Power to the System

[leonski]

Many audio people have spent much $$$ getting a system together.
But powering it is just as important as the selection of gear.

Choose 2 answer......for me, for example, I have one 'shared' circuit and one 'dedicated' circuit.   
Since I have a 2.1 system, this is quite adequate.

But for those of you with 5 amps and 2 subs?   or MORE?    

[adaboy]

Jan 5, 2019 20:57:01 GMT -5 leonski said:

Many audio people have spent much $$$ getting a system together.
But powering it is just as important as the selection of gear.

Choose 2 answer......for me, for example, I have one 'shared' circuit and one 'dedicated' circuit.   
Since I have a 2.1 system, this is quite adequate.

But for those of you with 5 amps and 2 subs?   or MORE?    

As an electrician, I totally wouldn't mind putting dedicated circuits for my theater; however, since my room and panel are on complete opposite ends + 2 story I'm in no hurry to do it. So for I've had zero issues with power.

[emofrmcgy]

I have my projector on it’s own 15amp circuit. And 2 dedicated 20amp circuits for my A/V rack.
So I chose 3 dedicated.

[novisnick]

Jan 5, 2019 21:06:52 GMT -5 adaboy said:

Jan 5, 2019 20:57:01 GMT -5 leonski said:

Many audio people have spent much $$$ getting a system together.
But powering it is just as important as the selection of gear.

Choose 2 answer......for me, for example, I have one 'shared' circuit and one 'dedicated' circuit.   
Since I have a 2.1 system, this is quite adequate.

But for those of you with 5 amps and 2 subs?   or MORE?    

As an electrician, I totally wouldn't mind putting dedicated circuits for my theater; however, since my room and panel are on complete opposite ends + 2 story I'm in no hurry to do it. So for I've had zero issues with power.

I’m not an electrician but I’m in a similar boat, panel and HT room on the opposite sides/floors of the house. 😢 sure wish it wouldn’t cost an arm and a leg to install a couple of 20 amp services.

[Bonzo]

I have (1) 20 amp dedicated line, that goes to one box in the ceiling, and then splits to (2) dual outlets. So basically everything runs off (1) 20 amp line.

I run (2) PF-60 Belkin units, (1) off each line, then all plugs into those units.

Belkin 1
XPA-2, XPA-5, 3 front speakers, TV

Belkin 2
Everything else.

Never had an issue. But could be better I guess with 2 lines to each Belkin. Will NOT run without them. Harsh.

[adaboy]

It does need to be stated that the max wattage from a 15a circuit at 120v is 1800, and 2400 watts for a 20a circuit. If your devices try to draw more amps than the breaker it will cause the breaker to trip. Outside of potential noise issues dedicated circuits really are only needed if you are using the power or plan on using the additional power in the future. It's like why most home main panels are rated for 100a up to 200a. We don't use as much at one time as we think we do. As an example add up all of the numbers on your breakers in your main panel plus any sub panels. Guaranteed you will exceed the total number of your main breaker 100a or 200a. Most people don't need dedicated circuits unless of course.. They do.🙂

[leonski]

120v and 15 amps is Indeed, 1800 watts. That however, is a SHORT TERM rating. The real, continuous or 'long term' value is a -20% 'derate'.
That's 1440 watts on a 15 amp circuit and 1920 on a 20 amp circuit.
In addition? And I'm less clear about this, I'm certain that Voltage Sag play a part in further reductions in power. Also, the fact that FEW loads are actually pure resistive is ANOTHER 'derate'. This is called Power Factor and is basically the effect
of a load appearing as a capacitor or inductor to the power supply....

Back to Voltage Sag? I RARELY have 120v at my house. In the Hottest part of the summer, during the hottest part of the day? I'll frequently see <115v on my line. Based on experience, at that point I'm thinking Brown Out. This IS after all, California,
where new generating capacity is tough to come by and all it takes to bring down the house is somebody tripping on the ExtenSion Cord from Arizona. It's happened and resulted in 12 hours of blackout at MY house, shorter and longer elsewhere.

We (the nation) are making things worse with all-electric automobiles. These frequently charge at night, during the low-demand time when MAINTENANCE is typically done on power plants. Rates are also lowest then, in areas where this has become the norm.
I cringe when I think how much it will cost to FIX all the electric cars plugged in when a lightning induced surge takes out part of the grid. I'd be REAL careful were I to live in a lightning-prone state.....Maybe anywhere in the South East / Tornado Belt or FLORIDA.

For ADABOY? My panel is pretty stuffed. My changes and addition of my 20 amp circuit was accomplished with 1/2 width breakers. If I were doing a clean-sheet install? I'd have a sub panel of 4x20 amp breakers. And maybe some expansion room? Feed the panel with CONDUIT, not ROMEX
so it could be grounded / RFI insulated and run 6ga or 4ga to the panel. Whatever's right. Again, a derate for temperature and 'bundling' of multiple conductors.

[adaboy]

Yep you are correct about variations of voltage and heat/demand factors, I didn't want to get into the nitty-gritty of the details for the average joe. When adding a subpanel thats the way to roll. Nothing wrong with what you have, and you can still add a subpanel even if some of your current breakers need to reside in the new panel.

[chicagorspec]

I have three 20 amp circuits. Each channel’s amps are on one circuit (2-Channel only, no HT), with everything plugged straight into the wall. Front end components are powered from the third circuit via CMX-6, with a LPS powering the 12VDC Wavelet and 19VDC SGC sonicTransporter.

[audiophill]

I have more than 3. I have 4 XPR amps each on it's own 20 amp circuit and the rest of the system on a 15, so 5 circuits in all for my system.

[Gary Cook]

Sorry I don’t understand the question, actually the range of options. My house has 8 x 220/240 volt circuits, the hot water service is on one (that’s off peak), cooking (stove, cook top, etc) is another, there is a 20 amp circuit (for the welder and the air conditioning) and the other 5 circuits service the rest of the house. My gear is split between 2 of those circuits with each one rated at 3.6 kw ie; 240 x 15 amps.

Cheers
Gary

[millst]

A common misconception is to treat circuit breakers like hard cutoffs. Breakers supply more than 15/20 amps all the time. They are designed to prevent a constant draw that would destroy the wiring. Devices like vacuum cleaners create a large inrush current when turned on, way more than the breaker rating. The breaker has a reaction time. That time could be in seconds for a minor over-current situation, but fractions for a large one.

Music and movies don't demand constant power. The signal level is varying up and down all the time. Plus, we rarely ask our amps to go anywhere near their max draws. I have over 6000 watts in amp power and have never tripped the breaker, even with the volume at 0db.

Next go around, I'd like to plan for dedicated circuits. I'm sure there is some detrimental effect to sound quality when the circuit struggles to provide power. Of course, it's probably down in the noise and only worth worrying about after you've hit the big things like room treatment.

-tm

[leonski]

I'd ask mllst a couple questions, if I may?
1. What is speaker sensitivity?
2. What is voltage drop at the outlet when REALLY pushing it?

Agreed. Circuit breakers are NOT a 'brick wall'. But at the same time, while spiking current draws, the voltage is also spiking....in the down direction.

So far, it appears that about 1/2 of all voters have ONLY a single shared circuit........

[pknaz]

Jan 6, 2019 17:24:24 GMT -5 leonski said:

I'd ask mllst a couple questions, if I may?
1. What is speaker sensitivity?
2. What is voltage drop at the outlet when REALLY pushing it?

Agreed. Circuit breakers are NOT a 'brick wall'. But at the same time, while spiking current draws, the voltage is also spiking....in the down direction.

So far, it appears that about 1/2 of all voters have ONLY a single shared circuit........

I had similar amounts of power on tap, and cranking above 115db(c weighted) at the listening level (about 120db 1m away from mains), at roughly 89db/1w/1m, on a single 15amp circuit, I never ran into issues. 4,000 watts on the subs (4 of them), and 1,000 watts on L/R speakers. Don’t know what the sensitivity of the subs were, but I pushed them pretty hard at those levels, and the XPA-1’s were pushing their meters far into the right side of the display.

[leonski]

When I ran a SINGLE amplifier of 2x200 into my early Magnepans, I would flicker the lights to the house on the 'common' 15amp circuit shared.
Amp at this point was near redline and speakers near their power limit.

My current speakers of roughly 6db worse sensitivity than pknaz, would require 4x the power for similar levels.

Keep in mind that 4kw on the sub is really a FRACTION of that as continuous. 'D' amps are poor at continuous power due to heatsink issues. ASP modules from B&O are either 30 seconds or 60 seconds at full tilt.

While it's fine it ran and you liked it, I'd really like to know the Voltage Sag, which is potentially the limit. Technical types who bench test for a living will use a VARIAC to stabilize line voltage to get a proper reading.

And excuse my doubt, BUT, the quote of say.....120db implies either 100db continuous, which is pretty darn loud OR 140db peaks, which is beyond most speakers limits. In either case the 'crest factor' is 20db.
It is possible these days with well recorded music to exceed 20db, which is still a pretty darn good swing.     

Please reinstall your ear plugs, and repeat with before and during voltage measurements. Best with a scope, but if you have a peak hold meter, that might work, too. I'd plug a 60 watt bulb into an outlet on the same
circuit and measure across THAT.

I may make a trip to the home store and make a way to measure......without risk of short or messing with the load.   

[highfihoney2]

Jan 6, 2019 1:15:31 GMT -5 leonski said:

120v and 15 amps is Indeed, 1800 watts. That however, is a SHORT TERM rating. The real, continuous or 'long term' value is a -20% 'derate'.
That's 1440 watts on a 15 amp circuit and 1920 on a 20 amp circuit.
In addition? And I'm less clear about this, I'm certain that Voltage Sag play a part in further reductions in power. Also, the fact that FEW loads are actually pure resistive is ANOTHER 'derate'. This is called Power Factor and is basically the effect
of a load appearing as a capacitor or inductor to the power supply....

Back to Voltage Sag? I RARELY have 120v at my house. In the Hottest part of the summer, during the hottest part of the day? I'll frequently see <115v on my line. Based on experience, at that point I'm thinking Brown Out. This IS after all, California,
where new generating capacity is tough to come by and all it takes to bring down the house is somebody tripping on the ExtenSion Cord from Arizona. It's happened and resulted in 12 hours of blackout at MY house, shorter and longer elsewhere.

We (the nation) are making things worse with all-electric automobiles. These frequently charge at night, during the low-demand time when MAINTENANCE is typically done on power plants. Rates are also lowest then, in areas where this has become the norm.
I cringe when I think how much it will cost to FIX all the electric cars plugged in when a lightning induced surge takes out part of the grid. I'd be REAL careful were I to live in a lightning-prone state.....Maybe anywhere in the South East / Tornado Belt or FLORIDA.

For ADABOY? My panel is pretty stuffed. My changes and addition of my 20 amp circuit was accomplished with 1/2 width breakers. If I were doing a clean-sheet install? I'd have a sub panel of 4x20 amp breakers. And maybe some expansion room? Feed the panel with CONDUIT, not ROMEX
so it could be grounded / RFI insulated and run 6ga or 4ga to the panel. Whatever's right. Again, a derate for temperature and 'bundling' of multiple conductors.

.
If I we're building from scratch I'd have every high wattage draw line installed in 240 volt for all my amps ,a 240 volt load generally draws half the amps of a 110 volt load ,my grow rooms are wired for 240 volt from a 100 amp sub panel ,the 240 allows me twice the voltage from the same 100 amp service .

[leonski]

It'd cost a Fortune to upgrade my existing. I'd want at least a 200 amp service to provide for a future All-Electric auto as well as a sub-box for stereo / HT

For a new, clean-sheet build? Still cost a bit but you wouldn't have to go thru the tear-down than rebuild situation with all the inconvenience THAT would bring.
Easier to do something right the first time than keep fiddling with it.....

[mgbpuff]

Leonski said "120v and 15 amps is Indeed, 1800 watts. That however, is a SHORT TERM rating. The real, continuous or 'long term' value is a -20% 'derate'.
That's 1440 watts on a 15 amp circuit and 1920 on a 20 amp circuit." You are misinterpreting a NEC rule for general purpose outlet circuits that was designed to allow for diversity of plug in device loads. If you know the exact load, you must design for that exact load, but if you do not know the exact load (general purpose outlets) then you must use load diversity rules (300 or 400 watts per outlet and only 80% loading of a circuit using such approximations). In actual use, however, a 20 amp circuit breaker will protect 20A rated wire continuously at 20 amps. A 20 amp cb will also allow for transients up to at least X6 for transformer initiation. Also, the brief transient surges in audio amplifiers are buffered from the line by energy stored in the massive capacitors in most linear power supply type amps (another reason why we like transformer type power supplies).

[thrillcat]

I only have a dedicated circuit for my theater because the previous owner was using the room as a workshop and he had it installed for his various power tools.

[millst]

Jan 6, 2019 17:24:24 GMT -5 leonski said:

I'd ask mllst a couple questions, if I may?
1. What is speaker sensitivity?
2. What is voltage drop at the outlet when REALLY pushing it?

Agreed. Circuit breakers are NOT a 'brick wall'. But at the same time, while spiking current draws, the voltage is also spiking....in the down direction.

So far, it appears that about 1/2 of all voters have ONLY a single shared circuit........

92 for the M&Ks in the theater and 88 for the KEFs in the secondary setup. Yeah, I wouldn't mind dedicated circuits for that and isolation from noise, but it's an older house and the panel is on the opposite side of the house. Not going to be cheap.

-tm