[brj]

For those that have installed a sub-panel with dedicated circuits to feed your audio system, did you run 240v from the mains panel to the sub-panel, dropping it to 120V (20A circuits) at the sub-panel, or did you connect the sub-panel to the mains with a single phase 120V connection?

I would imagine that running 240V to the sub-panel would give you better common mode noise rejection on that run, but the consequence is the need to pull from both phases in your mains panel.  This would presumably negate the value of moving all circuits feeding motors (HVAC, refrigerator, washer/dryer, etc.) on the opposite phase of your audio circuits.

I wasn't seeing much benefit to the 240V connection in this case, but I didn't know if I was missing something fundamental...

Thanks for any comments!

[Speedskater]

I think that strong arguments can be made for or against either way.
For a system that has lots of real big power amps, I would definitely go with a 240 Volt system with the amps evenly divided between both phases.

[rofo]

For those that have installed a sub-panel with dedicated circuits to feed your audio system, did you run 240v from the mains panel to the sub-panel, dropping it to 120V (20A circuits) at the sub-panel, or did you connect the sub-panel to the mains with a single phase 120V connection?

I would imagine that running 240V to the sub-panel would give you better common mode noise rejection on that run, but the consequence is the need to pull from both phases in your mains panel.  This would presumably negate the value of moving all circuits feeding motors (HVAC, refrigerator, washer/dryer, etc.) on the opposite phase of your audio circuits.

Based on you description above hire an electrician to do your work before you hurt yourself you do not know enough about this. There is no such thing as 2 phase power as you refer to "both phases". PS. keep all your AC for your system on the same side of the panel.

[Occam]

Rofo,

I don't see brj referring to anything as 2 phase while referring to the N.A. 240vac split phase, nor do I see it as inappropriate to refer to both legs as 'both phases'[they are 180 degrees out of phase relative to each other], although he should refer to it as 'both legs'.
Point of fact - the last 2 phase power transmission lines (90 degrees out of phase with each other) were retired from service in the Buffalo, NY region about 15 years ago.

brj,

That'll teach ya, ya young whippersnapper! 
The rational for for using both phases legs, splitting the power to monoblocks is that typically low bass is mixed evenly on both channels and powering one side with power 180 degrees out of phase with the other will partially balance the load, minimizing induced harmonics. I've no personal experience with this technique.

FWIW,
Paul

[brj]

Thanks for the responses.

For what it's worth, it was one of the electricians giving me a quote that brought up the option.

Actually, "2 phase power" has been used in the past, but it was not my intent to imply the use of 2 phase power.  To be precise, we use "split phase" residential power distribution in the US - single phase, 3 wire, with the 2 hot legs 180 deg out of phase (or 180 deg offset relative to neutral, if you prefer).

With that said, the question still stands - has anyone found a compelling reason to run 240V to your dedicated audio sub-panel instead of 120V, given that all circuits from the sub-panel will only be 120V?

Thanks!

[brj]

Just caught your post, Paul - thanks!

You've distilled the point better than I - a chance at a more balanced load with reduced harmonics vs. avoiding the influence of household motors on your audio.

(I'm not worried about the manually controlled motors.  If I'm running my garbage disposal, I'm not listening to my audio system!  The HVAC related motors and refrigerator, however, usually run on their own schedule.)

[Soundminded]

For those that have installed a sub-panel with dedicated circuits to feed your audio system, did you run 240v from the mains panel to the sub-panel, dropping it to 120V (20A circuits) at the sub-panel, or did you connect the sub-panel to the mains with a single phase 120V connection?

I would imagine that running 240V to the sub-panel would give you better common mode noise rejection on that run, but the consequence is the need to pull from both phases in your mains panel.  This would presumably negate the value of moving all circuits feeding motors (HVAC, refrigerator, washer/dryer, etc.) on the opposite phase of your audio circuits.

I wasn't seeing much benefit to the 240V connection in this case, but I didn't know if I was missing something fundamental...

Thanks for any comments!

The panel should be wired for 120/240 to meet the requirements of the National Electrical Code. This is because the panel must be installed as the manufacturer recommends. You should also get an electrical permit for the work and have it inspected by the local code official in your town if you are permitted to do it yourself. If you don't and there is an accident you may not be covered by your homeowner's insurance.

Transformers for residential buildings are classified as single phase center tapped. The center tap is grounded at the entrance to your house and serves as the neutral return. The neutral and ground can only be connected to each other at one point, where it enters your house usually inside the circuit breaker panel.