@peter_s Synergistic Research’s latest “Purple” (it is actually black) duplex receptacle is an isolated ground type.
All this focus on dedicated lines, wire gauge and breaker size makes me think it would be beneficial to remind everyone about the importance of having a good grounding system. We just moved into a 17 year old house a few months ago and I could not locate the existing outdoor grounding setup to the main panel which concerned me. This week I had an electrician install new ground rods and large gauge copper conductor connecting them to the main panel ($375). It was done per NEC and local code. I was not expecting any effect on the sound quality of my system, but I was shocked at the improvement in lowering the noise floor and the elimination of a slight-but-annoying glare on female vocal peaks that I have been wrestling with. Another unexpected bonus was that my wife commented that night about how much better the picture was on our plasma TV. Definitely great bang-for-the bucks!
I then starting researching grounding systems and found out that the life expectancy for a copper-over-steel-bar grounding system is only 5-10 years!
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Not so for audio equipment power transformers. If voltage drops so does current as well as wattage, (VA)... In the case of a power amplifier lower wattage, lower power...
Thank you.
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Another question sort of related to the dedicated circuit topic:
either here or on AA I once read something to the effect that the class D of most powered subs would "dirty up" the power for whatever other audio component was on the same circuit. I apologize if I am misquoting this, this is a rather foggy subject for me.
So my questions are: is there any truth to that, and if so, I guess that means your sub should be out there on it's own island?
I am currently running my amp on one circuit, my pre and my CD player on another circuit, and due to what I typed above being stuck in a cloudy recess of my brain, I have my sub on it's own circuit. . . .
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Current doesn’t always go up when voltage goes down, it’s a little more complicated than that.
That is true. For AC induction type motors if voltage goes down due to Line voltage drop, current go up.
Not so for audio equipment power transformers. If voltage drops so can/does current as well as wattage, (VA)... In the case of a power amplifier lower wattage, lower power...
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Current doesn’t always go up when voltage goes down, it’s a little more complicated than that.
I agree with your statement, and my explanation of it probably wasn’t as specific as it could have been, but I didn’t want to get too crazy with theories, formulas and examples. Anyone is free to supply some if they wish.
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Current doesn't always go up when voltage goes down, it's a little more complicated than that.
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@bigtwin
If a train leaves New York travelling at 60 MPH, and a Hot Air Balloon can accend at a rate of 5 feet per second when the ambient air temp is 78.3 degrees, can I still hear any difference between a 12 gauge 15 amp line and a 10 gauge 20 amp line, when playing side two of Zappa’s Burnt Weeney Sandwich LP?
Depends on if you’re sitting in the sweet spot or not, when the last time you cleaned your stylus was, and if you're listening to the Japanese pressing or not. 😎
Thankfully I can also have a sense of humor about this stuff.
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PS - I have a modest 120W/channel integrated amplifier on a Furman AVR which lets me monitor line voltage AND see instantly if the taps are switching to compensate, as @dpop imagined amps do (they don't, but an AVR does!) . I echo the sentiments that while the inrush current can cause significant sag, during actual playback actual current needs are small and I rarely see more than 2 V of AC line voltage fluctuations, even with the TV and Home Theater receiver feeding off the same line too.
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Hey @dpop
While you are correct that Watts = V * A, the way linear amps work (with the exception of Sanders' Magtech) is that the rail voltages WILL sag if the line voltage sags. There's no adjustment feature without a voltage regulator such as a Furman with an AVR feature.
Does this sagging matter? Well, possibly. I think this would be a good case study for Amir to do, to compare output linearity with input AC voltage on a linear amp. Due to the way current amplification works, and moderate amounts of feedback we normally pretend it doesn't.
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If a train leaves New York travelling at 60 MPH, and a Hot Air Balloon can accend at a rate of 5 feet per second when the ambient air temp is 78.3 degrees, can I still hear any difference between a 12 gauge 15 amp line and a 10 gauge 20 amp line, when playing side two of Zappa's Burnt Weeney Sandwich LP? Feel free to discuss ad nauseam. 🤣
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@dpop okay, I can happily live with that!
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One topic that doesn’t get discussed much is available voltage. The rule of thumb is that what voltage can’t accomplish, current will (I know I’m probably getting a bit technical here). So let’s take that USA goal of providing 120 volts at an AC outlet, and you are measuring or only providing 115 volts (this can sometimes take place during hot air conditioning days in your neighborhood or building). Your amplifier could in reality pull more amps on peaks (compared to providing it 120 volts), due to the fact that you’re providing a lower AC voltage to it. This is when voltage drop becomes part of the equation. I guarantee that in most situations this won’t ever be a problem, but it is something to consider, especially with longer runs of AC wiring to the outlet from the circuit breaker box (technically called load centers). Again, this is normally not a big concern in almost all installations, except for some, but at the same time, it is worth noting. Here are a few examples of voltage drop charts:
Cerrowire Voltage Drop Chart
Voltage Drop Chart
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FWIW:
@kijanki
+1
Please explain what happens if the power transformer’s secondary winding voltage is lower feeding the rectifier, due to a quick AC mains VD event, and the electrolytic capacitors voltage is higher. Just going from memory the rectifier will not conduct and the caps do not get recharged for that "(millisecond pulse)" in time.
Jim
Response:
@jea48 You are right - there will be no current thru rectifiers until capacitor voltage will drop below rectifier supplied peak voltage. Theoretically it is possible to build LPS where capacitors keep average instead of peak voltage, but it requires huge inductor in series (in order of Henries) made with thick wire and AFAIK nobody is doing it. One problem is lower rail voltage (average instead of peak) while the other is dependency on the load current.
http://www.r-type.org/articles/art-144.htm
I prefer Aluminum armored solid conductor 10 - 2 with ground MC (Metal Clad) cable for branch circuit wiring. MC NOT AC metal clad cable.
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@immatthewj
did the work boxes in between them and the outlets degrade them and does it affect them that each as two other outlets that are not being used?
I know some audiophiles really like to dissect every morsel of an AC circuit for audio, but in your case, I wouldn't sweat it. IMO, they're still considered dedicated circuits. Some with golden ears may not agree with that, but that's my opinion.
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Thanks for that @dpop , I decided to do 3 dedicated circuits about 25 years ago. I didn’t know then and still don’t know a whole lot about this stuff, but I used to work with a bunch of shade tree carpenters & electricians & I bought a book about basic home wiring. I put the outlets in and ran the 12-2 runs of Romex, and then I paid someone to install an upgraded box and connect my new circuits.
However, my stupid question is: in the course of living in our house, I found the need to relocate outlets. Twice, actually. I asked around (including the electrician people at Lowes) and I was told that it was legitimate to use a work box to create a junction in the dedicated circuit. So the two questions are:
1) was this actually a legitimate thing to do?
and
2) the three circuits are still dedicated in that there is nothing on them but my audio components, but did the work boxes in between them and the outlets degrade them and does it affect them that each as two other outlets that are not being used? Does that last question even make sense as written?
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@immatthewj
Isn’t one of the selling points of a dedicated circuits that other loads are eliminated which would dirty up the power to your audio components? Not necessarily that you have more current available, but "better" current?
There’s plenty of arguments and discussions to go around. Power conditioners aside, the basic requirement or need is the ability to provide a path of least resistance for AC power transfer from your circuit breaker box to your amplifier(s). How you accomplish that is up to you or your electrician. It is most times accomplished via dedicated AC circuits, with no other appliances or devices on them. That keeps them "clean" and able to deliver the maximum amount of current and voltage needed. Over-sizing can increase this capability.
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@mesch
Does anyone know of an amplifier that would require greater than a 15 amp curcuit? By this I mean one that even for a mil sec would draw 15 amps?
Only an in-rush current ammeter will provide this true information. If you don’t own one, you’ll never know for sure, even by reading the ratings specs of the amplifier itself. The amperage draw of an amplifier under question will vary depending on a) voltage available to the amplifier (in the US, 120 volts should be the goal) b) minimum current requirement of the amplifier c) amplifier operating with load (speakers being used) d) material being played through amplifier e) at what volume level amplifier is driven.
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Isn't one of the selling points of a dedicated circuits that other loads are eliminated which would dirty up the power to your audio components? Not necessarily that you have more current available, but "better" current?
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Does anyone know of an amplifier that would require greater than a 15 amp curcuit? By this I mean one that even for a mil sec would draw 15 amps?
Unless of course it became defective hence the need for the breaker. Likely a 15 amp breaker will do for any amplifier. Likely the safeest.
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@cey Wrote:
man, thats cool. i been thinkin of doing that for a good while. i wont have the time any soon, but hopefully ill get around to it next year.
See article below:
Mike
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OP,
Just out of interest did you notice any change when you swapped the 30a breakers for 20a?
I don’t remember if I have 15a or 20a. I thought everyone actually knows it has nothing to do with the actual current required by components. At least for normal systems.
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@bigtwin
Thank you for verification of my comments. Sadly it won't make much difference on this forum.
I realize that, but sometimes I like to give it another try. It's also all about educating one on the subject too. I'm still learning myself, but like to sometimes pass along what I have learned.
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@8th-note
You’re definitely on the right track, and probably more knowledgeable than most. When planning for audio AC circuits, it’s best when you can calculate your amperage capacity needs (in advance if possible). When it comes to audio needs, metering definitely helps in this area, with a knowledge of electricity as well. Establishing four dedicated 20 amp circuits for one’s audio system may be considered overkill for some, but may be a requirement for others. Yes, when lights are dimming when playing your system, there is some kind of starvation taking place, and in need of an inspection, improvement and probably upgrading.
I don’t claim to know everything, but I’m at least very familiar with grounding (for lightning especially), bonding, and wiring current capacity. I would agree with you on voltage drop for long distances of wiring. Those voltage-drop tables can easily be found on the internet, but probably not necessary in the home environment. Many audio-enthusiasts tend to favor delivering AC to their amplifiers via 10 AWG (as I too do the same, and have implemented it as well), but many electricians may not want to provide that for you, as I believe it doesn’t typically pass code (10 AWG on a 15 or 20 amp circuit breaker). I think someday someone needs to update the code for this application, as they have in the past with/for balanced AC power. It’s very easy to go to extremes when providing AC power for audio systems, but sometimes it’s simply not always necessary.
Do We Need Hospital-Grade Receptacles?
What exactly does "Hospital Grade" mean?
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Excellent discussion and very informative. I am in the early stages of building a house and I've been researching the electrical options for my dedicated listening room. I'm certainly no expert but here are a few things that I think I've learned along the way. Please correct me if I get any of this wrong (I'm sure you will!).
One of the advantages of a 20 amp circuit is that code calls for the wiring to be larger. This should allow for a smaller voltage drop from your breaker to your outlet than a 15 amp circuit. If the service panel is close to the outlet this isn't an issue but in cases where there is a long run it could make a difference. I don't know how much difference a few volts make but I understand that higher voltages are better. This would indicate that for the marginal extra cost a 20 amp circuit would be better even if it won't be supplying high wattage components.
A few decades ago I was powering a pair of Large Advents with an Adcom GFA 555 and the lights would dim during bass transients. This was in a relatively modern house (70's vintage) on a 15 amp outlet. I installed a built in cabinet for the stereo equipment and included a new 20 amp circuit. The dimming stopped.
If you run a large Class A amp it might use more power than you think. I bought an inexpensive watt meter to measure my Krell KSA 300S and found that it uses about 1000 watts at idle and about 1700 watts when it hits the highest bias level. Fortunately I have a 20 amp outlet to plug it into (the guy who built my house was an electrician) but I would not want to run this beast on a 15 amp circuit.
At AXPONA several years ago I met Caelin Gabriel from Shunyata in their room at a slow time (really nice guy BTW). We talked for quite a while and I picked up a few tips - one of which concerned outlets. Caelin very candidly told me that Shunyata's outlets are great but if I wanted to be more cost effective a Hubbel 5362 was very good for a lot less money. I bought one (Amazon) for my 20 amp circuit and it is obviously better built than the contractor outlet. He specifically advised me not to use hospital grade outlets. These outlets are made of stainless steel which does not conduct electricity as well as copper. They are designed not to corrode in an environment where strong cleaning chemicals are used regularly. Since the medical instrument field is one of his big markets I figure he knows what he's talking about.
For the new house I'm considering a separate custom panel for the listening room similar to what Fremer did with his room (I would even use the same contractor for the panel). If anyone has done this I would like to learn from your experience.
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@dpop Thank you for verification of my comments. Sadly it won't make much difference on this forum. What we have here are a lot of people who also "feel" how much better thier cars drive just after they've washed them. 😂 I read an article some time ago that answered why politicians continue to repeat a lie, long after it has been debunked. Studies show people are much more receptive to any message that supports a current belief (no pun intended). In order to accept any message that contradicts a current belief, a person must be willing to analyse new information, accept that they could have been wrong in their prior convictions and change their position. Research shows that many people are simply unwilling or unable to do this. Not to get political here but Trump supporters who contiue to believe the election was stolen is a classic example of this. The insistence that over building our power supplies is just one more?
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Posting this from another thread I contributed to, and I realize some won’t be able to technically grasp what I’m discussing here:
For decades I have read about how many audiophiles have wanted to establish dedicated large gauge wired circuits with hundred dollar wall outlets, or power conditioning, to provide every milliamp of power available from their AC service to their speaker amps. I’m all for that, as I do the same. I get that. What I have a hard time understanding is that, IMO, it’s most times already there, without spending thousands of dollars on power conditioning and heavy gauge wiring. As I continue on, feel free to tell me what I’m missing here, and I’ll try to understand.
I think I know a little about AC for audio, so let me try to convey my thoughts here. First off, I hope everyone here is familiar with in-rush current. For those that aren’t, this is a momentary need for a large amount of current when an inductive device turns ON (for example, a refrigerator, dehumidifier, or air conditioner, etc.). Many times these in-rush values are in the 30-40 amp range, being pulled from non-dedicated 15 or 20 amp circuits (ie, there are other electrical devices on the same circuits). When this in-rush current takes place, not only are these spikes ignored by typical home circuit breakers, but the in-rush amps are almost always delivered on typical 15 and 20 amp wiring and circuits. If the wiring or circuit breaker wasn’t able to momentarily deliver this high current, your refrigerator, dehumidifier or air conditioner wouldn’t turn ON. IMO, momentary peak amplifier current draw could also be considered in-rush current.
I have an ammeter that is able to measure in-rush current (many ammeters aren’t capable of that). Since the conversation is revolving around improving home wiring for audio systems, I think this is the first time I ever placed my ammeter (set for measuring in-rush current) on my main audio system amplifier AC feed, while playing the passage of cannons on Telarc’s Tchaikovsky 1812 Overture CD (where they warn you that speaker damage can occur if you’re not careful when playing that passage in the song).
The ammeter was clamped on to the AC feed that provides power to my three Crown Com-Tech 400 Amplifiers (which are rated at 220 watts per ch. into 8 ohms). This particular system (I have a few in my house) is a tri-amped system, with an active 3-way crossover. The ammeter was only attached to the amplifier power feed. The circuit for these amplifiers is a dedicated one, with a 10 AWG 15’ cable running from the circuit breaker box, connected to a 15 amp circuit breaker in the load center. The 10 AWG terminates (with correctly torqued AlumiConn wire connectors/nuts) to a Tripp Lite Isobar Ultra surge protector. To soften the in-rush to the amplifiers during turn-on, I also employ a 10 amp rated variable autotransformer (aka variac), fed from the Tripp Lite Isobar Ultra.
So what I found was that when I initially turn ON the power switch on the autotransformer (without applying power to the power amps), an in-rush of 10. 3 amps occurred (that value is not always consistent, depending upon how recently the autotransormer was powered up, as it stores energy for a short period of time). After clearing that figure, I applied 120 volts to the amplifiers. As all three amplifiers sensed this voltage, they turned ON. The total in-rush current of these three amplifiers turning ON was 15.32 amps. Clearing the ammeter reading, I then played the cannons passage on the Telarc CD. I’m not sure if you’ve ever heard this CD (Telarc 80041), but when the LP came out (I have that too), it was monumental, as it was one of the few recordings that was able to record these extremely loud cannons, and transfer it to vinyl (later to CD). If my amplifiers were ever going to draw peak power, it would definitely be while playing these cannons. So with my speakers blaring, the peak power consumed by all 3 amplifiers during this passage was only 1.85 amps. I admit, I expected a value that was going to be higher, for the amount of bass that my 15" bass drivers produced.
So from my POV, your home circuits are already able to deliver lots of peak amperage when needed. Improving on that I get, but I’m not sure there really is a need for some, when peak power is probably already there when needed.
Recording of October 1979: The Telarc 1812 Overture
What is resistive load appliance? What is inductive load appliance?
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@builder3
I think you misread. He states that the components have robust power supplies. I would interpret that as the build of the transformer, rectifiers and filter caps.
He's also stated his amp is on a different circuit. 15A for source components is plenty.
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A 15A breaker for an electrical outlet is anything but a 'robust power supply'. It's code minimum, regardless of the wire gauge.
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I believe in isolation of power to my audio system. I installed 3 dedicated lines for my system. I used 10ga romex for amp, 12 ga for preamp and another 12ga for digital. I used 20amp breaker for the amp and 15 amp breakers for the other two lines. All my components have robust power supplies supplying the needs of the audio curcuits therin. I believe the current supplied is more than sufficient. Also used hospital grade outlets for all lines. Lines are rum off a subpanel that, in addition, only serves bedroom outlets and lights.
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If I recall, the Carver subs substituted power for size, so a ferocious amount of power was demanded. Not that surprised. :-) A large diameter sub would fix that.
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Voltage drop allowances are not even a NEC requirement, I know I've had voltage drop with my system when I used a carver subwoofer for a short time, even with 20 amp dedicated circuits using 10awg wire.
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I, too, waited too long to upgrade the electrical path. Skeptical of SQ improvement. Well worth it. Hearing is believing. Especially if your system is true to the source.
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@bigtwin
+1
Very good comments. I have been an advocate of high quality AC power for audio components for a long time. I have also recognized that the need for ultra high current capability is grossly exaggerated when discussed on audiophile forums. People take it too far and over the top.
You and @dpop provide very rational examples and explanations as to why there’s no need or supportive evidence to go overboard with regard to having sufficient amounts of electrical current available. The “headroom “ argument can be over inflated.
Charles
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I would like to hear peoples recommendations on duplex receptacles, compatible with isolated ground circuits.
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It would appear that many many people on this site, while knowing a lot about stereo equipment, don’t have a real grasp on basic principles of electricity. A circuit breaker is a saftey device that limits the maximum flow of current draw on the individual circuit. A 20 amp breaker will trip if a sustained draw exceeds 20 amps. Its actually suggested a breakers reliable safe constant draw is 80% of it’s rating. 20 amp breaker can safley handle a constant draw of 16 amps without tripping. Momentary spikes well above 20 amps are not likely to cause an issue. The gauge of your wire is rated for the maximum current it can safley handle without overheating and becoming a fire hazard in your home. 12 guage wire is rated for 20 amp srevice. Again, momentary spikes are not an issue. The total current/amperage draw of your total system, running on the same circuit, determines your power needs. Many will be surprised at how little current your system actually requires. Especially if it’s solid state equipment. For example, I have two Hegel H30 mono blocks , 1150 wstts per side @ 8 ohms, two Rel S/812 subs, PrimaLuna Evo 400 Tube Preamp, and either a turntable + phono preamp or an Esoteric SACD player in the mix. I must need at least an 8 guage dedicated line on a 30 amp breaker, or better yet two dedicated 10 guage lines, each on 20 amp breakers? How about one decicated 12 guage line on a 15 amp breaker. The total current draw on my system, playing as loud as you like, is less than 3 amps. There is no momentary draw that is going to starve my amps, which are solid down to 1 ohm, into clipping or failing to perform to thier max. While over building our power supplies may make us feel good, or even make us believe we are hearing better sound, what we know as confirmation bias, the accepted laws of electricity say it ain’t so. Your equipment only draws the current it needs. Having 5 times that amount hypothetically available doesn’t change a thing.
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A 30-amp breaker requires a 30-amp rated receptacle or you will be in violation of your local building/electrical codes. The fuse rating of the equipment is not a safe alternative because something else can be plugged into that outlet and it may not have a fuse to protect against an overload, creating a fire hazard.
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Yes. I was truly blown away at the difference in nearly every aspect of the sound.
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Z32kerber,
Congratulations on the upgrade! Best $450 I spent was for two 20A dedicated circuits, with audiophile quality receptacles…..the improvement was immediately noticeable and pronounced
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man, thats cool. i been thinkin of doing that for a good while. i wont have the time any soon, but hopefully ill get around to it next year.
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Thanks for the feedback. I’ll swap out the 30 amp breakers for 20 amp.
Smart move! 30 amp breakers require 30 amp plugs.
Mike
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The circuit breaker is there to protect the wiring in your home.
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@eric_squires Thanks for the valuable feedback. I should have known better. 20amp breakers are now installed.
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Thanks for the feedback. I’ll swap out the 30 amp breakers for 20 amp.
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@lak
+1 erik_squires
Thats what I was thinking also, the 30A breaker won't kick off and that could possibly damage something and/or be a fire hazard.
I honestly do not see any meaningful advantage with utilizing a 30 amp breaker. I can understand that psychologically (More is always better mindset) it being seen as beneficial. In terms of actual sound quality performance I can see no superiority over a 20 amp alternative.
Charles
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I used 30 amp breakers because a few people said they give more headroom.
...another audiophile myth.
Most audiophiles don’t realize that standard (non AFCI or GFCI) circuit breakers are mainly there for short circuits, and won’t trip on in-rush current (or momentary speaker amp demands of high current). 15 amp breakers will easily intermittently pass peaks of 30 and 40 amps (and more if needed), because that’s what a typical refrigerator or air conditioner pulls when it starts up (it’s called in-rush current). A 20 amp breaker with 10 or 12 AWG wiring (14 AWG with a 15 amp breaker will be fine too), with a decent wall outlet, is all that’s needed. An isolated or dedicated ground is an added plus.
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Zero benefit, significant risk and liability and not everything is a "dead short." Even if it is, in the time to trip the breaker anything not rated for the breaker's current is a risk.
But sure man, ignore best electrical practices for a non existent audio benefit.
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+1
Congratulations. Yeah, amazing isn’t. The stark difference doesn’t allow room for much interpretation.
I’m not sure you would classify this a significant risk. Audio equipment are fused and a dead short is a dead short and would trigger a 20a or 30a breaker. I will admit not to be a professional electrician. I assume a certified electrician did this… and would not have if it did not meet code. ?
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+1 erik_squires
Thats what I was thinking also, the 30A breaker won't kick off and that could possibly damage something and/or be a fire hazard.
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There's no audible benefit to a 30A breaker, and significant downstream risks. A downstream short in an AC cable, or outlets not rated for 30 A is a problem I wouldn't want to risk in my home.
The PS Audio PowerPorts are not rated for 30 Amps, only 20. If that's what you used you should downgrade your breakers to 20A.
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