I just bought a used Audio Research power amp without knowing it needs 20A connection. When I received the amp, there was no power cable included, and I've found out that the amp has a connection that I've never seen before. I thought it might be for 250 Volt, but later found out that this amp needs a special power cable with C19 type female connector and it has to be 12 AWG and 20A. So, I ordered a 20A 12AWG power cable and a PS Audio power receptacle that supports 20A male connector type. After reading a few more articles on 20A power amp, I may also need a 20A circuit breaker. The problem is, the circuit breaker for the audio room is 15A. Does it mean that I need a new breaker with 20A to use the amp? What a hassle. The seller did not mention anything about the cable power requirement and I assumed that it was included, but the seller didn't seem to have known anything about this amp. So, installing a new circuit breaker is something non tech people can do? If not, how much would I need to spend for professional job? Would it be just OK to use 15A circuit breaker for the amp as long as I use 20A 12AWG power code and don't turn the volume much high? Thx advance for your input.
No ARC amp (unless you have a pair of Ref 750 Monos perhaps) needs a 20A breaker and circuit.
ARC specify the 20A IEC because they believe its physical and acoustic properties are superior. Also they do not use the 20A male connector because most domestic circuits don’t accept it -- most (frankly all the ones I’ve ever seen) "20A IEC" cords come with a standard NEMA 5-15P
Use an appropriately rated cord and a 15A->20A IEC female adaptor if needed (such as the great models from Venom) and you will be fine. Or have your preferred cord reterminated -- AQ for example will do this for any of their cords at a modest cost
@ihcho I had to deal with a similar issue though my amp did come with a very good stock 20A cord.
However, the stock power cable (which I reiterate was quite good and capable) was surpassed by my aftermarket power cord, a 15A standard cable, with a 20A > 15A IEC adaptor.
I purchased another one of my aftermarket power cables with a 20A IEC termination and a 15A male three prong end. This surpassed the adaptor (same power cable, but new). [Emphasis - new without adaptor beat fully broken in with adaptor].
I encourage you to try both approaches, but I believe re-terminating will offer superior results.
You can use your already installed 15 amp breaker... no problem.And NO you cannot just stick in a 20 amp breaker to replace the 15 amp breaker in the box! The wires in the wall must be a certain size to use a 20 amp breaker. As others mentioned the IEC is just for more area to allow good transfer of AC power. For the state of the art stuff, yeah you would want several 20 amp lines. For mere mortals, a 15 amp will suffice until you decide to upgrade some more..
Folkfreak nailed it. Look at it in simple terms. If the amp drew more than 15 amps, it would trip the 15A circuit breaker in your electrical panel and further, ARC would likely mandate a 20A male plug and warn you to install a 20A line, 20A rated receptacle, and 20A breaker along with 10Ga Romex on a dedicated 20A line. Relax and enjoy your new amp. ARC has been designing their amps this way for quite some time now. It's admittedly kind of silly. I own a Ref 150 SE and love it.
So, I can just use an adapter, and everything is solved? All the C19 female type power cord I found in Amazon seem to have either 15A male type plug with 14AWG, or 20A male type plug with 12 AWG. The cable has to be 12 AWG (or higher, like 10 AWG), so I thought the only solution would be to use 20A plug cable, which means I need to have 20A power receptacle, which might require 20A circuit breaker. It is a big relief that there are much simpler solutions. I ordered a 20A/10AWG power cable with C19 female connector and 15A male connector. It will take a while to get it, but in the mean time, I can use an adapter with my existing 12AWG 15A power cable.
fsonicsmith, If my 15A circuit breaker keeps breaking, then I would think about installing a dedicated 20A breaker for the amp. Until it happens, I would be careful about not cranking the amp’s volume so high.
It is not ideal, but you can use the amp with a 15 amp line via a plug adapter. As long as you don't crank it up, you should have no problems. If the breaker trips, then you'll probably have to get your lines upgraded, which isn't a big deal- In fact, it might just be a significant upgrade for your system. Bob
I can't tell from the OP original post if the amp is standard 120 volt or 240 volt. If it's 120 then an adapter would work or better yet contact ARC give them the serial number and they could either sell you the right cord or advise on a proper after market cord.
It would help if you gave us the Model number of the ARC amp.
As for tripping the 15 amp branch circuit breaker. If the breaker trips it won’t be while listening to music even at a high volume level, jmho. If it trips it will be when the amp is first turned on. Can the breaker handle the inrush current needed to charge the caps in the power supply. Just a guess ARC designed a soft start circuit to limit inrush current.
Other factors to consider is what other loads are connected to the 15 amp branch circuit? Also the electrical panel/breaker manufacturer and the age of the breaker.
As for how the amp will sound connected to the 15 amp branch circuit? The wire gauge is more than likely #14awg copper. How many outlets are connected to the branch circuit? What other loads are connected to the branch circuit? Any lighting loads? CFL or LED? Dimmers? What is the wiring method used for the wire connections inside the wall outlet boxes? Pigtailed and then connected to the outlets, or, the outlet terminals were used, daisy-chained, to make the in and out connections of the Hot and neutral conductors? What is the distance, length, of the branch circuit wiring from the electrical panel to the wall outlet the amp will plug into? A little hard to figure that one. Add fudge for up, down, and around. Last but not least the age and condition of the wall receptacle outlet. Poor contact plug retention pressure will greatly degrade the sound of the amp.
Good chance you may want to hire an electrician to install a new 20 amp dedicated branch circuit for the amp. I would recommend #10awg wire. #12awg is bare minimum per NEC for a 20 amp circuit. Jim
You need a 20 amp line run to the amp. It probably should be a dedicated circuit , that is just for the amp. The C19 power cable is the standard for 20 amp equipment. Put all your other equipment on the existing 15 amp circuit.
I purchased an ARC 150M two channel. The amp has 10A fuse, so I guess it is fine with 15A receptacle. I bought an adapter, not a cable, and use the adapter with my 12 AWG power cable. I ordered 10 AWG power cable with 15A male and 20A female, and I will get it in two weeks. I also changed the receptacle with a PS audio power port classic receptacle. I am listening at a low ~ medium volume level, fearing trip the circuit breaker. I feel it sounds at least as good as my Plinius 102A. Maybe a little bit more clear and bright sound. Thanks for all the comments and help. I just feel so dumb to purchase this amp without even knowing the different type of power connector for 20A. ;-)
I am listening at a low ~ medium volume level, fearing trip the circuit breaker.
You can crank the volume up as much as want. The 10 amp Line fuse is a lesser value than the 15 amp breaker. The actual FLA on the amp is more than likely 8 amps or less. (8 x 125% = 10). Keep in mind that is continuous amps. Pushing the amp full bore. The 15 amp breaker will handle a continuous load of 15 amps all day long. It will pass short spurts of current well above 15 amps all day long. (Of course you have to take into account any other loads that are connected to the same branch circuit).
Your problem with the 15 amp convenience outlet branch circuit could be/will be VD (Voltage Drop) if you push the amp to hard. Basically starving the power supply of the amp. The caps in the power supply will have problems recharging.
Subject line is in regards to a power cord but the same would hold true (probably more so) for a 15 amp convenience outlet branch circuit for the amp you have.
Ralph - Manufacturer, Atma-Sphere Music Systems
There are two aspects, AC voltage drop and high frequency current limiting.
AC voltage drop is the voltage dropped from the wall to the input of the equipment in use. I’ve measured a loss of 40 watts on an amp that makes 140 watts, so no-one should be surprised that that might be audible as well. I used a 3 1/2 digit DVM to measure the voltage drop and it showed around 3 volts. This was a pretty standard but inexpensive Belden cord. A more expensive Belden cord with heavier gauge showed a lessor drop and more power out of the amp. So no mystery here.
The second issue is the high frequency current limiting. This is a bit trickier to understand, but its not quite rocket science. Almost any power supply consists of a power transformer, rectifiers and filter capacitors. When the the transformer voltage is higher than the capacitor voltage, the rectifier commutates (a fancy word for turns on and conducts). At that point the filter capacitors can charge up and will do so until the power transformer voltage falls low enough that the rectifiers cut off.
At that point the circuit using the power supply drains the filter caps. Since this happens 60 times a second, the drain is usually not very much at all, so its only at the very peaks of the AC waveform that the caps are be replenished. There might be only a few microseconds or milliseconds that this can happen, and quite a bit of current might have to flow during that time, essentially a high frequency event.
If the power cord limits current during this period, the performance of the circuit using the power supply might suffer, possibly due to increased IMD since the DC might have a bit more of a sawtooth on it than if the current was not limited.
I contacted ARC service and asked a question about this amp over two weeks ago, but no response yet. Most of time, it is more responsive and sometimes more detailed response I get from online forum than the manufacture's customer service. So far so good at moderate volume (9 o'clock position).
Either ARC had a lawyer write it, or ARC just stopped some guy off the street to write it.
Quote from page 2.
The AC power source for the amplifier should be capable of supplying 15 ampere for 100 or 120 volt units,
Yeah, really? 15 amperes..... I wonder how many layman read that as a 15 convenience outlet circuit meets that statement? I can tell you how the majority of electricians would read it. The equipment manufacturer says his piece of equipment needs a 120Vac 20 amp circuit.
Here’s the thing though. Technically ARC meets UL, and NEMA safety standards. It is also in compliance with NEC electrical code. The continuous (repeat continuous) FLA of the amplifier is not greater than 12 amperes. That complies with NEC, UL, and NEMA, electrical safety standards for a 15 circuit.
And then in the next paragraph it says;
For the very best performance on domestic 100 or 120 volt circuits the 150M should be connected to its own AC power circuit branch protected by a 20 amp breaker.
its own AC power circuit branch protected by a 20 amp breaker.
Normally it would be worded, 20 amp branch circuit. Per NEC the overcurrent protection device, breaker in this case, determines the size of the branch circuit. For a 20 amp branch circuit the bare minimum branch circuit conductor, wire, size is number 12awg. You can go with a bigger size, but not smaller than #12awg.
So why all the dancing around the branch circuit size ARC recommends for the amplifier? The vast majority of homes in the US convenience outlet circuits are 15 amp. (15 amp breaker, #14awg wiring). Living rooms, bed rooms, dens. Jim
As I said before, doing it the 'right' way would be the safest course, and probably give you a better outcome overall, but, I think running it with an adapter is fine as long as you don't push it. Even if you do, the breaker should kick in, and then you'll know how far you can go. B
Jim, I’m curious to hear your thoughts on pig-tailed vs. daisy-chained wiring of outlets, if you have the time. Not necessarily per audio requirements, but in general. TIA
@builder3 If the joints and pigtail are made-up using an electrical spring wire connectors then pigtail is my choice over using the outlet to make the feed through connections. An electrical spring connector will expand and contract with the heating and cooling of the wire connection always keeping the connection tight.
Jim, that looks great. When I built my shop, I used the pig-tail method on every outlet in the place, workshop, garage, and upstairs office. My thinking was that if I had an issue with an outlet, I wanted it confined to the one device, rather than everything downstream of the failure. I had an electrician or two suggest that I had went to a lot of extra work for nothing. I was still good with my choice, but was curious what was behind your comments. Thanks.