[murf]

Hello Audio Experts!

Yesterday we hit 100f degrees here in NYC, and they cut the power levels ~ 5% because of all the a/c use.  Should I watch tv instead of using my AVA Fetvalve amp when they do this?   

Murf

[avahifi]

You certainly can go ahead  and use your AVA equipment during a power brown out.

All our equipment runs just fine in low voltage situations, you might loose a bit of ultimate power output but no other bad effects.

Regards,

Frank Van Alstine

[murf]

Thanks Frank,
You build strong stuff!   
My computer lost it's video driver yesterday; I wonder if the brown-out did it....

Murf

[Wayner]

My Uglies book says that ANSI standards for 120volt line voltage is +/- 2.5 volts. That would make it 122.5 for the high side, 117.5 for the low side. No one follows this standard, of course, but what the hell.

I'm running 119.7v right now. A nice device you can purchase from Radio Shack is the Kill-A-Watt usage meter. It has a digital readout of incoming voltages. As Frank has said, there is no problem with AVA at lower voltages, much better then higher voltages.

I was running my stuff the other day when it was 102° and my voltage was hovering around 115-114. The utilities said they don't crank up the other generator(s) until there is a 5% drop, which would make it 114 volt.

Lordy, Lordy what is we gonna do?

 

[Opus Flatus]

Voltage tends to run high in Brooklyn. At least at my work location S.U.N.Y. Downstate. Unless my RCA power line monitor is out of calibration -it is showing 126 Volts A/C. Yesterday with the hot temperatures it was down to 120V.

[murf]

Thanks Folks,
My little multi-meter is showing ~ 119.3acv today.  But it's a nice 75f degrees now.  Feels much better! 
The mongrels agree.

Murf

[bregez]

These old Heathkit line voltage monitors work great.  Just plug them in to keep tabs on daily fluctuation of line voltage.  This summer has been so hot I stated plugging my Dynaco 70 amp into a variac and run it at +/-112v in an effort to keep the power tubes running cooler.  There is no distortion at the volumes I listen to.
Brad

[murf]

Lordy, Lordy what is we gonna do?

 

Well, with this heat & the subsequent power cuts, my first thought would be to protect my Fetvalve amp.  Good to know I shouldn't worry too much about it.
My second thought is to protect the mutts...

Murf

[avahifi]

The only further comment I have is that during the time of really hot days and nights, and lots of thunderstorm with loads of lightening, this seems to be the time when extreme power surges sometimes take the power supply diodes out of very old equipment.  Its a rare event, but always seems to be traced to really bad power line transient overvoltages.   Certainly it is not the time to leave your equipment turned on all the time, even when you are not using it.  We use 1000V rated parts here and inrush current limiters, but a good computer grade spike absorber would be a good idea to use.

Frank Van Alstine

[Wayner]

These hot days also invite line noise via inrush spikes from all of the cooling devices down stream, like AC units, but also refrigerators, freezers, dehumidifiers and stuff like that. Some have poor power supplies that may introduce DC voltage into the line, which can raise hell with HiFi equipment in general, usually resulting in some "pops" or other nasties, and even induce some nasty hum in some transformers.

Wayner

[yeldarb]

Stuck my cheap meter in the outlet my old AVA 4i is on, yesterday.  Voltage read 123.  Checked a few others all about 123 give or take a .10.

What adverse effects will this have on my hifi stuff?

[Wayner]

None.

Wayner

[festuss]

nominal line VAC is 125VAC. My line has been as high as 127VAC, severe hot spell goes to 115.  Most of the time is 123.  I am very close to the mains transformer on the pole, and only 2 houses are on the one transformer. Any quality equip can easily take + - 10% Utlilitys usually maintain +3% of nominal.  They are extremely good here.  For the last 25 years power might have been out 3 times for 5 hours.

[festuss]

The only further comment I have is that during the time of really hot days and nights, and lots of thunderstorm with loads of lightening, this seems to be the time when extreme power surges sometimes take the power supply diodes out of very old equipment.  Its a rare event, but always seems to be traced to really bad power line transient overvoltages.   Certainly it is not the time to leave your equipment turned on all the time, even when you are not using it.  We use 1000V rated parts here and inrush current limiters, but a good computer grade spike absorber would be a good idea to use.

Frank Van Alstine

I have 3 Furman Power factor units and3 Furman line protectors rack units powering my 4 P500 Hafler/AVA amps , and all the rest of the stuff. When storms are coming through they are turned off so everything is disconnected from line.  And straight power failure one off is fine, it's those off on, droops, then back up off on again that destroy stuff like refrigerator tv's .  When not in use the Furmans are off with their line switches, so the entire system is off the line.  The Furman power factor units actually do drop line current by a few hundred mA that the large very inefficient transformers suck lots of inductive wasted power. The furman puts a big motor cap across the line and elaborate protective ckts...great units pro grade, not audiophile BS.

[Wayner]

nominal line VAC is 125VAC. My line has been as high as 127VAC, severe hot spell goes to 115.  Most of the time is 123.  I am very close to the mains transformer on the pole, and only 2 houses are on the one transformer. Any quality equip can easily take + - 10% Utlilitys usually maintain +3% of nominal.  They are extremely good here.  For the last 25 years power might have been out 3 times for 5 hours.

No, it's not. It's 120 by design.

[JerryM]

In my experience at 120 volts, a 10% up or down swing is typical, and assured by most power companies. Lighting (which, outside of the home, is typically 277 volts) is 5.8% up or down.

Frank has always designed within these parameters, as have many other savvy folks. Noise on the line is typically more important to target, and can be prevalent at exactly 120 volts if not dealt with accordingly.

Have fun,

Jerry

[festuss]

Mine is always closer to 125.  As high as 127.  Over the years power companies are moving it up, as it's more efficient to be at 127 eventually.  The system is becoming over loaded, so a slightly higher voltage will increase capacity, without having to have larger lines.  less current more volts same power.  127V is the eventual setting.  It used to be 110 if you recall decades ago, maybe back in the 50'S.  My main service is upwards of 247 across both legs.   No such thing as 220V into a residence, always closer to to 240+. If you are running 115 on none heavy load days, there is a problem.  They usually drop it back to around 115 around hear on extreme hot days, with lots of AC going.   http://microblog.routed.net/wp-content/uploads/2007/09/voltage_tolerance.pdf