[myview]

Dear all,

I will soon be renovating my new house.  I plan to have the electrician run a separate line of 20A into my small dedicated music listening room.

The equipment will be:
- Model T Active speakers
- 1 unit of BAX-1 digital crossover
- 1 pair of 28B cubed
- 2 pairs of 7B cubed
- 1 unit of BP-17 cubed
- 1 unit of BDP-1
- 1 unit of BDA-3
- 1 unit of BCD-1
- 1 unit of BSG Technologies qol Signal Completion Stage
- 1 unit of Torus Power CS-16 Int'l UK S

I am totally non-technical so I am seeking advice here.  Is the 20A circuit sufficient for my needs (assuming all the equipment listed above are powered at the same time)?

Thank you

 

[JLM]

Yes, one 20A circuit should be sufficient, but why not ask Bryston?

Yet, when I built in 2005 I had the electrician run 3 dedicated 20A circuits just for my audio gear (the panel is in the next room over).  Each ran to a single cryogenically treated 20A hospital grade duplex wall receptacle.  And all 3 are grounded together on a separate ground from the rest of the house as recommended by an audiophile/electrician.  Note we have underground electrical service with our own transformer and all new appliances. 

This was strictly done on a 'while I was at it basis' as I've never had an issue with power aberrations at home (but have heard it elsewhere) and my systems have always been relatively small/modest.  The electrician worked on a fixed price, the receptacles cost $100, the gear is in a private 8ft x 13ft x 21ft (Cardas Golden Cuboid) basement listening room/office that is quite effectively physically isolated (at first was rather spooky) yet overall the space didn't cost more per square foot than the rest of the house and doesn't look weird (beyond having an exterior door inside the house).  So a very practical solution (insulated staggered stud walls, flexible/insulated ductwork).  Unfortunately the builder balked at installing a drywall ceiling using gauge metal Z-channel furring strips, but the room is well removed from living/sleeping spaces.

Room size/shape/setup/isolation are far more important considerations than power aberrations IMO.  Hope you've got those issues covered.

[paulg]

One 20A will do nicely.We had the same opportunity when remodeling, and laid in one 12 AWG run from an on-line 3 kva UPS. I am powering five pairs of amplifiers, including two 18" 400 watt subs. When cranking full throttle, power usage on the UPS is 30% and AC current dwells around 7 amps. No sign of strangulation. A single dedicated 20 amp circuit wired per code will definitely NOT run out of steam.

[Speedskater]

With 120V Ac, a 20 amp circuit is plenty, but big home theater systems are another story. Have the electrician over-size the cable by one step (like 10AWG). Run the cable to a centrally located junction box, then star out to the outlet boxes.  The idea is to keep the total length of power cords from one hi-fi component to all other components short. Use real SouthWire brand Romex®.

For big home theater systems, run a 120V feeder to a centrally located small breaker panel, then repeat as above.

[TJ-Sully]

Hey MyView, that's a helluva system you got going there man. Nice work! I bet it sounds terrific.

I am also considering running a single 20a dedicated line to my listening room - a non active all Bryston setup.
Check out what Paul McGowan has to say about wiring a room. Some good intel.
https://www.psaudio.com/askpaul/house-wiring-for-high-end-audio/

You'll have to let us know how things shape up - and sound!

Cheers, TJ

[Big Red Machine]

Some guys put 3 20A lines. To separate the sources from the amps, etc. I wish I added a 30A line for some of the badass amps I have looked at!!

[Tympani]

As long as you are remodeling, why not "over-build"? Those beefy amps should have their own 20A line. Another for the Speakers/x-over. And a third for the digital components. You will have to decide where the Torus is best applied (I would suggest running the amps straight out the wall)

So, minimum 3 lines, maybe a 4th for added security, or if you want to have the 28's and 7's on their own lines.

Agree, pay attention to good grounding principles, good outlets, and quality Romex.

[Elizabeth]

Also, if you get more than one line. They must be all on the same 'leg' of the 240v coming into the house!
If you allow the electrician to use one from one leg, and one from the other, you could have a 240 volt (more lethal) ground fault running across some connector.
Which might harm you, but would also destroy the equipment connecting the two.

Sadly most electricians would not think twice about using both legs..
And they need to be clear they cannot do so.

[woodsyi]

Consider putting in this subpanel.  I got one for 2 lines.

https://zerosurge.com/wp-content/uploads/2016/11/FF1-Series-0318.pdf

[Speedskater]

Consider putting in this subpanel.  I got one for 2 lines.
https://zerosurge.com/wp-content/uploads/2016/11/FF1-Series-0318.pdf

That's not a sub-panel.  That's a very nice and very expensive surge protector.

[Speedskater]

While most hi-fi systems don't need more than one 20A circuit, but large home theater or huge power amps might.
So if more than one circuit is needed. Run a heavy 120V from the main breaker panel to a central point in the music room.  There place a small breaker box to split in to the needed 20A circuits.

[myview]

Thank you all for your responses.

[Wim J]

I'm on 240V powernet . I have a seperate 25A fuse for the audio setup. From the fuse I run a 3AWG cable to a torodial separation transformer capable of 5kVA continuously . This transformer powers my complete system with balanced power. It is located next to the audioset to keep cables to the individual components as short as possible. The system also has its own grounding, which has nothing in common with the grounding of the rest of the house. I even have a seperate grounding rod for this circuit.
Does all this make the full Bryston set sound better than the inwall 13AWG cable?     

[R. Daneel]

An electrical engineer can give you the best advice. Don't listen to electricians.

20 Ampere line will be sufficient to power any system. Keep in mind you will never use all the amplifiers at full power. If you had two 28B amplifiers which can likely draw 2 kW each, running them at full power would trip the main house circuit breaker. But as it is, this power is used only during short transients. In reality, a 2 kW electrical heater will draw more current than most audio systems.

To put things in perspective, our PA system we use for live sound in big halls draws about 1,5 kW constant power. This is with multiple 18'' bass drivers and a 19'' rack of 4 stereo power amplifiers rated at 3200 W each, not including the digital effects processors, preamps and the mixing desk.

Here's a short guideline in a sort of a "hand-waving" way:

P = U x I x cos"PHI" where
- P = power (Watt, W)
- U = voltage (Volt, V)
- I = current (Ampere, A)
- cos"PHI" = non-dimensional coefficient corresponding to the difference between taken and delivered power ; assume this coefficient to be 0,90 with most modern appliances

Grounding is a greater concern than raw current draw when it comes to audio/video applications. Don't waste your time and energy on things that don't matter. Proper acoustic treatment will bring far more benefits than other things considering the cost.

Cheers!
Antun

[Marius]

sorry to bump this old thread, but I am experiencing issues related to this topic I fear...


my system is powered on a dedicated 20A line, with a breaker using a slow characteristic (C20) supposedly to mitigate power rush in at startup. Has always worked fine. The trouble started (I think) when I decided the power draw from the 28bs in standby mode (both 6 watts) should be cut, and power the system via a remotely controlled socket switch. Thus ensuring no power is used at all when not playing.


can't really pinpoint the number, but ever since, the ground braker tripps when powering the system. Mind you the 28b's are in their Off state at that moment, I always carefully assure they are, so this isn't a matter of huge power rush inns to the amps (I should think).. I can hear a deep 'clunk' when this happens, and this is clearly something else than the wonderful sound the 28b's make when actually turned-on.


@james, could you please have a look for me, and check what the 28b's do when powered (as in: have their power cables stuck into the wall sockets). What specs can you give me?


I'll have my electrician come over next week to check the house installation, so would appreciate any pointers you could give me for that inspection too.


___Update___

after some serious 'pulling of the power cord' while the 28b was completely naked, ie no connection to a speaker and 10bsub, things seem to go alright, though I can still hear the occasional 'clunk' inside the 28b. No tripping of the ground-breaker switch just yet.
But, connecting the balanced (XLR) from the 10Bsub out to the 28b, and connecting the power cable to the wall socket (directly, no remote switcher) the ground breaker tripps.


I am in contact with the dear people at Mafico, but would appreciate your thoughts as well of course.