Some info on POWER

Posted on

Head Knocker
Contributor Since: May 20, 2007

Edited Aug. 09...
See the extended update of this post by using the link on the home page of this site...

Taking the chance that there are a few who haven't had a lot to do with electricity, here are a few facts, etc. that everyone hooking up gear should know.

Source power:
Any electrical/electronic gear is going to use a certain amount of wattage, or power. It is usually spelled out on a sticker or plate that gives the input voltage, frequency or Hz, amperage, and watts. The watts is the important one as that IS what will be consumed. Watts equals (roughly) volts times amps. If you have a 120 watt light it will use one amp. 120v X 1a = 120Watts.
If the voltage is less than 120, the amps will go up to make up the 120watts.
Voltage up, amps down. Volts down, amps up. The gear uses watts, not volts or amps. So, if you use a 14 gauge wire (rated 17 amps max) for a 15 amp circuit, but you have only 109volts from the socket, the amperage will be more than 15 amps. It will exceed the 17 amps rating of the #14 wire and it will melt the insulation and short out, hopefully tripping the 15 amp circuit breaker for the building circuit you are plugged into. Lesson: Use #12 wire for all power cables to your gear unless you know for sure the voltage is a reliable and steady 120volt source.

Power supplies, surge suppressors, and line conditioners:
Audio gear is expensive, even the cheap stuff. It's also sensitive to fluctuations of voltage, surges caused by lightning or heavy equipment starting up, etc. The surge strips you buy for $10 at WalMart are OK for PCs because PCs use a specially designed power supply that protects against brownouts, shorts, surges, etc. But, the surge strips aren't worth a flip for a mixer that doesn't use a switching power supply, or a bank of power amps with fuse protection only. Also, when these surge strips do encounter a surge, the varistor that is the protection burns out, but the power keeps coming. You don't even know that it isn't protecting anymore unless it's one of the better units with an indicator.
To protect audio equipment properly and safely, an Isolating Line Conditioner is needed. This unit has a transformer that doesn't change the input voltage, but simply isolates the incoming power from the load with coils of unconnected windings. It also employs solid state "crowbar" circuitry that will soak up a surge of voltage, like lightning, or unrelated equipment loads, and store that extra power to give back if a brown out or severe voltage drop occurs. Essentially it maintains the input voltage within .1%. That's 120V +- .12V, or 119.88 - 120.12Volts. Very tight control, very good protection. A 1000KVA unit is standard and rackmountable, and has ten or more duplex 120v receptacles to plug power strips into. That size unit would power a good sized PA, mixer, rack FX, desk lighting, amps, amp stacks, etc. Two of those would do a Who concert.

Voltage drop: Basically, the longer the wire or cable, the bigger gauge it needs to be. Long cables soak up voltage, which causes amps to increase, which causes heat, and more voltage loss, and, eventually, total loss of signal. 25 feet of #14 might handle 15 amps. But 100 feet of #14 won't handle 10 amps at 120 V. Also, stranded copper is the only acceptable wire type for power cables. Solid wire won't flex and aluminum won't conduct as well.

There, that's the basics for safety. I'll rant on if anyone needs more than this.

dB, feel free to do with this whatever pleases you. Move it, delete it, edit it, it is yours. :)

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Czar of Midi
Administrator
Since: Apr 04, 2002


Aug 06, 2007 07:40 pm

glen, that is a great quick bit of info. You should lengthen it out and turn it into dB for an article. Your member status will be changed to contributor if you submit an article or tutorial like that one.

Funny neither dB or myself or the other mods and such have not thought of writing that one long ago.

Two thumbs up on that one.

Head Knocker
Contributor
Since: May 20, 2007


Aug 06, 2007 10:05 pm

Thanks.

I thought that's what I did. Is there a specific place to post it to make that happen?

I've got a few more in mind.

Grounding, where, when, and when not.

Shielding can be bad.

Splice and termination methods. How to and how to not...

Signal vs. power. What defines them.

Noise and interference, ways to avoid or eliminate.

I was a USAF aircraft electrician and tech school instructor. I then designed instrument/control circuits for petro-chemical industry for 32 years or more.
Offshore oilrigs and refineries mostly.


Czar of Midi
Administrator
Since: Apr 04, 2002


Aug 06, 2007 10:10 pm

Use the contact dBMasters link and simply send it on to dB. Let him know it is for an article or tutorial and your all set.

www.homerecordingconnection.com/contact.php

edit0r
Member
Since: Aug 17, 2004


Aug 06, 2007 11:59 pm

Quote:
I was a USAF aircraft electrician and tech school instructor. I then designed instrument/control circuits for petro-chemical industry for 32 years or more.
OH Reh-heh-eaally :-D.

I'm trying to teach myself electronics and am jumping into tube amp building but getting hellas confused. I might have to build up a few electronics questions for you if thats alright?


Head Knocker
Contributor
Since: May 20, 2007


Aug 07, 2007 02:46 pm

I'm not really an electronics type. I know some of it, but not real well.

There is a whole lot more to electronics than there is to electrical.

I will, though, answer all I can and let you know when I can't. I do have a very knowledgeable source for electronics info, though. My cousin works for NASA at the facility where the solid boosters were designed in Mississippi.

Administrator
Since: Apr 03, 2002


Aug 07, 2007 02:50 pm

Yeah, dude, if you ever want to submit this as an actual article on the site, let me know, or I could just use what you have there if you want to...not sure how much time and detail you want to go into but this is great.

I add the article to the database, give you credit, reassign you as a contributor, as opposed to a standard member and prolly toss in a year of HRC Pro just cuz this rocks.

Head Knocker
Contributor
Since: May 20, 2007


Aug 07, 2007 03:02 pm

dB,
I just submitted it to your "contact dB Masters" link as a FAQ, as it wouldn't send as anything else.


More to come...

Glenn

Administrator
Since: Apr 03, 2002


Aug 07, 2007 03:12 pm

Cool, i'll get it later tonight and put it up in the next few days...I just sent myself a ton of emails from each subject option...they all worked...weird...dunno why they didn't for you.

Head Knocker
Contributor
Since: May 20, 2007


Aug 07, 2007 05:44 pm

My PC has some wierd things happen. Like getting logged off, can't send to a category, I can not play Google videos no matter what I do, youtube movies work fine,,,,,

I have two PCs and they do not have the same personalities.


Twilight Zoned or just Too Rolling Stoned.


Czar of Midi
Administrator
Since: Apr 04, 2002


Aug 07, 2007 08:17 pm

Hey glen, dB can attest to the fact I went through a period of having a possessed PC from hell as well. It would do strange things, like boot up in the middle of the night and such. At the time my youngest son was like 5 or 6 and he was into Pokeman. He heard dB and I talking about it being something with the electrical parts of the PC that were causing it to freak out and such.

So to solve the problem, when I was installing a new PSU in it he handed me a small Pikachu, which is of course and electric Pokeman. We sat it right on the PSU with two sided tape. Viola, I have not had any issues since then at all. That was like 8 or 9 years ago I think. It is still running like a champ. I t gets rebooted regularly but hasn't been shut down for years other then a moment or two to clean the crud out.

Amazing what a child can do with a toy, or maybe its just voodoo.

Prince CZAR-ming
Member
Since: Apr 08, 2004


Aug 08, 2007 01:34 pm

Hey CS, i might be able to help a little. I've done a fair bit of research in the past, maybe not great, but it might be helpful.

I will admit though, I never did get into load lines and such, though I've read that it's not as bad as it seems.

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