100v,115v versus 230v

glupson6,016 posts

08-10-2020
11:15am

jea48,

"Unless a piece of equipment, like a monster power amp, consumes more than 1440 volt-amperes continuous power it’s a violation of US electrical safety code to install a 240V branch circuit and receptacle in a US residential dwelling."

How does it go in real life? In the U.S.A., I have usual 110V outlets, but I do have a few 220V (240?), too. Granted, they are used for washer, air conditioning, etc., but I have a few unused ones, too. I have nothing to plug into them (except the tuntable that would then be too far so no need anyway), but I did not fully understand your post about "legality" of them even being there.

@ glupson

but I have a few unused ones, too. I have nothing to plug into them (except the tuntable that would then be too far so no need anyway),

Just a guess the "unused ones" were installed at the time for "220V" window air conditioners.

How does it go in real life? In the U.S.A., I have usual 110V outlets, but I do have a few 220V (240?), too.

There is a good chance if you measured the voltage at your 110V outlets it is closer to 120V than 110V. What ever it measures the hot Line 1 to hot Line 2 voltage at the electrical panel will/should measure twice that.
Example: Hot Line to neutral, 110V. Hot Line 1 to hot Line 2 will measure 220V.


Audio equipment that has dual voltage primary windings power transformer will still output the same secondary winding(s) voltage and exactly the same volt-ampere rating(s). The only thing that could influence the performance of say a power amp would be Voltage drop on the mains if a 120V branch circuit is used verses a 240V branch circuit.

Possibly another reason, for here in the US, if 240V mains power is used it basically could be considered balanced power, 120V - 0V - 120V.



As for this:

stefano_f1 posts

08-11-2020
10:50am

I note that in addition to the voltage also the frequency changes,
230-240 V 50 Hz and 110-120 V 60 Hz.
In my humble opinion, the effect of the different frequency must also be considered,
or at least postulated that this difference is considered negligible.
In a rigorous scientific study it should be proven, not in this case

A transformer designed to work optimally at 50Hz also works at 60 and vice versa, of course, but since these are non-macroscopic listening differences,
a 20% frequency difference may not be so negligible.
Thanks in advance to whoever answers me .

@ stefano_f


The frequency has nothing to do with whether the voltage is 230-240V or 110-120V. The frequency is determined by the Utility Power Company’s generating plant.
https://www.worldstandards.eu/electricity/plug-voltage-by-country/

Jim.

@ SABIH I do not use a ( step up /down transformer. ) My amps are voltage sensing. What ever voltage they see that is what they run on....Min/100V.Max/250V....

Millercarbon was correct.

Also, the feed from the pole top transformer to a home in the USA is 240 Volts.  You actually get two 120 volt feeds at different phase angles.  Three phase systems A,B,C phases are what is generated and transmitted. This is world wide.  The higher the transmission line voltage the less power losses and consequently the less costs in power generation/transmission/delivery.

Every home in America has 240 volts at the service panel.  One can run 240 volt to outlets if desired.  The power utility does not have to do anything.  This is all from within the home.

Clear?  USA had invested early into 120 Volts and it is/was too expensive at such a late date to change the appliance/light/equipment standard to 240 Volts.  but, remember, there is 240 Volts available in all homes in the USA.  

Now, audio equipment takes whatever input operating voltage and converters it to DC voltage via the internal power supply.  That typically includes transformers taking the 240 Volts or 120 Volts input and converting it to whatever lower/higher AC voltage is needed before converting to DC Volts within the power supply.  Rectify the AC Volts and Viola, you have DC.  Add some filtering and regulation and there is your power supply.

my point, is that as long as the input voltage is adequate and the power supply is correct, there should be absolutely no difference in sound quality.  I say should be.  There will be differences if the lower input voltage and power isn't up to snuff.

Power = V x I = (V x V)/R = (I x I x R).  The power input is exactly the same whether you are using 120 Volts or 240 Volts.  The difference is the current draw changes to make sure the power stays the same.

So as long as the voltage stays fixed (basically an infinite bus), the current will change so that the power input remains fixed.  If the power fluctuates with current draw, the something is wrong.

If you take the same piece of equipment and change the input transformer so that in one case it takes in 120 Volts and the transformer/power supply in the equipment converts that voltage to the necessary internal power supply voltage and in the other case install a transformer that takes in 240 Volts and does the same thing.  There is no way there should be any difference in the operating characteristics and sound of that equipment.  Power is power. Volts are Volts and Current is Current.  

for high power amps, yes, using 240 Volts is better just because of reduces line losses on the power line and you won't need huge power cables at 240 Volts.

So, take 1000 Watts power as the requirement.  P = V x I remember?

If the line voltage is 120 Volts, then the current would be 8.33 Amps.  If the line voltage is 240 Volts, then the current would be 4.17 Amps.  So you see the savings is in the size of the conductors because the current draw is lower you don't need massive conductors when using higher voltage.  Also, keep in mind that Power and Voltage have no phase angle.  The current in this case has the phase angle based on the impedance of the circuitry.  So, with 120 Volts or 240 Volts connecting to the same circuitry, it will have the same phase angle for the current.  

Remember P= I x I x R.  make R Z (impedance) associated with Resistance, Inductance and Capacitance impedance and the power and voltage remains fixed and guess what?  The current now has a phase angle.

Lots of technical mumbo jumbo, but the point for those that care, is that as long as the conductors are up to snuff and the power supply is designed correctly, the input voltage doesn't matter.  Power is power, Volts are Volts and Current is Current.

One other point.  Safety.  using 120 Volts, you will receive a nasty shock, but won't die unless you are standing in water or some such and can't get away from it.  In the USA 60 cycles per second is just slow enough that when the cycles reach zero, guess what?  you can get away.  Unless you are standing in water and can't get away.  In other countries, 240 Volts at 50 cycles per second is very nasty and that presents an altogether different and serious problem.  240 Volts is no joke.

enjoy

jea48,

Thanks for your reply and explanation. Of course, you are correct. Those 240V outlets are from the time whole electrical thing was redone and were made just in case, for dryer and similar appliances (not for stereo equipment). I do have a turntable with dual voltage and I switched it to 110V and it has been working just fine.