Dedicated Outlet and Amperage - Part Deux

polkatese

So, having had a 20 amps dedicated outlets (two: one of sub and one for the rest) for the past 9 years, I'd like to resurrect the subject again, for the sake of confirming or otherwise, the need to have 20 A breaker or 15 A. I ran into this very good posting and explanation on the merit of the choice:

Most amplifiers do not come close to the 15 amp limit of conventional AC circuits. Check the power supply rails fusing for the amplifier, it's probably rated at 3-10 amps - any tech familiar with the amp can tell you if you don't know or it's not mentioned in your owner's manual. If you have purchased an amplifier that exceeds the average, there's a fair chance you know what you have. Higher amperage does not flow to the amplifier simply due to the installation of a 20 amp circuit. The amplifier draws current as required by the speaker load and the demands of the signal. Just as with "watts" normal listening levels cruise along at very minimal amounts of current draw well beneath the peak capacity of the amplifier. Only on demanding and sustained peak levels of (typically) low frequency information such as organ pedals will the amplifier draw more than that "average" amount of current and it does so first from the power supply reservoir. It is only after that supply is close to drained that high current draw from the AC line would be required. Power supply caps can only refresh themself at a certain rate so it would be rather unusual for most amplifiers to test that 15 amp circuit. Not since the days of Phase Linear has a respectable amp manufacturer built an power amp that literally sucks current from the wall outlet. The ability of the power supply's capacitors to deliver amperage on demand is typically well within the requirements of a 15 amp circuit.

These conditions, of course, depend on your musical selections, your amplifier and your speakers along with just how loudly you prefer to hear musical peaks in your room. If your speakers are quite a demanding load on the amplifier (low electrical sensitivity combined with low impedance points combined with high electrical phase angle) at those frequencies which ask more than "average" levels of power, then the higher the amperage you can provide to the amplifier via the AC circuit will be appreciated. Probably about 1-2% of all "audiophiles" own such components. Again, you should know whether you have demanding loudspeakers and whether you have purchased an appropriate amplifier for such speakers. You should certainly know the sensitivity of your speakers and how loudly you prefer to listen. You should also know whether you are frequently clipping the amplifier's outputs though clipping does not clearly translate into a need for current. If you listen at rational levels to the majority of music, there's a good chance you'll never even come close to the limits of the amplifier or the AC circuit even with more difficult loudspeakers.

If you are running a tube power amp with a pair of 16 Ohm Lowthers, you do not need a 20 amp circuit. The vast majority of amplifiers of any configuration do not require a 20 amp circuit. Contrary to what has been suggested here, there is no reason to believe the installation of a 20 amp circuit or using a 20 amp power cable for an "average" system will provide any audible improvements. On the other hand, a dedicated circuit itself will improve performance, but not just the difference between a 15 and a 20 amp power cable of the same construction. Consider also that a higher amperage capacity in the cable will imply a heavier gauge which will be less flexible and will require more manipulation during installation. If there are any audible improvements between a 15 and a 20 amp power cable, they would be attributed to something other than the gauge of the cable.

In this case, you have a power conditioner between your AC outlet and your system. The AC power conditioner will not care whether you have a 20 amp circuit or cable if it is limited to 15 amps. Even if the pwoer conditioner's manufacturer has tried to impress you with 20 amp outlets on the unit, your amplifier and speakers - along with your musical choices in your room size - will determine how much current capacity is required. Overkill just for the sake of overkill is up to you but IMO it is less than stellar thinking. Work with the demands of your system and don't try to play doctor on TV. Your CD player and DAC are unlikely to draw even a mere 3 amps.

I have run the power through Panamax 5500 all this time, and the meter reading NEVER exceeds 8 amp. In other words, my wife would have posed a much more immediate threat (of calling the cops to escort me out of the house) before I experience 15 A spike or otherwise. So, the answer above, IMHO, have a lot of truth and wisdom. Just a side note, the meter reads between 4 - 6 amps in most (I'd say 95+% of my listening and watching movies times in the past 9 years). Btw, I have a monstrous power amp capable of 400 watts @4 ohms speaker load all 7 channels driven (if ever). So, my conclusion is that the wisdom of having DEDICATED OUTLETS is much more important than the need to have 20 amps rating (as I bolded above).

What say you, who have dedicated outlets?

F1nut

On the other hand, a dedicated circuit itself will improve performance

I agree because you no longer have other items generating noise in the circuit, the noise floor will be lower.

disneyjoe7

My take on this subject...

A 20amp outlet needs to be wired with 12g wire, where a 15amp outlet needs to be wired with 14g wire. So 8amp draw will drop more voltage from the breaker to the outlet with a 15amp circuit then would a 20amp circuit. In the end a cleaner, steadier voltage to the equipment and in turn a better audio signal.

Then see it like this if a normal outlet with is a 15 amp outlet, just how many other outlets are working on this circuit? Just how many other connections are there? Then just how much other noise are the other outlet on a non dedicated circuit is given you on that outlet?

DarqueKnight

"If you listen at rational levels to the majority of music, there's a good chance you'll never even come close to the limits of the amplifier or the AC circuit even with more difficult loudspeakers."

The statement above would more correctly be stated as:

"If you listen at rational levels to poorly recorded music with low dynamic range, there's a good chance you'll never even come close to the limits of the amplifier or the AC circuit even with more difficult loudspeakers."

Well recorded music with high dynamic range has many small duration peaks (transients) that can draw large amounts of power. These transients last for fractions of a second, but they are audible, depending on the resolution of the audio equipment and the listener's hearing. Transient content adds a lot of "lifelike" quality to recorded music.

It is possible for some high power amplifiers to pull in excess of 100 amps through a 20 amp circuit. The breaker won't trip if the transient lasts for a short enough duration of time (typically thousandths of a second). The principle is the same as people who have been struck by lightning and not been injured because the current passed through them so quickly that their body wasn't heated by the high current or people who walk barefoot across hot coals without getting burned if they walk fast enough.

PS Audio's P10 AC regenerator is rated for 70 peak amps. However, it can't meet the peak current demands of my JC 1 power amps, which are capable of 135 peak amps. The wall outlet is capable of supplying the full 200 amp rating of my home's electrical service...for short durations. PS Audio advises that their AC regenerators are not able to meet the current demands of some power amplifiers. This is because the regenerator is limited to its peak current rating whereas the wall is limited to the rating of the electrical service, which is 100 usually amps or more.

You don't "need" a 20 or 30 amp dedicated circuit just like you don't "need" a high powered amplifier or a high powered car or a 100 inch screen to watch movies at home. The vast majority of home audio amplifiers are designed to work on 15 amp non-dedicated circuits.

polkatese

Good discussion guys. Btw, I noticed that PS Audio PowerPort Premier is OOP, what's the deal?

DarqueKnight

The Soloist in-wall power conditioners are also OOP. PS Audio decided to narrow their product focus and get out of the premium receptacle market.

steveinaz

I have never had dedicated nor anything above standard 15amp outlets powering my equipment, for over 35 years, and have run some BIG amplifiers---never had an issue. FWIW. Do I think a dedicated circuit would be better? It certainly wouldn't hurt.

tonyb

Me neither Steve, but there are some monster amps out there that would need it but thats outside the norm. A lower noise floor, any gear could benefit from that.

polkatese

Steve, have you thought about it? For practicality reason, I like the convenience of being able to turn off my gear from one switch when we are going on vacation. And with the occasional power out during Santa Ana wind season, I cringed when it went through power cycle popping from standby, off, on, standby.

No curiosity to try dedicated outlet Steve?

steveinaz

Oh yeah, If we build again I'll definitely have a dedicated circuit run; why I didn't think about it on our current house---I don't know. I guess I was overwhelmed with other stuff when we were deciding on cable drops, phone drops, colors, etc.

disneyjoe7

polkatese wrote: »

Steve, have you thought about it? For practicality reason, I like the convenience of being able to turn off my gear from one switch when we are going on vacation. And with the occasional power out during Santa Ana wind season, I cringed when it went through power cycle popping from standby, off, on, standby.

No curiosity to try dedicated outlet Steve?

You're not safe to just turn off the circuit breaker. There's a capacitance between contracts when a lightening storm it can skip over the break circuit which is off. You're best to unplug everything.

dkg999

Even 15 amp circuits should be wired with 12g. 14g is OK to go from a switch to a light, etc.

polkatese

One thing that I observed on the subject of dedicated outlet for our gears: every single licensed electrician that I have talk to (perhaps a total of 4 over the past 10 years) who came from different backgrounds, but all are properly licensed and do big and small projects, they all questioned me the need of putting in 12 AWG and 20 Amp breaker on a dedicated outlet, without exceptions. The guy who did mine questioned it but did it anyway since I insisted. So, I guess unless you do it yourself, you will have to explain or insist.

Doug, all of the production homes (i.e. non custom) in the state, by law, is required to use 14g for convenience outlets (daisy-chained) except kitchen area and bathroom. Or perhaps, minimum requirement a better term to use, although the electricians might use the word as is (this was explained to me, and I haven't done any research or reading on this).

Dennis Gardner

I thought that putting multiple 20 amp circuits in your system was like discussing girth in addition to length.......

disneyjoe7

polkatese wrote: »

One thing that I observed on the subject of dedicated outlet for our gears: every single licensed electrician that I have talk to (perhaps a total of 4 over the past 10 years) who came from different backgrounds, but all are properly licensed and do big and small projects, they all questioned me the need of putting in 12 AWG and 20 Amp breaker on a dedicated outlet, without exceptions. The guy who did mine questioned it but did it anyway since I insisted. So, I guess unless you do it yourself, you will have to explain or insist.

What gauge of wire did they suggest for a 20 amp breaker to a dedicated outlet? I hope 12 awg or above, and not 14 awg.

polkatese

12g on 20a and 14g on 15a, Steve.

disneyjoe7

Ok that's what I stated before.

polkatese

Steve, I think you should splurge on this: http://www.dedicatedaudio.com/inc/sdetail/109/33780

F1nut

polkatese wrote: »

One thing that I observed on the subject of dedicated outlet for our gears: every single licensed electrician that I have talk to (perhaps a total of 4 over the past 10 years) who came from different backgrounds, but all are properly licensed and do big and small projects, they all questioned me the need of putting in 12 AWG and 20 Amp breaker on a dedicated outlet, without exceptions. The guy who did mine questioned it but did it anyway since I insisted. So, I guess unless you do it yourself, you will have to explain or insist.

I told my guy to use 10 gauge. All he said was ok.

kuntasensei

Just want to add: When I bought my Adcom GFA-5503, I was concerned that I was running too much equipment on my living room circuit. I never had one of those "dimming the lights" moments, but I was still worried that I was pushing it by running all my equipment except my projector off of one receptacle. I recently got a Belkin PF60 power center to hook all my gear to, and threw in some really loud movies to see just how much I was pulling when my 1,000w amp and the Adcom's 600w was going full steam. To my surprise, even during ridiculous moments of room-pressurizing bass, it never drew more than 8.2A. That was with my AVR, both amps, a Blu-ray player, a cable box, an EQ, and my backlighting going... with 9.2 surround engaged.

Played War Horse the other night at -10dB from reference for some friends and saw it hit 9A during the battle sequences, which have a ton of mortar fire and deep-trolling explosions (and I will likely never play the system that loud again). Since the only other things on that circuit are my projector and a ceiling fan that rarely sees any use, I think I'm okay.

mmmalmberg

I know it's late in the conversation but, as far as I can figure, a "dedicated circuit" is still connected to all the other circuits in your house wiring system; the panel doesn't have any special isolation or anything - as long as the breakers are closed, I don't believe you're isolating yourself from any noise. Having a power conditioner is what will make the difference when it comes to line noise.

Moose68Bash

mmmalmberg wrote: »

I know it's late in the conversation but, as far as I can figure, a "dedicated circuit" is still connected to all the other circuits in your house wiring system; the panel doesn't have any special isolation or anything - as long as the breakers are closed, I don't believe you're isolating yourself from any noise. Having a power conditioner is what will make the difference when it comes to line noise.

What would happen if an adequately sized isolation transformer were placed in a dedicated circuit? Would that help eliminate line noise from other circuits in the house?

tonyb

mmmalmberg wrote: »

I know it's late in the conversation but, as far as I can figure, a "dedicated circuit" is still connected to all the other circuits in your house wiring system; the panel doesn't have any special isolation or anything - as long as the breakers are closed, I don't believe you're isolating yourself from any noise. Having a power conditioner is what will make the difference when it comes to line noise.

Have to disagree here. When you use a dedicated line, you remove other things that cause line noise like lights, appliances, heat/ac units, etc. Yes power conditioners can lower the noise floor too but for the best possible outcome I would think a combination of both PC and dedicated circuit would be optimal.

hewlew1

I would think an isolation transformer would reduce noise in what ever piece of equipment was plugged into it. Dedicated circuit or not would make no difference. I dont believe it would benefit other areas in the house.

mmmalmberg

tonyb wrote: »

Have to disagree here. When you use a dedicated line, you remove other things that cause line noise like lights, appliances, heat/ac units, etc. Yes power conditioners can lower the noise floor too but for the best possible outcome I would think a combination of both PC and dedicated circuit would be optimal.

How does that happen? I.e. how are those other things removed?

CoolJazz

What the dedicated line does is provide isolation. How??? Yes it's tied to the same circuit. So wire goes from your equipment thru the breaker panel to your refrigerator. But the key is the impedance.

At the close by to your house transformer, you have an extremely low impedance source feeding your house. The guage of wire to your home still maintains a decently low drive impedance. So at the breaker panel, with tight fittings, you have a nice low impedance. Now the long wire running across the house, usually through several joints at wall outlets, gets further and further from that low point. So if you impress noise on the line at the stereo, it gets less and less along the wire. If you could measure it every little ways going back down the wire towards the panel, the disturbance would get less and less until at the panel it'd be all but gone.

Because of the low impedance at the panel, you'd have to present some really nasty noise to get it back through the panel to other circuits. Yes, it does to some degree, depending greatly on the situation of how low impedance it is at the panel depending on the wire size, the power draw, tightness of all fittings etc.

So dedicated lines to your stereo do indeed provide a significant advantage!

Now the dirty secret....the noise you're probably in need of paying attention to may not be from further awy but the noise created right from your own system! Switch mode supplies in particular really create a LOT of power line garbage! You have one creating nasties if you have a TV hung on the circuit. CD players certainly! And even decent traditional supplies typically do little to avoid impressing noise back on the supplying feed. So that's where the local noise filters, including isolation transformers, come into play. And if you've introduced a typically very noisy UPS into your stereo system, then you certainly need to provide filtering for best results!

CJ

DarqueKnight

mmmalmberg wrote: »

I know it's late in the conversation but, as far as I can figure, a "dedicated circuit" is still connected to all the other circuits in your house wiring system; the panel doesn't have any special isolation or anything - as long as the breakers are closed, I don't believe you're isolating yourself from any noise. Having a power conditioner is what will make the difference when it comes to line noise.

mmmalmberg wrote: »

How does that happen? I.e. how are those other things removed?

A certain amount of electrical noise is delivered with the utility service. The noise content is diluted when it is distributed from the breaker panel over separate circuits. When it comes to noise, whether it is acoustic noise or electrical noise, distance from the noise source has isolating effects. Dedicated circuits move the devices connected to them farther away from the main source of electrical noise (the breaker panel).

Moose68Bash wrote: »

What would happen if an adequately sized isolation transformer were placed in a dedicated circuit? Would that help eliminate line noise from other circuits in the house?

Yes.

tonyb wrote: »

Have to disagree here. When you use a dedicated line, you remove other things that cause line noise like lights, appliances, heat/ac units, etc. Yes power conditioners can lower the noise floor too but for the best possible outcome I would think a combination of both PC and dedicated circuit would be optimal.

True. I could hear a difference with only a dedicated circuit. Passive power conditioners and AC regenerators provided further improvement.

rpf65

Just my 2 cents here. One of my winter projects will be running a dedicated plug. The reason for this is to plece the plug directly behind the stand holding all of my HT stuff. Since I'm going through all of this trouble, I'll use industrial grade 20A plugs, a 20A breaker, and wire it with 10/2 wire. The reason I'll do this is because it will cost about $40 more, I only want to do this once, and 10 AWG wire is coded for 30A.

The truth of the matter is, if I were building a house, I probably wouldn't have anything smaller than 12 AWG wire, or 20A outlets anywhere. It wouldn't be do to any performance issues. I personally think a good conditioner will do a thousand times better job than wire. Just an after thought, I never buy electrical fixtures or plumbing fixture from hardware/big box stores. The quality isn't there, in comparison to dedicated suppliers.

zane77

When I had my house built, I installed a dedicated 20 amp breaker for my sound system with 10 gauge wire but I also installed all 20 amp circuits throughout the house with 12 gauge wire. I'm really glad that I did this. The only 14 gauge wire I used was for the smoke detector circuit. I did all the wiring myself so I know where everything is insatalled in the walls and ceiligs. I think a dedicated circuit for your sound system is a must.