15A vs. 20A power cord questions

Regarding the phono-pre, this is down the line. I currently only use an integrated and a turntable. Which duplex should the turntable be plugged in to?

Not knowing anything about a VPI TT motor I would not plug it into the same duplex receptacle as the amp. That’s just my opinion.

Will a burned-in/not burned-in receptacle make a difference for the turntable motor?

I doubt it. Again, just my opinion.

I don’t know why you couldn’t plug the TT motor into the non dedicated branch circuit receptacle you were using for your entire audio system before. Save the Furutech receptacle for future.

The only thing you might want to check, (and I don’t know if it would mater), is if the old wall receptacle branch circuit is fed from the same Line, leg, in the electrical panel as the new dedicated branch circuit.

You could check it with a volt meter.

Do I need to burn-in each of the 4 receptacles. For instance, just because i’m running a box fan in one receptacle, that is not burning-in the entire duplex, correct?

Yes, each receptacle of each duplex will need to be burned-in, that you want to be burned-in.

Check out the link below. Scroll down the page of the link to the metal current carrying contact guts in side the duplex receptacle.

http://www.vhaudio.com/furutech-gtx-d.pdf

It does not take 6-8 months as mentioned above "assuming" you connect constant current drain devices (amps, house fans, etc..) to them and leave them powered on 24x7.

LOL.... You might want to take the time and reread my posts. The 6 to 8 months time frame is if the OP turned on and listened to his system on average 2 hours a day and then the amp was turned off. Surely you are not recommending the OP leave his tube amp on 24/7. That would be just silly.

Burn-in hours are burn-in hours.

Whether 2 hours a day on average, 500 / 2 = 250 days / 30 avg days in a month = 8 months. OR 2 hours X 7 days = 14 hours a week. 500 hours burn-in time / 14 = 35.7 / 4.5 weeks in a month = 7.9 months. 8 months.

OR

A box fan load running 24 hours a day, 7 days a week. 7 X 24 = 168 hours.

500 / 168 = 2.98. 3 weeks, not 6 or 8 months.

asp307,

I would plug the amp into the other duplex receptacle, jmho. I would have both the phono preamp and amp plugged into the same duplex. Analog and analog go together just fine.

The CDP would be plugged in the other duplex receptacle. Problem with both the CDP and amp being plugged in the same duplex receptacle, there is a greater chance of digital hash/noise traveling back out on the CDP power cord and re-entering the power cord and power supply of the analog power amp. (Coupling the digital CDP power supply to the power amp's power supply.)

Granted both duplexes are fed from the same branch circuit but they are separated by what ever the lengths of the two spurs of NM-B cable from the junction box below the floor to each wall duplex receptacle outlet. Every little bit helps.

You may not hear any difference the way you have it now. After you get the four receptacles of the two duplexes burned-in you could then experiment having both the CDP and amp plugged into the same duplex receptacle and then separate them as I described above. Listen for any differences in sound.  

Where is the amp plugged into?

Not the same duplex receptacle as the CDP?

asp307,

Glad to hear everything went as planned with the new dedicated branch circuit wiring. I see you ended up going with a single dedicated circuit.

4 1/2 hours through burn-in, I love what I am hearing although there is a marine layer of sibilance and grittiness. The detail retrieval is enhanced as well as the noise floor, background and soundstage. The dynamics are the best I have heard.

I’ve read anywhere from 500-800 hours of burn-in.

Yeah, it could take 500 hours means it could take 6 to 8 months for the receptacle/s to burn-in. You have more patience than I do.

What I would suggest is to connect some other loads to the receptacle the amp is plugged into. You could unplug the added load when listening to the audio system, then plug it back in after the listening secession. You need to have a load connected to the receptacle 24/7 until you get the amplifier receptacle burned-in.

Types of loads? Something that uses/consumes more power than just a few watts.

Maybe a box fan. Something that draws at least an amp or two.

If the floor is carpeted and you have a portable vacuum cleaner use the receptacle the amp is plugged into when vacuuming. Most portable vacuum cleaner motor’s draw up to 12 amps. That is a great load to connect to the receptacle.

After the receptacle, for the power amp, is burned-in you have three more to go.

Good luck.

asp307,

The question should be what impact will a 20 amp dedicated branch circuit have on the sound you hear from your audio system.

IF your audio system is now being fed from a 15 amp convenience outlet branch circuit, that more than likely is wired using #14awg wire.

Factors to consider:

Age of the existing branch circuit wiring?

What other loads are connected to the branch circuit? It’s not unusual to see lighting loads connected to the convenience outlet branch circuit as well. Any dimmers on the lighting of the branch circuit?

At what point in the length of the branch circuit run is the wall receptacle connected to the branch circuit? What is the length of the #14 gauge wire from the wall duplex receptacle to the electrical panel?

What is the wiring method used for feeding in and out of each outlet box for connecting the wall duplex receptacles to the branch circuit wiring? Is the in and out hot and neutral conductors jointed, connected, together and then pigtailed out for the duplex receptacle connection to the branch circuit? Or was the receptacles used as the connection junction point for the in and out hot and neutral conductor wiring? Was the side terminal screws used to make the connections, or was quick stab in the back side of the device used? What is the conductivity condition of the connections? Any corrosion?

What differences should you hear with the new 20 amp dedicated branch circuit using 10-2 with ground NM-B cable?

Lower noise floor.

Tighter deeper controlled bass.

Cleaner highs.

Fuller mid range.

More air, open sounding.

Just an all around better sound presentation from the power amp.

NOTE: If you bought the Rhodium receptacles I hope you bought them pre-cooked, burned-in. If not you probably will not like the sound you will hear from your audio system. Don’t blame it on the new 20 amp dedicated branch circuit. It will be the fault of the Rhodium plating on the contacts of the new receptacle not being burned in.

IF you have 2 dedicated branch circuits installed, when the electrician is finished with the job and the two circuits breakers are turned on have the electrician show you at the two wall duplex receptacles branch circuits, (with his volt meter), they are fed from the same Line, leg, from the electrical panel.

asp307 said:
I have two wall receptacles for him to install. Should each one be on a different breaker? Do you run the 10-2AWG to each wall receptacle?

What were you trying to achieve by doing this? What have you achieved by doing this?

It’s up to you how many dedicated branch circuits you want to have installed for your audio equipment.

You can have just one installed and have the electrician install both duplex receptacles on the single dedicated branch circuit. If you go this route I recommend you have the electrician install a separate wall box for each duplex receptacle even though he will tell you it is cheaper to install both of them in a 2 gang box putting the duplexes side by side.

Problem with the duplex receptacles installed in a 2 gang box side by side is if you have any equipment or may have in the future that uses a wall wart. Most wall warts when plugged in covers part of the receptacle of the duplex receptacle next to it.

Something else to think about is the location of the wall receptacles.

Do you want them hidden out of sight? Problem with that they are a pain to unplug equipment from during a lightning storm, and even a bigger pain trying to plug them back in. Same problems if you want to experiment with different aftermarket power cords.

More than one dedicated branch circuit?

You said you all ready have 2 Furutech GTX-D 20A duplex receptacles.

Gold $234.99 each.

Rhodium $244.99 each.

And from what I have read about the amount of burn-in time required for the Rhodium receptacles a pre cooked duplex receptacle runs $264.99 each.

So the only additional cost for another dedicated branch circuit is the cost of the NM-B cable, the additional 20 amp circuit breaker, and a little more labor. As for the labor the only additional time involved is installing the NM-B cable, installing the 20 amp circuit breaker, and terminating the hot, neutral, and equipment ground, at the electrical panel.

Sounds like a no brainer to me. Install two dedicated circuits. One for each duplex receptacle. Someday you might add some digital equipment to your audio system.

Who says an old dog can't learn new tricks.

Thank you for enlightening me. No isolated ground rod.

I installed two dedicated circuits using #10-2 with ground MN-B cable.

One for digital and the other for analog.

It’s you call if you want to spend the extra money for the other line.

Because you are using #10 branch circuit wiring you should not have any fluctuating VD, voltage drop, problems playing moderate to loud dynamic music through your amp. And because all your equipment is analog one dedicated circuit is probably all you will ever need.

If you think there is a chance some time down the road you may add some digital equipment to the mix you could have the electrician install another cable now for future to a separate cut in wall box. Just have him put a blank cover plate on it for now. At the electrical panel he could terminate the neutral and equipment ground wires and tape off the end of the black hot wire for the future if you decided to use it. Extra price? Material plus just a little more labor cost. Definitely cheaper now than later. Future hook up cost? One hour labor rate, should cover it.

asp307 said:
"I’m installing dedicated 20A lines with 10AWG cable"

Lines? More than one.

Not knowing what the wiring layout method will be for the NM-B cable installation, if possible after the electrician gets out of the electrical panel and starts the horizontal parallel runs of the cables ask him if possible to keep them separated from one another by at least 12". If they are installed right next to one another for several feet when a connected load is connected to the cables the current carrying hot and neutral conductors magnetic fields will induced AC voltage/noise onto one another. (Same reason why dedicated branch circuits should never be installed in a conduit or raceway with other branch circuit wiring.)

Have him keep the dedicated branch circuit NM-B cables away from any other branch circuits that may have light dimmers connected to them. The load side wiring as well as the line side feeding the dimmer, (when turned on light/s dimmed), emits Harmonics RFI as far as 3’ to 5’ in all directions from the wiring. (The wiring becomes an antenna). If your new dedicated circuits are closer than 3’ the wires will pick up the RFI from the dimmer emitting wiring.
https://www.youtube.com/watch?v=OCK5W9vlAE0

When he connects the branch circuits to the branch circuit breakers in the electrical panel make sure they are all fed from the same Line,leg. All from Line 1 or all from Line 2. Not from both.

Have him verify they are all connected to the same by using his volt meter and measure for voltage from the Hot contact of one duplex receptacle dedicated branch circuit to the Hot contact of all other dedicated circuits duplex receptacles.

If they are all fed from the same Line, leg, he will measure zero volts. If he measures 240Vac nominal between any of then they are fed from both Lines.

For audio equipment connected together by wire ICs you want all the equipment fed from the same Line, leg.

asp307 said:
It was recommended to me by a US producer of speakers/cables to ground to the earth using rods and to use a twisted pair for the connection between the breaker and the outlet.

Send him a copy of this.

Quote from Link below:

>>

"Grounding Myths

From Henry W. Ott’s big new book "Electromagnetic Compatibility Engineering"

3.1.7 Grounding Myths

More myths exist relating to the field of grounding than any other area of electrical engineering. The more common of these are as follows:

1. The earth is a low-impedance path for ground current. False, the impedance of the earth is orders of magnitude greater than the impedance of a copper conductor.

2. The earth is an equipotential. False, this is clearly not true by the result of (1 above).

3. The impedance of a conductor is determined by its resistance. False, what happened to the concept of inductive reactance?

4. To operate with low noise, a circuit or system must be connected to an earth ground. False, because airplanes, satellites, cars and battery powered laptop computers all operate fine without a ground connection. As a mater of fact, an earth ground is more likely to be the cause of noise problem. More electronic system noise problems are resolved by removing (or isolating) a circuit from earth ground that by connecting it to earth ground.

5. To reduce noise, an electronic system should be connected to a separate “quiet ground” by using a separate, isolated ground rod. False, in addition to being untrue, this approach is dangerous and violates the requirements of the NEC (electrical code/rules).

6. An earth ground is unidirectional, with current only flowing into the ground. False, because current must flow in loops, any current that flows into the ground must also flow out of the ground somewhere else.

7. An isolated AC power receptacle is not grounded. False, the term “isolated” refers only to the method by which a receptacle is grounded, not if it is grounded.

8. A system designer can name ground conductors by the type of the current that they should carry (i.e., signal, power, lightning, digital, analog, quiet, noisy, etc.), and the electrons will comply and only flow in the appropriately designated conductors. Obviously false."

Henry W. Ott

/////

Posted by Speedskater:
Dedicated Power Line Recommendations - REPRISE! »

>>>>>

asp307 said:
Regarding a twisted pair or standard cable to link the breaker to the outlet, any advantages or is it all about the grounding?

About how long will the branch circuit run be? Don’t forget to figure up, down, and around, when figuring the total length of the run. (2 conductor with ground only! Hot, Neutral, and ground)

The wiring and wiring method used depends on the state and or local electrical code of Pittsburgh, PA. The electrician you hire will know what is code for your town. He will determine what will work for your wiring installation job.

IF NM-B sheathed cable, (Romex is a trade name of), can be used for the electrical wiring installation that works great for audio dedicated branch circuits.

IF because of code or because other reasons it has to be in conduit ask the electrician if MC aluminum armor cable meets code for your town. (2 wire with ground only! Hot, Neutral, and insulated green wire.)

If that meets code make sure he buys solid wire conductors and not stranded wire. Don’t let him talk you out of it. Especially if you want to use #10awg wire. Trust me he will try to get you to use strand wire. If he says nobody has 10-2 with ground solid wire MC AL armor cable tell him to try an electrical wholesale house in town. They will have it.

Worse wiring method for audio branch circuits is for the dedicated branch circuit wires pulled in an empty conduit where they are loose and randomly laying inside the conduit. This method can lead to induced voltage noise on the equipment grounding conductor.

A true dedicated branch circuit does not share a conduit or cable with any other branch circuits.

Example: 10-2 with ground NM-B sheathed cable.
http://www.wireandcabletogo.com/10-2-W-G-NM-B-Wire-Orange-250ft-500ft-or-1000ft-Coil.html?gclid=CP3y...

Example: MC AL armor cable
http://www.southwire.com/products/ARMORLITETypeMCOEM.htm

"As for the use of an isolated earth ground rod, that’s a no, no.

The purpose of the safety equipment ground is to provide a low resistive path for ground fault current to return to the source. Mother earth is not a low resistive path. If the earth is used as a path for ground fault current, and there is a ground fault event, the area around the earth driven ground rod works great for hunting fish worms.

The earth does not possess some magical mystical power that sucks nasties from an audio system".

THIS! It's REAL important! ALL grounds must return to the ground buss in the service panel.

asp307 said:
Regarding a twisted pair or standard cable to link the breaker to the outlet, any advantages or is it all about the grounding?

ASp307,

It would help if you said what country you live in. I assume it is a country that has 120V power. The reason I say that is because of the type of receptacle you said you were using in your OP.

Here is some reading material for you. Read pages 15 through 36.

http://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf

Jim

Hi gs5556,

Glad to see you posting again.

Most manufactures of audio equipment want and need to use a 15 amp plug to feed their equipment. As you know the majority of the convenience outlet branch circuits in homes are 15 amp, using #14awg copper wire. Only a 15 amp receptacle can be installed, connected, to a 15 amp branch circuit.

Audio Manufactures wouldn’t sell much equipment if they used a 20 amp male plug. So they need the 15 amp plug if they are going to sell audio equipment to home consumers in the US and Canada.

I think the problem with some manufactures, that build big amps, isn’t that their equipment draws more than 12 continuous amps. That’s a lot of amps for an amplifier in a home. 12 amps X 120Vac = 1440 VA, watts.

The problem is some manufactures are too tight to install a soft start circuit for powering up the amp. Without a soft start circuit the full inrush current trips the 15 amp branch circuit breaker at the electrical panel. And the bad thing, the manufacture probably knows it’s going to happen.

Sometimes in the owner manual it might say the amp should be fed from a 20 amp dedicated circuit. And that is the manufacture’s way out. In some cases even a standard 20 amp breaker will trip due to inrush current.

Jim

I am an easily confused old man.

My Atma-Sphere MA-1 140 watt tube amps use 5 amp fuses.

When I look at these fuses, the wire connecting one end to the other is absolutely tiny. At my age I need reading glasses to see it. Yes it is that thin.

This is the conduit through which the electricity flows. All the electricity.

The question I have: do you have an isolated ground with this dedicated 20amp service?.

This involves running a new wire outside, connected to a new copper rod, and having that rod driven into the ground, deep.

LOL, there is a lot more to many aftermarket power cords than merely the size of the conductors used. Nothing posted thus far has addressed any of that.

>>>>>>>>>>>>

Here is a quote from a post from Ralph, of Atma-Sphere:

"With power cords its all about voltage drop across the cord. Some of that is at 60Hz, and some of that is much much higher- well above 30KHz-100KHz depending on the power supply in the unit with which it is being used.

I’ve seen a 2 1/2 volt drop rob an amplifier of about 30% of its output power. The cord was rated for 10 amps, and the draw was about 6 amps. This measurement was done with a simple 3 1/2 digit Digital Voltmeter.

The more insidious problem is high frequency bandwidth. The power supplies of most amplifiers have a power transformer, a set of rectifiers, and a set of filter capacitors. The rectifiers only conduct when the power transformer output is higher than that of the filter caps. So:

When the caps are fully charged the amp is able to play. As it does so, the caps are discharged until the AC line voltage waveform gets high enough again that the rectifiers in the power supply are able to conduct. Depending on the state of charge of the filter capacitors, this might only be for a few microseconds or it might be a few milliseconds. Either way, the charge is a spike which has very steep sides- and requires some bandwidth to make it happen.

If the power cord has poor high frequency response, it will current limit on these spikes. This can result is subtle modulations in the power supply or even a sagging power supply voltage.

Romex wiring found in many buildings actually works quite well. So it really becomes all about that last few feet and also how well the power cord is terminated- molded cords generally are not terminated very well. If the ends of your power cord get warm after a while, you know you have a problem!

This can be measured, its quantifiable and also audible as many audiophiles know. Anyone who tells you differently probably has not bothered to do any measurements- please refer them to this post.

I can go into more depth but this is it in a nutshell. Incidentally, Shunyata Research is refining an instrument that does a more in-depth analysis of what this is all about. At the link you will see that their tests essentially confirm what I have said here."
http://www.theaudiobeat.com/visits/shunyata_visit_interview.htm

End of quoted material.

>>>>>>>>>>>>>>>>>>>>>>>>>>>

Agon thread Link:
https://forum.audiogon.com/discussions/audiphile-power-cords#41

<<<<<<<<<<<<<<<<<

As for the use of an isolated earth ground rod, that’s a no, no.

The purpose of the safety equipment ground is to provide a low resistive path for ground fault current to return to the source. Mother earth is not a low resistive path. If the earth is used as a path for ground fault current, and there is a ground fault event, the area around the earth driven ground rod works great for hunting fish worms.

The earth does not possess some magical mystical power that sucks nasties from an audio system.

I am an easily confused old man.

My Atma-Sphere MA-1 140 watt tube amps use 5 amp fuses.

When I look at these fuses, the wire connecting one end to the other is absolutely tiny. At my age I need reading glasses to see it. Yes it is that thin.

This is the conduit through which the electricity flows. All the electricity.

The question I have: do you have an isolated ground with this dedicated 20amp service?.

This involves running a new wire outside, connected to a new copper rod, and having that rod driven into the ground, deep.

A 20-amp power cord must have 20-amp rated connectors on both sides along with #12 or larger conductors.

I would agree, for a 20 power cord.

If you have a cord that has #12 or larger conductors (or multiple conductors totaling over 12awg in area) but 15-amp connectors on either or both sides, it is still a 15-amp cord. Manufacturers usually call that a "high current" or "amplifier" cord but they cannot call it a 20-amp cord.

Again, I would agree with your above statement.

If your equipment -- like most equipment -- has a 15-amp connector (C-14 receptacle) then you cannot use a listed 20-amp cord because it will not fit.

And again I agree.

But what if the manufacture of a CDP installed a 20 amp IEC male connector on the back because he believes the 20 amp IEC connectors connection is better than a 15 amp IEC connectors and the FLA on the piece of equipment is, say, 2 amps.

If he supplies the power cord for the amp The IEC female connector will naturally be 20 amp and I can guarantee the male plug will be a NEMA 5-15P (15 amp) plug. The conductors of the cord who knows. Could be #14, it could be #16 gauge.

Because it has a 15 amp male plug, and the conductors are 16 gauge can you truly call that a 15 amp power cord?

See that’s the problem with IEC connectors. There isn’t any real standardization. They are not idiot proof.

What happens if the user someday finds it in his odds and ends box and uses it on a big Krell power amp, (he just bought used that didn’t come with a power cord), that has a 20 amp IEC connector on the back of it. Must be ok to use. It plugged in the back of the amp and the plug plugged into the wall 15 amp duplex receptacle. If the cord is 6ft long and the wire is 16 gauge because of the VD + heat that will be generated by the connected load to the hot and neutral conductors add that to a possibly long length of the in wall #14awg branch circuit wiring there is a chance the current passing through the 15 amp circuit breaker may be less than 15 amps. In that case the breaker could very well not trip open.

The power cord will not affect the power consumption or current draw of the amplifier. Your amplifier’s fuse will limit the current well below the 80% listed amp threshold for the power cord.

Well not in the sense power consumption meaning it can deliver more power than the branch circuit can deliver but it is possible depending on the wire size used in the cord and the connected load VD, voltage drop, could be a factor, there in limiting power to an amplifier. Even if the fuse is a slow blow 8 amp fuse it will easily pass short spurts of current draw well exceeding the fuse’s 8 amp rating if the power amp is being driven hard playing high dynamic music.

Best regards,

Jim

jea48 said:
" A manufacture can build, and does, a power cord that has an IEC 20 amp female connector on one end and a 5-15P plug on the other end. "

cleeds
Quite so. And, if the device itself draws 15A of current or less, that’s perfectly safe.

No, the equipment shall not draw more than 12 amps FLA continuous load per NEMA, NEC, and UL for a cord and plug where the manufacture wants to use a NEMA 5-15 (15 amp) male plug.

16 amps max for a 20 amp cord and plug if the equipment manufacture wants to use a NEMA 5-20P male plug.

Works great when the equipment comes with a captive held attached power cord.

How about the guy that goes out and buys a big honken Krell amp that has a 20 amp male IEC connector on the back of the unit, a power cord made of #10 wire, conductors, with a 20 amp IEC connector and a NEMA 5-15 (15 amp) male plug on the other end. The user plugs the NEMA 5-15P plug in convenience outlet 15 amp duplex receptacle in the living room, no problem at all. Perfect fit.

The user turns on the amp and trips the breaker in the electrical panel. The user calls the dealer and says, hey there is something wrong with the amp. Every time I try to turn on the amp it trips the breaker at the panel. I tried it at least a half a dozen times. Dealer response: The breaker is probably a 15 amp, just change it out to 20 amp breaker.

Next time you go to a hardware store or Home Depot see if you can find an extension cord with a 5-20R (20 amp) female cord cap on one end and a 5-15P (15 amp) plug on the other end. You won’t find one......

As for the current handling ability of a NEMA 5-15P 15 amp plug vs. a NEMA 5-20P 20 amp plug there isn’t any. If you look at the size of the hot and neutral blades they look exactly the same. Same length, same width, same thickness.

What is different between the 5-15P and the 5-20P plug is the orientation of the neutral blade. The neutral blade is turned 90 degrees of that of the Hot blade for the 5-20P, (20 amp), plug.

A 5-20P plug will not plug into a 15 amp receptacle. A 20 amp receptacle can only be installed, connected, to a 20 amp branch circuit. ( A 20 amp receptacle can not be installed, connected, to a 15 amp branch circuit.

A 15 duplex receptacle can be connected to a 20 amp branch circuit though.

And here is the stupid thing imo. A manufacture can build, and does, a power cord that has an IEC 20 amp female connector on one end and a 5-15P plug on the other end. And what’s worse yet, be UL listed.

Note: All per NEC code.

Are there any issues with running 15A power cords into a 20A outlet and line?

No, not any problem at all.

 I am currently using the standard IEC power cords that came with my Rogue Cronus Magnum and VPI Scout 1.1.

After about a month or two listening to the new dedicated branch circuits you could always try an after market PC on Rouge amp.

I would stay with the 15 amp male plug. No need for a 20 amp male plug.

As for the wire size used in a cord with a 15 male plug it can be as small as 16 awg or as big as what ever will fit the male plug and or the IEC female connector.

For the amp I would use a PC with at least 12 gauge wire, conductors. If it was me I with go with 10 gauge wire, conductors.

Before you buy anything I would check and find what other guys are using on Rouge amp. Don't just go out and buy something to see how it sounds.

Just an example, I have an ARC tube amp and it hates shielded cables. A shielded cable sucks the life out of the sound of the amp.