Electrical Outlets and Amps

A

AndrewLyles

Audioholic
Howdy All,
So I'm looking to add some amplicfation to my HT set up and am curious how to figure out if my outlets can handle the load that I am going to be placing on them. Potentially 3 x 2-Channel amplifiers (400w @ 4ohm), receiver being used as a Pre-Pro, TV, DVD,CD, perhaps a power conditioner or two, video game console, you know, everything that one would hook up to their own system in the living room. Any input is always appreciated.
~Andrew
 
G

gcmarshall

Full Audioholic
in layman's terms, here is how i understand it...

a standard 15 amp circuit (look at your breaker panel to see if your theater room is a 15 amp circuit) can handle 1800 watts (voltsxamps=watts, so 120 volts, if you're in the USA, times 15 amps = 1800 watts).

each of your electronic pieces will list (either in the manual and/or on the back of the equipment) its max power draw, usually listed in watts, less frequently listed in amps. to be conservative (since these listed power draws are usually listed at max draw), i use the max draw for each device, add them up and see what that totals; you must include everything on that circuit - amps, receiver, subs, lights, ceiling fans, etc. your theater components may not ever reach these "max power consumption" numbers is daily use, but, again, i believe it's conservative to assume they will at some point when planning an electrical circuit for your setup. that leaves you with some cushion.

some beefy separate amps will eat up your entire 15 amp circuit all by themselves, if you're using its max power consumption rating as a basis for judgment.

if you have the option, have a licensed electrician install a dedicated 20 amp circuit (2400 watts capacity), if not for only your amp, certainly for all your theater components. this does not mean just adding a 20 amp outlet; there is a certain gauge (thickness) electrical wire that needs to be in the wall as part of the true 20 amp circuit.

my lawyer print.....i am not an electrician, nor can i certify if anything i have said above is stone-cold fact. consult an electrician, but i believe the basic math i have presented above is a good starting point.

depending on the max rated draw of the amp in question, combined with all the other gear you may/may not be running at the same time (plus lights, etc. that may/may not be on), you may be OK with a 15 amp circuit. this is about as much as i know. i have read elsewhere that your amp may not perform to its full potential if the electrical circuit is limiting its power supply. that may be something to consider and research further as well.
 
A

AndrewLyles

Audioholic
Well I apreciate the cander here GC. I'm learning why HT amps actually cost more than their pro counterparts has something to do with efficiency. A 7 channel Outlaw will pull something like 1400 watts while the 3 crowns will draw over 2100w. So my question is this then... I live in an apartment building in NYC so having the place reqired is out of the question. How do people power their entire systems if Amps pull so much of the power? I haven't added everything up yet, and won't until I get back from vacation, but have I been overloading my outlets for years and just been lucky? Granted I've never had dedicated amps before. Additionally, since I'm going to be using my Receiver as a Pre-Pro, and have it driving none of the speakers, how should I account for the power consumption... will it be substantially less since it is not having to drive anything? Sorry if these seem like silly questions,
~Andrew
 
Z

zumbo

Audioholic Spartan
I am a little over budget myself.

Yamaha RX-V1400 (500watts max)
NHT SW-12 (500watts max)
Adcom 7605 (1680 watts max)
Yamaha dvd (11 watts max)
Sony tv (165 watts max)
Digital cable box (80 watts max)

(2936) total. On a 20A circuit (2400). But all equipment is connected to a power conditioner that states (1800 watts max). So, I guess nothing ever runs at max, because I have had no problems. A couple of reasons I think may be that I don't use the amp in my receiver, and not all equipment is always on. I didn't list my CD & VHS because they don't draw much, and some of the other equipment would be off.

This may also be a good reason to use a 5-channel amp over a 2-channel and the internal amp of a receiver. As I stated, I don't use my receiver amp at all.
 
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WmAx

WmAx

Audioholic Samurai
AndrewLyles said:
Howdy All,
So I'm looking to add some amplicfation to my HT set up and am curious how to figure out if my outlets can handle the load that I am going to be placing on them. Potentially 3 x 2-Channel amplifiers (400w @ 4ohm), receiver being used as a Pre-Pro, TV, DVD,CD, perhaps a power conditioner or two, video game console, you know, everything that one would hook up to their own system in the living room. Any input is always appreciated.
~Andrew
I know that you saw the link I posted in another thread that you posted within, but I will repost it again for others who might not have seen that thread:

http://forums.audioholics.com/forums/showpost.php?p=132939&postcount=38

This relates to the maxmium continuous power potential. In real application, the amplifiers(unless they are class A) will use very little power on average. It is perfectly safe to plug those into a 15 amp 120VAC outlet. You will never need continous maximum output power in real application. This is limited only to test conditions. Please read through this thread for more information on the topic:

http://forums.audioholics.com/forums/showthread.php?t=14222

-Chris
 
ht_addict

ht_addict

Audioholic
Take a peek at my signature. With everything plugged into the same socket the total draw while watching a movie is 3.5A(440w):D
 
P

PENG

Audioholic Slumlord
gcmarshall said:
in layman's terms, here is how i understand it...

a standard 15 amp circuit (look at your breaker panel to see if your theater room is a 15 amp circuit) can handle 1800 watts (voltsxamps=watts, so 120 volts, if you're in the USA, times 15 amps = 1800 watts).

.
I have repeated this several times before, V*I=VA, not Watts. To get watts, you have to multipy V*I by the power factor. For an amplifier driving the average loudspeakers, the power factor could vary quite a bit but will most likely be less than 0.8. A 15A circuit is rated for 120VX15A=1800 VA. VA equals watts only for purely resistive loads, when power factor=1.

Some manufacturers specify their power consumption figures in VA, while others, e.g. some Denon receiver's power consumption figures are given in amps. If you multipy the amps by 120V you get the VA.

Many others specify their consumption in Watts, in that case you should assume a power factor of no more than 0.8. That is, inflate the watts by at least 1/0.8, or 25% to get the VA (that is, the often quoted VoltsXAmps number).

Example, if the amp consumes 1680 Watts, using the formula:

Watts=Volts*Amps*p.f., assume p.f.=0.8,
Amps=(1680/120)/0.8 = 17.5A

If you assume the p.f.=1, Amps=1680/120=14A.

The error resulted by ignoring the p.f. is not insignificant.

For practical purposes though, amps should rarely consume the specified maximum power. In fact, most receivers, such as Denon, Yamaha, Pioneer do not even specify a "maximum" number for their power consumption.

Also, a 15A circuit is rated for 15A continuous. For a short duration, it can do more. For a circuit to trip (or fuse to blow), you have to either exceed its rating by a little (10 to 20%) for a long time, or by a lot (say 50% or more) for a shorter time.
 
A

AndrewLyles

Audioholic
ht_addict said:
Take a peek at my signature. With everything plugged into the same socket the total draw while watching a movie is 3.5A(440w):D

Okay this is good to know. I looked at what Zumbo was running through his outlets too which makes me feel much better about running everything through the same outlet.
 
WmAx

WmAx

Audioholic Samurai
PENG said:
I have repeated this several times before, V*I=VA, not Watts. To get watts, you have to multipy V*I by the power factor. For an amplifier driving the average loudspeakers, the power factor could vary quite a bit but will most likely be less than 0.8. A 15A circuit is rated for 120VX15A=1800 VA. VA equals watts only for purely resistive loads, when power factor=1.
Power factor denotes the actual energy delivered to a terminated load(the speakers in this case). From what I can tell, power factor as discussed here has no important bearing so far as the maximum current draw the amplifier will exhibit becuase the amplifier has finite output abilities. For example: the amplifier is not going to produce more unclipped power into a reactive load than it would into a resistive one. The effective power delivered to the load is reduced, but the maximum voltage and current produced by the amplifer remains the same(or may be reduced if the amplifier has trouble with reactive loads). So, let's give an example where we have an AB class 100 x 2 amplifier that is 50% efficient. It will require 400 watts to produce it's maximum unclipped 100 x 2 watts into a resistive load(power factor=1). If the power factor of the terminated load = 0.7, the maximum power delivered to the final load will be 70 watts x 2. But the amplifier is not going to be able to increase it's power output beyond this without clipping. The amplifier is going to consume 400 watts with maximum from it's power source(outlet) with unclipped continuous output at 100 watts x 2 @ PF=1.0 or 70 watts x 2 @ PF=0.7. The power factor here denotes the actual output power delivered to a load by the amplifier.

Now, if you are talking about the power factor of the outlet vs. amplifier load on the outlet, then please provide data on the dynamic behaviour of this interface as power factor of the amplifier vs. loudspeaker load varies so that this data can be analyzed.

-Chris
 
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jcPanny

jcPanny

Audioholic Ninja
How much power do you need?

AndrewLyles said:
So my question is this then... I live in an apartment building in NYC so having the place reqired is out of the question.
~Andrew
Andrew,
Post the specs of your room, reciever, speakers, and other equipment. My guess is that you won't gain much from an outboard amp in your appartment over a good mid-fi receiver. By appartment I assume that your HT is not a 30x30 foot room and that you have neighbors. Thus, even if your had 2-300 Watts per channel available, you would not be able to take advantage of it without damaging your hearing and being evicted. What do you find missing from your current sound system? Perhaps you would benefit more from a speaker or receiver upgrade. What is your budget for the upgrade?

Concerning your power consumtion concern, identify the circuit(s) that your HT and other A/V eqipment are connected to. Flip this breaker and determine which additional outlets or lights are effected. Try to minimize the use of these lights and additional outlets when using your A/V gear. This will allow your A/V gear to use up to 15A without blowing the breaker.
 
A

AndrewLyles

Audioholic
jcPanny said:
Andrew,
Post the specs of your room, reciever, speakers, and other equipment. My guess is that you won't gain much from an outboard amp in your appartment over a good mid-fi receiver. By appartment I assume that your HT is not a 30x30 foot room and that you have neighbors. Thus, even if your had 2-300 Watts per channel available, you would not be able to take advantage of it without damaging your hearing and being evicted. What do you find missing from your current sound system? Perhaps you would benefit more from a speaker or receiver upgrade. What is your budget for the upgrade?

Concerning your power consumtion concern, identify the circuit(s) that your HT and other A/V eqipment are connected to. Flip this breaker and determine which additional outlets or lights are effected. Try to minimize the use of these lights and additional outlets when using your A/V gear. This will allow your A/V gear to use up to 15A without blowing the breaker.
jcPanny:
It's not so much that I am trying to get something extra out of my system. In fact when I moved to NYC I brought my equipment with me but had to leave my speakers behidn to to available space in the apartment and available space on the truck. I'm using a Pioneer Elite receiver THX-Select model from a few years ago that I have been rather happy with but the speakers I am looking at (Magnepan 1.6QR mains, CC3, and MGC surrounds) are 4-ohm speakers. I am thrilled with the flat/thin profile and the ability to mount the surrounds flush on the wall yet still have amazing presence and dynamic range for the money. Unfortuneatly my receiver cannot move 4-ohm speakers and I do not want to upgrade my receiver until I am ready for a full HDTV swich so that I will know all of the connectivity requirements I will need.

Since my receiver can be used as a pre/pro and export to an external amp I am learning that it is cheaper and from my understandig better to use a seperate powered amplifer to accomplish the task. That's pretty much the back story, and the more I have chatted with people here, especially helpful individuals like yourself and Zumbo, the more I am leaning towads an integrated multi-channel amplifier such as the Outlaw 7125 instead of stacking several 2-channel pro-grade amplifiers. I like the ability to remote switch on and off the amps with the receiver, the conserved space, and the more efficient power consumption of the multi-channel amps I have been looking at.

I was originally looking at the Crown amps becasue I am famliar with their products. I have used them in professional audio solutions for the past 10 years and have never been dissapointed by their sound quality, durability, or stamina n every situation. I liked the idea of the XLS-402 models so that there would be ample power, enough to adequately drive a rather inefficient speaker set without having to strain the amplifiers themselves. This is one concern that I still have with using the Outlaw amp on the magnepans as everyone I have spoken with says that the speakers require ample power. In my youth I used to engineer concerts and compete in Car Audio competitions, so I realize that I will not be needing the 1000's of watts of power that some individuals go after in there systems.

Ultimately, I want to put together a system that will completely engross a listener in movies, video games, and TV as this is 70% of what the system will be used for.

Seeing what people are running through the same outlet here, I do not think I am going to experience any serious dificulty with my set-up, but I did want to make sure that it was relatively safe to have this muchequipment through one breaker. As far as isolating lights from the A/V circuts, this could be pretty difficult as the apartment doesn't have that many different circuts, one for each room. Once everything is installed I will most likely need to set up a powerconditioning system, but one thing at a time I figure and deal with the problems as they arise so I don't end up going overboard when it isn't needed.
 
A

AudioSeer

Junior Audioholic
Magnepans are great speakers but I'm not so sure that they'd be my first choice for home theater. People usually use these for listening to Jazz & Classical. They lack the punch neccessary for rock or pop.

Also, Maggies need room to breathe. I don't think that you will be anywhere close to optimizing their performance by shoving them close to the wall.

Personally I would look at monitors that are specifically designed for close to wall placement. Many of the English brands sound good close to the wall. You are looking for a speaker with a front firing port or a sealed design.
 
A

AndrewLyles

Audioholic
AudioSeer said:
Personally I would look at monitors that are specifically designed for close to wall placement. Many of the English brands sound good close to the wall. You are looking for a speaker with a front firing port or a sealed design.

I've listened to a lt of different brands over the past year from Klipsch and Polk, to Def. Tech and Mirage. I auditioned several pairs of B&W's but what I found was that none of them impressed me. No offense to any owners out there but they didn't sound like imaculate speakers should. I realize that for $3-4k you're not going to get the top of the pile, but I would like something that when I hear, gives me goosebumps. For me, the Maggies did that, and I do realize thy need some serious room to breathe, its a concern of mine actually with the limited space I have, especially when sticking them in a corner. At the dealer I went to I only auditioned music the first time, but I am taking some DVDs with me when I drive back out to them in a couple of weeks. I'm hoping to push them into the corner and see if they still have the same effect on me that they did when I initially heard them.

I know that this is the wrong section for this question and I will open up a new thread in the loud speaker section, but what else is out there that makes your skin sizzle when you hear them?

Edit:
http://forums.audioholics.com/forums/showthread.php?t=17844
Here is the new thread on this.
 
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P

PENG

Audioholic Slumlord
WmAx said:
Power factor denotes the actual energy delivered to a terminated load(the speakers in this case). From what I can tell, power factor as discussed here has no important bearing so far as the maximum current draw the amplifier will exhibit becuase the amplifier has finite output abilities. For example: the amplifier is not going to produce more unclipped power into a reactive load than it would into a resistive one. The effective power delivered to the load is reduced, but the maximum voltage and current produced by the amplifer remains the same(or may be reduced if the amplifier has trouble with reactive loads). So, let's give an example where we have an AB class 100 x 2 amplifier that is 50% efficient. It will require 400 watts to produce it's maximum unclipped 100 x 2 watts into a resistive load(power factor=1). If the power factor of the terminated load = 0.7, the maximum power delivered to the final load will be 70 watts x 2. But the amplifier is not going to be able to increase it's power output beyond this without clipping. The amplifier is going to consume 400 watts with maximum from it's power source(outlet) with unclipped continuous output at 100 watts x 2 @ PF=1.0 or 70 watts x 2 @ PF=0.7. The power factor here denotes the actual output power delivered to a load by the amplifier.

Now, if you are talking about the power factor of the outlet vs. amplifier load on the outlet, then please provide data on the dynamic behaviour of this interface as power factor of the amplifier vs. loudspeaker load varies so that this data can be analyzed.

-Chris
Chris, we are talking about power/current draws from the wall outlet in this thread, right?

Take the Denon 3805 as an example, it specifies 120V 7.1A. That's great, no issues, so it draws 7.1A under whatever conditions Denon defined (but not published).

Now take that Adcom 7605 that Zumbo mentioned, 1680W, under condition "maximum" in this case. So at 1680W, if you assume a p.f. of 0.7, it will draw (1680/120)/0.7 = 20A. If you ignore p.f. and use what people constantly quoting the famous expression Watts=Volts*Amps, then the draw will be 1680/120 or 14A. This is enough difference to be noted. My point is, if you know the consumption in amps or VA (Sony, and I believe Yamaha use VA, then its fine to estimate how much it draws from the outlet, but for those who specify consumption in Watts (HK, Adcom, etc.), then you need to at least assume a nominal p.f. as an approx correction factor when trying to calculate its power draw from the outlet.

I don't disagree that for the amp/speaker circuits, p.f. is not going to be constant, but it would be safe to say that in most cases it won't average above 0.8.

Another point is, people often take the volts and amps, or VA numbers (again Denon and others tend to specify amps or VA), and interpret them as though they were Watts. For example, the 3805 would be interpreted as consuming 120X7.1=852 Watts. If you assume an overall efficiency of 50%, its output under that consumption, would be 426 Watts when it fact it is at least 20% less when you take p.f. into account.

Using your example of 100X2X0.7 (@0.7 p.f.)=140W, the power delivered to the load is reduced but the draw from the outlet is as you mentioned, still 400 (base on 50% efficiency as you mentioned), except that it is now 400VA, not 400W. The limiting factor here is the current, not the useful power. In other word, a 15A circuit can deliver 120X15=1800W only to a load with unity p.f. For a load averages at p.f. of 0.7, the 15A circuit can only support 120X15X0.7=1260W. At a given voltage, the power source, from the generator to the power line, cables etc., are ultimately limited by their current carrying capability.
 
WmAx

WmAx

Audioholic Samurai
PENG, I made a significant error in this conversation. I wrongly argued. I apologize for this error. For those following along with this thread: power factor entails more than reduced power to the terminated load. Power factor, while reducing the power absorbtion to the load, inversely increases the apparent power(VA) dissapation of the amplifier. This would, of course, mean that the VA of the wall circuit supply would be required to increase accordingly. I had completely forgotten this fact.

-Chris
 
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P

PENG

Audioholic Slumlord
Chris, you have nothing to apologize for. I have great respect for people like you who always stick to technical arguments yet never resort to innuendo or sarcasm that we sometimes witnessed around here. For those who don't mind technical arguments on controversial topics, I am thinking about starting a thread on bi-wire/bi-amp. I am just not sure if it belongs to this section. (Just found out there is one on the Loudspeakers and Subwoofers section)
 
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I

indcrimdefense

Audioholic
andrew,

i will leave the technical stuff to the experts. i have had numerous components on the same circuit, including 2 amps, a pre-pro, tv, cable box and dvd player with no problems whatsoever, and at times i have the sound crancked up. all of equipment was plugged into monster hts 1000, and never had any problems running out of power from the wall. i do use a 20 amp circuit, and at times run only the amp off the 20 amp circuit and rest of the components off a seperate 15 amp circuit, but i have not had any problems whatsoever with either configuration. unless your apt. has electrical problems, you will have the neighbors beating down your door long before you run out of electricity if your cranking it up.
 
A

AndrewLyles

Audioholic
indcrimdefense said:
andrew,
you will have the neighbors beating down your door long before you run out of electricity if your cranking it up.

I apreciate the honesty, and MANY MANY thanks to everyone who has been responding to this thread. Your knowledge and expertise has been incredible in helping me weigh my options.
 
T

tdeluce

Audioholic
I plug my Cinenova Grande 3 amp ( 600 watts x 3 into 4 ohms ) directly into
an isoated 20 amp circuit. I then connect everything else except my 1250 RMS
watt subwoofer ( gets pluged into a 3rd circuit ) into a Monster 3600
power center which is plugged directly into the second isolated 20 amp circuit.

Seems to be working fine...
 
nasd90

nasd90

Audioholic
Man am I glad I came across this thread.

I think I'm going to blow something when I get this all setup, though not sure if I have a big circuit or not. It's a big house but not new.

I'm just thinking off the top of my head...

JLAudio Fathom F112 --- has a 1500w amp in it.
Marantz SR8001 --- has a 875w amp in it (125x7)
Earthquake Cinenova 5--- has 1500w in it (300x5)

not to mention the DLP, XBOX, PS3, AppleTV, Harmony 1000... all plugged into a UPS.

Am I screwed ?

Nick
 

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