110 (or 120) vs 220


Hi,

IF an amp can operate at both 110 and 220, and a dedicated circuit is being installed for that amp, is there an advantage to a 220 v circuit? Or is the answer "it depends on the amp"? Or is the answer simply "no"?
Convert?fit=crop&h=128&rotate=exif&w=128jimspov
basically ,the 220 will flow on more wires creating less restriction . 220 is more efficient ..basically :)
Power, (Watts, VA)  =  Volts X Amps.
@220 flows on the same number of wires 120v uses one hot and one neutral. 220v uses 2 hot and no neutral. You might be thinking of 3 phase
120 and 220 is single phase
Alan
Possibly. At 240 volts half the current is drawn through the wiring and that can result in less power line noise in and out of the amplifier. We pay a lot of money in power cords to do just that. Speaking of which, you can’t use the standard 5-15 (up-up) blade power cord for 240 volts, so a disadvantage may be the cost of a special order audiophile power cord with a 240 volt plug.

jimspov,

Not sure what country you live in, your profile says n/a.

If you live in the US it is against NEC code to install a 240V dedicated circuit to power a consumer sold piece of audio equipment. Good chance your local electrical inspection department adopted that section of NEC code as well. If that is the case Your home owner insurance follows that as well when it comes to covering a claim.

As gs5556 said in his post you would have to use a plug designed and rated for 240V as well as a matching wall receptacle. That would pretty much eliminate the use any aftermarket power cords and or audio grade receptacles.

Next problem is the equipment was designed to be fed by an AC power system that has a Hot Line conductor and a Grounded Neutral Line conductor, be it 120V (North America), 220V, 230V or 240V as found in Europe for example. The 240V mains voltage in the US consists of 2 Hot ungrounded conductors. The audio equipment is designed to be connected to a branch with a hot and neutral conductor. Only the Hot conductor has a Line safety fuse that is there to protect the piece audio equipment from an over load or short circuit condition. If the safety equipment grounding conductor, from the wall receptacle/branch circuit is used on the piece of audio equipment, then the fuse will blow in the case of a hot to chassis ground fault condition. (No live parts inside the equipment past the blown fuse.)

The neutral conductor feeds the other lead of the power transformer of the piece of audio equipment.

So what if you feed the piece of equipment with 240V, where both lines are Hot ungrounded conductors? If there is an overload the safety fuse will blow breaking the overload condition. Of course the other Hot line of the 240V will still be hot inside the equipment. Through the primary winding of the power transformer >>> to the on/off power switch of the piece of equipment, and if the switch is on, closed, >>> to the load side of the blown fuse. Problem? Probably not if the overload was caused by something on the secondary side of the power transformer.

What if the primary winding of power transformer shorted out? The fuse should blow. But what about the other Hot unfused conductor that is connected to the other lead of the primary winding of the transformer? What if the short bared the insulation from the winding and it comes into contact with the iron core of the transformer? Do you see a problem? I can see several.

What if the piece of audio equipment uses the wall receptacle/branch circuit safety equipment ground and a ground fault condition happens on the hot line that is fused that feeds one the leads of the power transformer. Will the fuse blow? Yes, it should... But what about the hot conductor that is connected to the other lead of the primary winding of the power transformer? If the ground fault survived the other Hot line to chassis when the fuse blew then a closed 120V circuit may exist. Hot ungrounded conductor connected to the primary winding lead >>> through the primary winding of the power transformer >>> through the wiring of the equipment to the ground fault condition connection to the chassis >>> out on the safety equipment ground wire of the power cord >>> to the equipment ground of the wall receptacle >>> through the equipment grounding conductor of the branch circuit >>> to the neutral grounded conductor in the main service electrical panel. Houston we have lift off. The piece of audio equipment is being fed by 120V.

I could give many more What IFs to consider.

Last but not least usually audio equipment involves separate pieces of equipment that are connected together by wire interconnects. Rule of thumb is to feed all the equipment, that is connected together by wire interconnects, is to feed them from the same Line, leg, from the electrical panel. How are you going to do that if some equipment is fed by 240V and some are fed by 120V?

Hi jea48,

That's a pretty thorough response - thanks. If it is against code I won't do it.

I presume that IF the unit was designed to run at 220-240 (as well as 110-120) that most of your concerns would be alleviated? Running other equipment off of the same circuit is theoretically possible with a voltage converter. But ya, I'd have to give up my new Zu mains cable. :(

Btw, thanks for pointing out that my country doesn't show up. I live in Canada and did enter that info, but for some reason it is not coming through on Audiogon. I've sent an e-mail to  support@easypost.com.


I presume that IF the unit was designed to run at 220-240 (as well as 110-120) that most of your concerns would be alleviated?

Only if one of the 2 Line conductors feeding the equipment was a neutral, a grounded conductor.

One Hot ungrounded conductor. The other Line a neutral grounded conductor that is at earth potential.

In the US or Canada this can be achieved cheaply by using an autotransformer.

It can step up 120 to 240 where the neutral is common. The 240V out maintains the 120V feed common neutral.

Example:

http://www.toddsystems.com/geninfo.html

https://www.canadatransformers.com/what-is-autotransformer/


You can also do it by using an isolation transformer.

One secondary winding lead, leg, of the 240V out is intentionally connected to ground making it the neutral, the grounded conductor. This method is a lot more involved. It is not for a layperson without any experience with isolation transformers.

For an amplifier to be designed to run on either 120 or 240 it must have two fuses, one for the hot and one for the neutral. When it is running on 120, the fuse on the neutral is just dead weight and does nothing but provide continuity. When it's running on 240, that "neutral" is now doing duty as a hot conductor and can pull short circuit current under a fault -- hence the reason for the second fuse. Don't forget to change out the fuses to a lower (usually half) amperage since the current draw is now half at 240 volts.

If there in only one fuse then do not run it at 240 regardless if there is a split primary with a switch or jumpers capable of conversion or else you will run the risk of what jea48 outlined above.

Also, you should not run other equipment off a 240 circuit. Theoretically, you can pull power off one leg and feed it to a 120 outlet and run a neutral  back to the panel but that is against code because it unbalances the circuit. The correct way is to leave it dedicated. That circuit will have a 2-pole circuit breaker feeding a 250 volt receptacle (6-15 or 6-20) which has the blades rotated at a 90 degree angle (horizontal) so that you cannot accidentally plug a 115 volt appliance into that outlet, resulting in a pretty fireworks display.

Your electrician knows how to wire everything up if you decide to go with 240.

A neutral ( The Grounded Conductor) should never be fused. If a breaker is used both poles must be mechanically connected together so both contacts will open simultaneously at the same time.


http://www.audioresearch.com/ContentsFiles/VT50_SchemPL.pdf

Scroll down the page to the drawing of the primary winding side of the transformer.

The primary has dual windings so it can be connected to 120V or 240V mains. (Parallel for 120V. Series for 240V)

Note only one fuse is used. The HOT conductor, be it, 120V or 240V connects to the Line side of the fuse.

The neutral conductor, (The Grounded Conductor), connects to the other Line lead of the of the configured primary winding of the transformer.

Ok. If the amp isn't designed to do both with no modifications from me then I don't want to do this. (I have a call in to the manufacturer).

I have a CPAP machine and it will automatically switch from 110 to 220 it I switch the power cord. Guess it isn't so simple for an amp!

For the interconnects, I was referring to a converter that you plug into the wall and then you plug the ancillary equipment into it. The converter takes 220 volts from the wall and converts to 110 for the equipment to use.

http://www.audioresearch.com/ContentsFiles/VT50_SchemPL.pdf

Scroll down the page to the drawing of the primary winding side of the transformer.

The primary has dual windings so it can be connected to 120V or 240V mains. (Parallel for 120V. Series for 240V. The change must be done internally inside of the piece of equipment.)

Note only one fuse is used. The HOT conductor, be it, 120V or 240V connects to the Line side of the fuse.

The neutral conductor, (The Grounded Conductor), connects to the other Line lead of the of the configured primary winding of the transformer.

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


Some audio equipment have a switch mounted on the back panel to switch from 120V to 240V Can’t get any easier than that.

BUT, BIG BUT.... The AC power that you connect to the equipment must have only one Hot ungrounded conductor and one Neutral conductor, (The Grounded Conductor). That is the AC power system the manufacture, of the equipment, designed it to be connected too. Not 2 Hot ungrounded conductors as your electrical service panel has.

My understanding is the mains power you have in Canada is the same as here in the US.

120/240Vac The Utility power transformer has three output legs, conductors, wires, that feed your home.

At the main service electrical panel you have 2 HOT ungrounded Lines, Legs. They are called Line 1 (L1), and Line 2 (L2). If you measure from L1 to L2 you will measure 240Vac nominal voltage.

The third wire that comes into the electrical panel is called the neutral conductor. This wire is common to both L1 and L2. If you measure from either L1 or L2 to the neutral conductor you will measure 120Vac nominal.

By NEC Code the service entrance neutral conductor must be intentionally connected to earth. This makes it the Grounded Conductor. (There is a lot more that has to be done than just saying it must be connected to earth. For simplicity lets just leave it at that).

>>>>


For you, I see no advantage of feeding 240Vac power to a dual rated 120/240V piece of audio equipment. Even if you use a transformer to create a neutral conductor to feed the 240Vac equipment. It will not sound any better and in fact it could sound worse if the transformer is not sized properly.


Feeding it directly from the main electrical panel with the 2 Hot, L1 and L2 Lines Is, I would guess, a safety code violation in Canada. I don’t know if it is or not though.

Might it sound better? Don’t know. It would be as some call it, fed from balanced power.

Would it be safe? No not in my opinion as well as gs5556, as explained above in previous posts.


My reason for doing this is that my tube amp is rated at 35 watts / channel. I'm buying new speakers after having my Paradigm 5se's for over two decades.

I naively thought if I doubled the voltage I could ~double my available power (~quadruple at 4 ohms?) and that would vastly increase the pool of speakers I could choose from (e.g., Totem, Magnapan).
Never ran across no 2 pole breakers feeding audio equip in NEC.
Only advantage would be 1/2 current so you could use small gauge wire.
Also Audio equipment doesn't draw that much current to warrant 220v
Post removed 

russe41,

Quote from 2014 NEC Code

210.6 Branch-circuit voltage Limitations. The nominal voltage of branch circuits shall not exceed the values permitted by 210.6 (A) through (E).

(A) Occupancies Limitation. In dwelling units, and guest rooms or suites of hotels, motels, and similar occupancies, the voltage shall not exceed 120 volts, nominal, between conductors that supply the terminals of the following:

(2) Cord-and-plug-connected loads 1440 volt-ampere, nominal, or less or less than 1/4hp.


jimspov said:

I naively thought if I doubled the voltage I could ~double my available power (~quadruple at 4 ohms?) and that would vastly increase the pool of speakers I could choose from (e.g., Totem, Magnapan).


Sorry, it doesn't work that way.

The best thing you can do for the amp is give it a 120V  20 amp dedicated branch circuit.