Receptacle Voltages?

[Cody]

Hey everybody, I have a general question that I've had trouble finding an answer for. How much voltage is too high to have at the wall receptacle for amps, pedals etc.? Somebody told me that the voltages in my receptacles were too high at 126-127 volts AC. I thought most electronics had power converters that change the voltage to DC and the proper amounts, I guess there could be an excessive point but what would that be?

I'd really appreciate any info cause i'd hate to damage my equipment.

[Chuck H]

"Somebody" is right. And wrong. Excessive wall voltages can be a problem with some amps. Some devices DO have regulators that correct operating voltages. Most tube amps DO NOT. For example, a vintage amp designed with a 110V primary that has a 4X step-up at the secondary will now have an 68 volts of HV. If the amp was already pushing the limits on the stock circuit, like a pair of el84's at 340Vp in class A, you now have 408Vp idling at over 100% dissapation. You'll probably blow something up. There are also some power transformers that fudge high on things like tube filament taps. If the PT has a 115V primary and is designed for 6.8V on the filament tap you'll get about 7.5V on the tube filaments. That's over the max tolerance for this circuit and may cause premature tube failure. But in general, most devices designed for 120V will be fine with the extra 7V on the mains side.

If your using vintage gear this would be a good subject to learn a little about. If your using modern gear don't worry about it.

P.S. Not sure why, but wall voltages have been going up and up for a long time. Some PT manufacturers now offer 125V primaries even though 120V at the receptical is the (much ignored) standard. And, FWIW, 127VAC at the receptical isn't uncommon. It probably fluctuates during the day.

[Cody]

Well that makes me feel better, I only use modern equipment. I checked the voltage at the wall throughout the day and it seems to stay at 126-127VAC. Thanks for your input

[J M Fahey]

Wall voltage has been creeping up from the 40's on.
Just check old Fender schematics and they gradually showed 110/112/115/117/120V
Now it's 127V on new households.

[Chuck H]

I've seen new condo complexes powered through giant cyclic regulation. From what I understand, the principals are like the FET regulators used in variable speed power tools. Which messes with the actual Hz! people who live in these places do have problems with noise. The voltages are are a nice steady 120VAC though!

[soundguruman]

I've seen new condo complexes powered through giant cyclic regulation. From what I understand, the principals are like the FET regulators used in variable speed power tools. Which messes with the actual Hz! people who live in these places do have problems with noise. The voltages are are a nice steady 120VAC though!

The reason is that commercial power companies raised the transmission voltage, to avoid installing thicker wires, to serve more customers. It's a cost cutting measure.
The higher the voltage is, the thinner the wire can be.
In CA. they started using 1,000,000 DC through the transmission lines, and converting it back to AC at the end, because somehow it saved them money. Although we no longer have pure sine wave power, but stepped sine wave, like an inverter.

[J M Fahey]

1 MV DC long distance lines?
Interesting. Care to share any link showing that?

[soundguruman]

1 MV DC long distance lines?
Interesting. Care to share any link showing that?

Believe it or not forum bully,
All information is not posted on the internet.
Why don't you call PG&E, and ask them yourself?
Since it's "so" important that you attack me, and prove how smart you are.

[J M Fahey]

A 1 Mega Volt transmission line, which by definition feeds hundreds of thousands people, surely is not "hidden".
Whether it's DC or AC.
It's *big* news ... if it exists.
Again, care to provide a link?
Even if a page of PG&E

[km6xz]

Juan, it is not hidden at all, a middle level system of +500kv and -500kv DC transmission lines plus an incredible grounding system that at the southern California terminal end, uses the Pacific Ocean as the ground return is just one example.

But there are many systems in operation all over the world that are bigger. It was a system developed in the 1930s by the Swedish electric company. President Kennedy authorized the project to convert a number of major urban regions to DC long distance transmission in 1960. They used mercury vapor tubes for the inverters back then but about the 1980s switched to optical triggers thyristors and IGBT...big ones. But the first DC systems were in Sweden and northern Europe and the first large system was in the USSR opened in 1951. China and Brazil both have has a 6GW!! DC systems and the longest is 2500km in Brazil. The highest static tension is about 600kv per line, or 1,200,000 volts between the lines used in several systems.
Most run differential with two exposed steel core aluminium cable or split referenced to their ground system, which lowers the tension to 500-600kv but doubles current.
If you live in California, Northern Europe, any island or in Siberia or China, there is a good chance your electricity is coming from a high voltage DC transmission system.
Right off the bat, without changing cables, a DC system can handle 130% higher current since it has higher RMS value than the same peak voltage AC system. DC is particularly good for submarine systems because of the lack of cable capacitance that AC systems have to deal with. It is used in inter-ties between different distribution networks while keeping isolation between them, reducing the chances of cascading blackouts, or worries about synchronizing between different AC system phase along a long transmission route. They even supply current to systems using different line frequencies, 50 hz and 60 hz countries can be fed with the same long range transmission system.

[soundguruman]

I first learned about the 1M volt DC system from Professor Bret Allen at Cuesta College.
He was a Senior engineer for PG&E for many years.
You are welcome to call him:
805 546 3917 ballen@cuesta.edu
Mainly we were engaged in a conversation about how solid state devices could be used to create a stepped sine wave, from DC.
It turns out that it is more efficient to run DC the transmission lines and convert it to a step sine wave at the receiver end.
As the stepped wave passes through more and more isolation step down transformers, the edges are rounded off,
and it looks like a regular sine wave at the end user. The steps are basically choked out by the inductive opposition to a change in current.

And- it's not hidden, I never said it was. It's in plain view for all to see.
For some reason they save money on the wire by doing this, and it works out to be more cost efficient.
Aluminum wire, well there's a lot of loss there. But I think we're basically stuck with it.

Amazingly, I was amazed by this- between the commercial power plant and the end user,
63% of the energy generated is lost in the wiring, which is aluminum.
And so, they keep looking for ways to improve that, even slightly.
AND you can see now how inefficient commercial power really is.

This, by the way, is why electric cars are really much less efficient than the manufacturers are claiming.
If you calculate the losses in the wiring, your MPG is falling fast.
These plants are burning oil and coal to generate...the losses in the wire are huge, and so you are actually
just moving the source of pollution from the car tailpipe to the power plant.
And the pollution turns out to be more, not less as claimed.
And so, there is no such thing as an emission free vehicle, although the manufactures want you to think so.

On the other hand, if we generate from wind, solar, geothermal, hydroelectric, etc...the situation looks much better.
(don't talk to me about nuclear, it's EVIL)
AND if the energy is produced at the point of usage, we have eliminated all those losses from the long wires.

And so, there may be hope for us after all, although in the USA, only about 3% of our energy comes from alternative sources.
70% from burning coal, etc...

Here's something:
http://en.wikipedia.org/wiki/Pacific_DC_Intertie
I wonder if Mercury Arc Rectifiers would be good for a guitar amp?

And yes it is FOUR 500KV lines, which means that if it is measured between any two lines, you have 1,000,000 volts DC.
so the 1M volt figure is accurate.

[soundguruman]

Juan, it is not hidden at all, a middle level system of +500kv and -500kv DC transmission lines plus an incredible grounding system that at the southern California terminal end, uses the Pacific Ocean as the ground return is just one example.

But there are many systems in operation all over the world that are bigger. It was a system developed in the 1930s by the Swedish electric company. President Kennedy authorized the project to convert a number of major urban regions to DC long distance transmission in 1960. They used mercury vapor tubes for the inverters back then but about the 1980s switched to optical triggers thyristors and IGBT...big ones. But the first DC systems were in Sweden and northern Europe and the first large system was in the USSR opened in 1951. China and Brazil both have has a 6GW!! DC systems and the longest is 2500km in Brazil. The highest static tension is about 600kv per line, or 1,200,000 volts between the lines used in several systems.
Most run differential with two exposed steel core aluminium cable or split referenced to their ground system, which lowers the tension to 500-600kv but doubles current.
If you live in California, Northern Europe, any island or in Siberia or China, there is a good chance your electricity is coming from a high voltage DC transmission system.
Right off the bat, without changing cables, a DC system can handle 130% higher current since it has higher RMS value than the same peak voltage AC system. DC is particularly good for submarine systems because of the lack of cable capacitance that AC systems have to deal with. It is used in inter-ties between different distribution networks while keeping isolation between them, reducing the chances of cascading blackouts, or worries about synchronizing between different AC system phase along a long transmission route. They even supply current to systems using different line frequencies, 50 hz and 60 hz countries can be fed with the same long range transmission system.

He should be working on interstellar travel,
not guitar amps.
What a waste of talent.

[J M Fahey]

SGM , thanks for posting a link.
If you had simply done it when asked for, you could have saved about 55 to 60 lines of useless text.
Was it *so* difficult?

KM6XZ, I was also amazed that SGM could not offer proof, beyond the ridiculous idea of *phoning* somebody.
In fact I guess he googled the Wiki article *after* you quoted it.
Just sayin

[olddawg]

I like modern nuclear power. Clean and efficient if implemented correctly.

[Chuck H]

But SGM did, apparently, know about it prior to the need of offering proof. That IS significant IMHO.

[km6xz]

I did not quote anything, I read about the these systems for years in IEEE Spectrum and paraphrased what has been in the journals for a long time. There is a lot of tech information on these, with hundreds of projects on the drawing boards so it is of interest to trade journals and their advertisers.
There is even an interesting exhibit at the Communications Museum here that deals primarily with A.C Popov but also has electrical system and space communications sections. They have lots of photos and one insulator from a Siberian inverter station. It is two stories high. The USSR was always interested in power transmission efficiency because of the vast distances to cover between sources and population centers. They were pretty advanced in HV AC also and developed suitable materials for million volt systems first.

[soundguruman]

Forum Bully,
Actually I was answering a question.
I am not here to gain your approval, and I don't care if you approve or not.
I was not posting this information for you, but for anyone else BUT you.
Professor Allen, being a grid power engineer, could certainly explain this far better than I could.

[soundguruman]

Chucky,

I am a licensed electrical contractor, a certified general electrician, and believe it or not, I know a little about my subject.
Stay skeptical, my friends.

[Steve Conner]

HVDC links certainly do exist, we are working on condition monitoring equipment for a 2GW one right now.

However, the "stepped sine wave power" is a bit of an exaggeration. HVDC converter stations do indeed work with pretty nasty waveforms internally, but they have harmonic filter yards almost the size of a football field to notch out the worst current harmonics, so the power quality at the grid interface is really no worse than with ordinary generators. They have to do this because there are legal limits for distortion on the line voltage, as any licensed electrical contractor would know.

Utilities commonly allow the peaks of the line voltage to flatten off within the limits allowed by the distortion spec, but that has nothing to do with HVDC power transmission. It's caused by rectifier loads without power factor correction, but it also helps to improve the power factor of said rectifier loads, so they just let it happen.

[soundguruman]

I like modern nuclear power. Clean and efficient if implemented correctly.

Nuclear Energy is the most foolish and irresponsible method of generating electricity ever conceived by humans.
You should quote me on that.

[Kazooman]

Hey everybody, I have a general question that I've had trouble finding an answer for. How much voltage is too high to have at the wall receptacle for amps, pedals etc.? Somebody told me that the voltages in my receptacles were too high at 126-127 volts AC. I thought most electronics had power converters that change the voltage to DC and the proper amounts, I guess there could be an excessive point but what would that be?

I'd really appreciate any info cause I'd hate to damage my equipment.

I play around with several vintage amps and tape echos. The voltage thing drives me nuts at times. The tape echos have multitap transformers in them, with a half dozen choices. However, the two I could use are 110 and 130 and my line voltage hovers somewhere in between. So, I can either run the unit a bit too hot or a bit too cold.

I finally decided to address the problem with a "buck-booster" transformer (autotransformer). Commercial units have all sorts of choices on the wiring to match the input voltage to the desired output, but they do cost money. I built my own from a small transformer I had lying around. There is a good general article about this at the geofex website: http://www.geofex.com/index.htm Select "Tube Guitar Amp Tech Pages" from the lefthand column and then Vintage AC power from the menu. Very simple and it works great. There does remain the problem that the line voltage does vary somewhat depending on local usage.

[soundguruman]

HVDC links certainly do exist, we are working on condition monitoring equipment for a 2GW one right now.

However, the "stepped sine wave power" is a bit of an exaggeration. HVDC converter stations do indeed work with pretty nasty waveforms internally, but they have harmonic filter yards almost the size of a football field to notch out the worst current harmonics, so the power quality at the grid interface is really no worse than with ordinary generators. They have to do this because there are legal limits for distortion on the line voltage, as any licensed electrical contractor would know.

Utilities commonly allow the peaks of the line voltage to flatten off within the limits allowed by the distortion spec, but that has nothing to do with HVDC power transmission. It's caused by rectifier loads without power factor correction, but it also helps to improve the power factor of said rectifier loads, so they just let it happen.

Actually, every electric contractor in CA would not know that.
We are intentionally broken up into "specialties" by the state educational system.
My specialty is electrical / electronics. Like controls, sensors, audio video, etc...
Another specialty could be grid engineering, etc...filtering harmonics, power factor correction, etc...
This is because the state wants knowledge separated among many people, into specialties.
One contractor does not invade the territory of another contractor, and competition is minimized.
Seems silly, I know.

I have no doubt that the educational system in other parts of the world is much better.

[soundguruman]

Yes many times you are better off lowering the voltage.
Many people use a variac instead of a fixed buck boost.

[DrGonz78]

I have read of power wiring in houses that were a bit above 120 Volts AC. It was on a ghost hunters type show and then an electrician was called up to come fix the problem. Don't forget that wiring in many older houses have not been changed in 50 years... In that episode of that ghost type show the TV kept turning off on it's own, so there was a problem w/ the lines running to hot to the TV. How did we all start running off to HVDC land? Either way this forum is always entertaining and educational!! All I can say is I can't wait to check this thread in another 24 hours.

[Steve Conner]

For extra Frankenstein vibe, you might like to try a motor-driven variac to regulate your line voltage automatically.

For a more modern option, some computer UPS units offer regulation using relays and buck-boost taps on the internal transformer. The really high-end ones convert the mains to DC and regenerate it as a pure sine wave using an inverter, hopefully with a very close voltage tolerance.

[pdf64]

Wow, how interesting, I thought that the ac vs dc transmission / distribution system debate had died 100 years ago, with Edison and Tesla.
Pete

[soundguruman]

I have read of power wiring in houses that were a bit above 120 Volts AC. It was on a ghost hunters type show and then an electrician was called up to come fix the problem. Don't forget that wiring in many older houses have not been changed in 50 years... In that episode of that ghost type show the TV kept turning off on it's own, so there was a problem w/ the lines running to hot to the TV. How did we all start running off to HVDC land? Either way this forum is always entertaining and educational!! All I can say is I can't wait to check this thread in another 24 hours.

Perhaps you did not realize that ALL TV reality shows are scripted and 100% FAKE.
Sorry to interrupt your disillusion.

[soundguruman]

Don't EVEN use the word "edison" in a sentence with Tesla.
Edison was a phoney, a rip off artist, and a total jerk.
Tesla was a Genius. He was the architect of the modern world.

Indecently, Edison did not invent the light bulb either. Surprise.

[Jazz P Bass]

.Indecently, Edison did not invent the light bulb either. Surprise.

No he did not.
What he did do and it took many different iterations, is make a filament that lasted more than a few hours.
(he ended up twisting bamboo fiber around the metal filament)

[soundguruman]

No he did not.
What he did do and it took many different iterations, is make a filament that lasted more than a few hours.
(he ended up twisting bamboo fiber around the metal filament)

I think it's about time to straighten out this story.
Edison had absolutely nothing to do with the invention of the carbonized bamboo filament.
He in fact stole the idea from another inventor, and claimed that he invented it.
That inventor successfully sued Edison for patent infringement.
Edison NEVER sold a single light bulb. The patent office banned him from doing so.
In fact he was sued again and again for infringement, by several REAL inventors.
His "invention" of the light bulb was in fact a complete grandiose failure.

It was the Edison controlled media, that convinced the public that Edison invented the light-bulb.
And many people still believe the deception, to this very day.

Edison in fact, fabricated an elaborate story: That he had employed dozens of technicians who worked day and night to "find" the perfect filament.
In the end, that's all it was-a story, it never happened.

The REAL inventor of the incandescent light bulb: Warren De La Rue, an Englishman
The REAL inventor of the carbonized bamboo filament: Albert Swan
The REAL inventor of radio: Nicola Tesla (also remote control, robotics, wireless power transmission, brush-less AC motors, etc...etc...)

And now I have given credit, where credit was due.

[Enzo]

Soundguruman, please go back and reconsider posting your professor's name and phone number. It is bad enough putting up someone's email address, but really, do you think this man will appreciate your having put his name and phone number on the internet? if you respect the professor at all, I highly suggest you edit your post to remove that personal information, unless the man had specifically given you his permission to post it.

This is an honest request, and has nothing to do with any lack of respect I may have for you personally.

[Chuck H]

and has nothing to do with any lack of respect I may have for you personally.

I thought I was going to fall out of my chair!

[Jazz P Bass]

Actually what makes Edison's name appear alongside 'lightbulb' is the attention that he gave to making a filament last. So he succeeded in creating the bulb that was cost-effective and had long life.
(James Watt greatly improved the efficiency of the steam engine cycle. Everyone thinks that he invented it)
What Edison really missed was the black spot that appeared on the glass.
If he only would have passed a magnet alongside it, as it was forming, he would have seen that it could be steered.
Can you say CRT.

[km6xz]

History, to be paid attention to, needs to be simplified, distilled and popularized or else it would be way too messy an affair to capture the interest of non-historians. No Marconi did not invent anything either but he did what most popular cultural heroes did, armed himself with lawyers and PR people to create an acceptable myth that made all the messy details of history palatable. The history of popular figures in science and engineering was no different than world or national histories which were re-writes of events to focus on one person, one date or one event. It seems people ignore things that are not concise and focused. A war or a inventor is much easier to describe with one date or event than the reality which is no less complex than trying to distill a whole life's work of a single human with a one word description.....only more so. It is ALL nonsense as taught and accepted but the reality would not be paid attention to at all if a simplified version was not invented.
Even the reports of "the real inventors of xxxx was zzzz" are just the same as the popularized version of distilling a vast array of events, people, trends, the social conditions of the times etc that resulted in a general field becoming distilled down to a simple short descriptor. Who invented any of these things? You could get 100, not 10,000 correct answers that are all different. For example radio was being worked on by literally thousands of people at the same time and none worked in total isolation. Each adding minor modifications to one of the many branches of inquiry so a concept evolved from tiny incremental steps, none by themselves that significant. Invention of general application concepts such as electric lighting, highways, stone construction, writing etc are just like the evolutionary processes of evolution by natural selection in biology.
What a child learns in school is primarily the views of people who made an effort to control the image and shape opinion through popularizing, publicity, courts, and personality. In the late 19th century "invention" primarily became the domain of the courts and the winners were rewarded handsomely with wealth and fame, and the losers, often economic ruin. Edison was the same manipulator of opinion that Steve Jobs was, neither really invented anything but both popularized other people's work to reap the benefits, using pr, a cooperative press and the courts. Bill Gates was the same but with less "hero making" attempted.

[soundguruman]

Chuck wrote:

"I thought I was going to fall out of my chair!"

Dito