the sub connected to ground rod. I think I have been told that this depends on the distance between panels, if too close there can be problems. The distance between the two panels will be less than 15'. I will ask my electrician regarding need for this and do as he says.

gs5556, No circuit will require a length of Romex longer than 50' so voltage drop should not be a concern.

Mijostyn, yes I thought that it would likely make no difference, however since I need(want) a sub panel  I thought I could isolate high current circuits from those supplying outlets, lights, and the audio system in the addition. 

Thanks all!

And also the fact that I may not need the sub connected to ground rod.

Like I said I would not recommend it. It will not improve the sound of your audio system. In fact it may degrade the sound. Lightning loves an auxiliary grounding electrode though. Lightning strike travels through the earth, enters the aux ground rod travels up through the ground wire to the equipment ground bar on its way to the main electrical and on its’ merry way back to earth. Suppose it stops and looks around inside the sub panel on its’ way back to earth?

The earth does not possess some magical mystical power that sucks nasties from audio equipment.

Adding an additional ground rod to the main electrical service Grounding Electrode System may lower the grounding electrode to soil resistance. IEEE recommends 5 ohms or less.

FYI the main reason for connecting the electrical service to the earth is for lightning protection. You can have as many ground rods installed for the main electrical service as you like as long as they are all tied, connected together, and connect to one point at the electrical service equipment. No matter how many electrodes there are they are counted as one.

The distance between the two panels will be less than 15’.

How big/size, ampere handle rating, will the two pole breaker in the main electrical panel be that will feed the sub panel? Feeder wire size?

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@jea48 @mesch
I have a new service panel and a subpanel. When the sub was installed, a second ground rod was added. Two different electricians installed the panels, both said two ground rods were required to meet PA code.

Edit... the 2 panels are near each other on a basement wall.

@jea48  @lowrider57  I will consult with my electrician on the amperage supply to the sub panel and the need for sub panel ground rod.

Regarding audio quality would I benefit from running my system through a sub panel that only serves low amperage devices, my amplifier likely the highest one, over running it off the main panel to which the sub panel is attached?   

SQ has been debated, but keep the audio system together on the same leg (phase).