Is there a real difference?

Anders Brundell · From: Falun, Sweden

It seemes to me that amps - especially tube amps - sounds different run on 230 VAC 50 c/s here in Sweden, than on their standard electric diet back home in USA. Is it my imagination, or is there a real difference? There must be a bunch of Forumites who have played over here, who are able to tell.

Bill Llewellyn · From: San Jose, CA

Anders,

It should be the same. The only difference between the two AC standards in the audio gear I've worked with is that the amplifier (or other gear) power transformer has a different number of turns in the primary winding. The resulting secondary (stepped-down/up) internal voltages are the same. There's no differentiation for the 60Hz versus 50Hz.

Maybe the air is cleaner in Sweden so the music just sounds better?

Susan Alcorn · From: Baltimore, MD, USA

I think everything sounds different in Europe.

Curt Olsen · From: St. Paul,Mn USA

There may be somewhat of a small tone change at high power levels as the current ripple in the power stage will be greater.50 Hz does not update the DC link as fast as 60Hz.I have designed high power servo drives for 40+ years, and have found that a drive running on 50Hz must be tuned different than one on 60Hz.

CrowBear Schmitt · From: Ariege, - PairO'knees, - France

i'm w: ya' Susan.
Steelin' Europa...

Keith Hilton · From: 248 Laurel Road Ozark, Missouri 65721

This subject made me break out some old text books concerning frequency, inductive reactance,capacitive reactance,impedance and things related to the 60Hz---50Hz difference.
First,a inductive reactance is directly proportional to the frequency of the AC supply source. The actual inductive reactance in ohms is equal to: 2, times 3.14, times the frequency of the AC in hertz,
times the inductance in henries. Current lags behind voltage in a AC inductive circuit. In a circuit containing both inductance and resistance, the AC current will lag the voltage by an amount between zero and 90 degrees. Capacitive reactance of a capacitor is inversely proportional to the frequency of the AC supply source. The capacitive reactance of a capacitor can be calculated by: dividing the product of 2, times 3.14, times the frequency, times the capacitance in farads--into one. Current leads voltage in an AC capacitive circuit. With resistors, current and voltage are in phase. The net reactance is the difference between the capacitive reactance and the inductive reactance. Impedance is then the squre root of the sum of the total resistance squared and the net reactance squared. Impedance of any circuit can be measured at any frequency within the range of a signal generator. Inductive reactance increases as the frequency is increased, but capacitive reactance decreases with higher frequencies. When inductive reactance equals capacitive reactance a state of, "resonance" is created. This happens at the resonant frequency of a curcit. In real life seldom does a 120 Volt 60Hz power supply to a building read exactly that. It may read 132 volts or 118 volts. The frequency may also vary. In a 240Volt, 60Hz, system each 120 volt leg is 180 degrees out of phase. That's why you don't need a neutural wire to power something with 240 volts. In a 208 3-phase system each phase is 120 degrees out of phase. Are these phases "exactly" 180 or 120 out of phase, not exactly. Most electrical systems in buildings have a lagging-power factor owing to motors, coils, fluorescent lighting ballasts, and the like. In most cases, a low lagging power factor is corrected by connecting capacitors in parallel with the system. In the "real" world, no telling what you are plugging into, when you plug into a receptical in the United States or Europe. What you get from any electric supply can vary greatly. Yes vary greatly, and we havn't even talked about transient spikes. I think Curt summed it up good, when he said you might hear a slight difference. In my opinion the sound can be changed more by other factors like air pressure and humidity. Air pressure and humidity change every day. That's why the weather man gives the barometeric pressue and humidity reading. Anders, I think you worry about the wrong thing. People in Countries with 240 volt 50Hz systems, who use products designed for 120 volt 60Hz systems need to be more concerned about failures instead of tone. The "real thing" they need to be concerned with is grounding everything to one point. The "real" concern should be about ground potential. All transformers "must" be grounded to one point. Otherwise you have a floating ground or grounds. Since a guitar cord connects different devices, each device could have a different ground potential. This means, in "layman's" terms, 120 volts or even 240 volts could come down your guitar cord. This much voltage coming down a guitar cord can, and will, fry electronics. Anything above 30 volts is dangerous to the human body. Every transformer, every power supply, and every conductive case a guitar cord plugs in "must" be grounded to one point. This is called "star" grounding. This is even more important in countries in Europe where the voltage is 240. A common mistake people make is mixing 240 volt devices with 120 volt devises, and even smaller volt devises, when the transformers are not grounded together at one point. People lift, or remove grounds, to get rid of ground noise, or ground loop noise. This is extremely foolish as it will eventually result in damage to electronic equipment. It can also result in a nasty shock or even death.

Anders Brundell · From: Falun, Sweden

Thanks, everyone!

You have given me a lot to think about and some to laugh at - and who can ask for more?

Anders

Ricky Davis · From: Bertram, Texas USA

Gosh I haven't noticed any difference in the sound from the 18 times I've been to Europe.
I've used a Twin from there; and a twin from the states with a converter....and sound wise...it sounded just fine and didn't notice any power prob or tone prob; as compared to my amp here in the states.
Ricky

Donny Hinson · From: Glen Burnie, Md. U.S.A.

Thanks, Keith.

All good info...except for the statement about accuracy of the frequency of the line voltage. In this country, that's one we usually don't have to worry about! The utility companies keep that accurate to a tiny fraction of a percentage point, and that accuracy translates to the basis of the accuracy and reliability of many electronic devices, from the synchronous motors that run clocks, projectors, and most turntables, to stroboscopes and other electronic gear.

Keith Hilton · From: 248 Laurel Road Ozark, Missouri 65721

Yea, I did get a little carried away with my answer, Donny, I almost wrote a book. Sorry Donny, I don't agree with you. Synchronous, that is one big word. I never saw two clock motors run the same speed, even if they were ,as you say, synchronous. Maybe that is why clocks have speed adjustments on the back. What kind of projectors are you talking about? What kind of turn tables are you talking about? I thought record players went out years ago.
Looked all over the University Electronics Lab for a Stroboscope and couldn't find one. Perhaps you meant,"oscilloscope". Donny, glad you agreed with the real point I was trying to make in my post. That is the importance of grounding all 240VAC and 120VAC transformers to a central point so that these voltages can not come down the guitar cord. In Europe it is easy to mix 240 volt devices with 120 volt devices. If 240 volts came down your guitar cord, your steel might become very synchronous.

Bill Crook · From: Goodlettsville, TN , Spending my kid's inheritance

Keith....

Yea, he did mean "Stroboscope"....
Case in point here would be a "Peterson" strobe tuner. A very hi-percesion(sp?) unit,not normally affordable by the layman. These units generally start out at around $500.00 and go up from there. I've had occasion to see and have use of them. No need to go into detail here,but while they are 120 volt,60 cyc powered devices,they arn't dependant upon the 60 cycle A.C. freq for a standard.

As for the phono motors, (read this as turntable) again unless you are into "pro" type gear, the motors for these devices are of the synchronous type,dependant on the A.C. line freq of 60 cycle. To the average layman, this is far more than acceptable for his use. Most people cannot hear the difference of a 3-4 cent change in pitch while listening to a audio program. (Not just a single 440 cycle tone) To acheive a 4 cent deviation in tone, the A.C. line freq MUST change at leat 3+- or more cps. A swing of that magnitude just isn't allowed by the power Companys as it would play havoc with Indrustrail equipment.

Keith Hilton · From: 248 Laurel Road Ozark, Missouri 65721

Bill, please do go into detail and tell us what you know about the Peterson Strobe tuner. I never saw one of these guitar tuners used as a electronics test instrument. Maybe you can fill us in? Bill, you seem to know a lot about industrial equipment. Can you give us an exact example of how frequency change would,"play havoc" in a industrial situation?

Donny Hinson · From: Glen Burnie, Md. U.S.A.

The operating speed for most AC motors is goverened by the number of poles in the motor, and the frequency of the supply. If it were not, then running a motor designed to run at the same speed on either 110v or 220v would be impossible. Increased voltage doesn't control the speed, but the supply frequency does. Other factors come into play, but suffice it to say that this is why a motor (for instance, the one in your home heating and air conditioning system) runs at a no-load speed of 1725 R.P.M. They don't say "about 1700, more or less".

Before digitally controlled motors were designed, the AC supply was responsible for all the accuracy in electro-mechanical equipment. Everything from clocks, phonographs (excuse me, turntables for you younger guys) compressors, machinery, MOVIE projectors...anything that had to run at a precise speed was governed by the accuracy of the frequency of the AC supply. The accuracy of the line voltage frequency is routinely held to about .05 percent. That's 1/20th of one percent! Not much by today's digital standards, but pretty good for the "old days". It gave us clocks that were accurate to within less than a minute a month (which, by the way, is about all Rolex will guarantee a multi-thousand dollar watch for). Also, most all O-scopes still have a 60Hz sweep setting, which lets you check for drift of the internal (crystal-controlled) sweep circuit.

As far as electric industrial equipment goes, well...most of it has a motor, and that motor must operate at a reliable speed to achieve the proper function. I shouldn't have to elaborate on something that basic.

Stroboscopes are designed to measure speed of moving machinery (motors, turntables, and such) and to "stop" visible motion of machinery for analysis purposes. Musicians with some years on them will also remember the old strobe tuners, which were the "standard" before the digital stuff came along (only a couple of decades ago).

An yes, Keith, the synchronous (aka Telechron) clocks had a speed adjustment...and it performed the same function as the pitch adjustment in today's most modern digital tuner...it corrected for drift (fluctuations).

I think that about covers it.

Keith Hilton · From: 248 Laurel Road Ozark, Missouri 65721

Glad you filled us in with all your knowledge and experience. Interesting, to say the least.

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