# Powered Monitors question



## Sopris (May 28, 2017)

This may seem like a silly question but I want to make sure.

I'm reconfiguring some things in my studio and I need to extend the length of the IEC cable coming from my monitors, is it a bad idea to plug the IEC from the monitor into a 3 ft. extension cord then to the power strip?

Cheers!


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## charlieclouser (May 28, 2017)

That will be fine. 

You can also get replacement IEC power cables of just about any length from MonoPrice, and they're very cheap. They are listed as "pc power cables" on this page:

https://www.monoprice.com/product?c_id=102&cp_id=10228&cs_id=1022801&p_id=5279&seq=1&format=2

I bought a massive pile of them, in lengths from one foot to 25 feet, and connected all of my speakers to a single power strip so I can light up the whole set from one switch. The short ones are great for keeping the inside of a rack nice and tidy.

Just check what gauge the original cable is (12awg, 14awg, etc.) because you don't want to replace a thick / strong original cable with a thin / weak replacement cable. The "awg" rating denotes how much current the cable can safely conduct without overheating - 12awg is rated for 20 amps, 14awg is rated for 15 amps, 16awg for 10 amps, and 18awg is rated for only 5 amps. Most originally-supplied IEC power cables will be 14awg, and most power strips and wall outlets in your home will probably be rated for only 10 amps. Using a higher-rated cable is not a problem, so using 14awg IEC cables (rated to conduct 15 amps) plugged into an outlet or power strip that's only rated for 10 amps is fine. For reference, 20 amps is a LOT of current, and only the most monstrous UPS power supplies or big power amps will need this much in a studio environment. I have six Dynaudio AIR speakers connected via 14awg IEC cables (rated at 15 amps) to a single metal Belkin power strip (itself rated for 15 amps) and plugged into a single outlet in the wall that's rated for 10 amps. Long or short doesn't really matter until you get to 50 or 100 feet or more. Here is a page describing the various "awg" ratings, but it's a little technical:

https://en.wikipedia.org/wiki/American_wire_gauge

For extension cords this isn't usually a problem, unless you're using one of those thin, two-wire extension cords with the three-outlet blob on the end that only has two-prong outlets - these are "lamp cables" and are intended for low-current appliances like lamps and such, and probably not a good idea for a powered speaker unless it's a very small one! Most three-prong extension cables will be 12awg, 14awg, or 16awg (20, 15, and 10 amp ratings, respectively), but some two-wire lamp cable will be 18awg (5 amp rating) which is probably not what you want to use. In general, 14awg IEC cables are the most common and will be fine, and you can usually find the awg rating stamped or printed on the cable itself.


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## Sopris (May 28, 2017)

charlieclouser said:


> That will be fine.
> 
> You can also get replacement IEC power cables of just about any length from MonoPrice, and they're very cheap. They are listed as "pc power cables" on this page:
> 
> ...



Wow...Thank you so very very much for that incredibly detailed response!

You answered my question and then some...I think I'll be referring back to this post in the future if I ever get stumped on power.

Absolute legend, Cheers!


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## charlieclouser (May 28, 2017)

You're welcome. The only confusing part is the "awg rating" - awg stands for American Wire Gauge and, against all sense of reason, the smaller the number, the larger the wire diameter - and the more current it can handle.


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## Sopris (May 28, 2017)

charlieclouser said:


> You're welcome. The only confusing part is the "awg rating" - awg stands for American Wire Gauge and, against all sense of reason, the smaller the number, the larger the wire diameter - and the more current it can handle.


This is true...alot of things are like that, sandpaper comes to mind (I've been building a desk) larger number smaller grit, I was "lucky" in my teens to have worked at a RadioShack where that whole wire standard was fused into my brain at a young age.


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## wst3 (May 30, 2017)

To expand just a little on Charlie's fine advice...

Nothing wrong with the Monoprice cables themselves, but depending on a slew of issues too long to catalog, they won't always work as well as they should.

In an ideal world ground loops (which are a fact of life) would not cause problems, nor would noise in the ground 'system'. I don't live there<G>!

Actually, I live in a pretty decent approximation at the moment, but I downsized a lot to get here. However, I recently worked on a decent sized studio where the standard power cables did cause some problems. Not actually true, let's say they exposed other problems, more accurate.

We could have fixed all the core problems, but that would have been expensive and time consuming, instead we replaced all the various power cables with "PowerSafe" cables from Middle Atlantic. They are not as inexpensive as Monoprice, but they use twisted pairs for power, and that's a big help. 

Would I buy them first? Not sure I would, although I really don't want a crate full of unused power cables either... still, most modern gear is relatively impervious to 60 cycle noise problems, so I'd probably start with Monoprice.

The only difference is that for any amplifier I'd get the biggest cable I could, AWG#12 is not as silly as it might sound. Heat loss in cables is a function of current SQUARED... yup, squared. So if you are drawing 1 amp you might have 1X loss, but if you draw 2 amps you would have 4X loss. Not good! Now class D amplifiers (common in powered monitors) are not as difficult a load as linear designs, so even this might not be a problem, but you know, for the cost of a couple honkin-big (that's a technical term) power cables I wouldn't bother using anything smaller.

As far as safety goes, Charlie is spot on... be aware of the capabilities of your entire system. Don't use a cable rated for 10A if the circuit breaker won't trip until you hit 20A... the cable will melt first, and you don't want that<G>!

FWIW it is very easy to skip over these "silly little details"... kudos to you for considering them!


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## charlieclouser (May 30, 2017)

I agree with what wst3 said - in my case, the Dynaudio speakers (which do have class-D amps) are relatively small (Air-15's) and the ones at the far end of the 25-foot power cables are just the rear surrounds, which are typically not working very hard at all, just playing reverb tails and little fragments of sound, not pushing big SPL bottom-heavy stuff. 

Back when I wired up all of my hardware racks, I paid the price at Pacific Radio for a boatload of 12, 18, and 24 inch 12awg power cables, and that's what all the stuff like all the class-A mic preamps, computers, synths, and outboard gear are wired with, using hefty Wiremold power strips. 

Since anyone who's rigging up giant PMC stacks or similar high-current stuff will probably already know about power cables (and might even be using "exotic" stuff) I figured it was a safe bet to recommend the MonoPrice solution - as long as one obeys the basic rules of getting the awg rating correctly matched to the wall outlets, etc.

At one point back in the day there was a company in Los Angeles called "Re-Volt-Ing" (great name!) who came in to a house we were rigging up to hold an SSL 4k, plus a Neve 8028, plus six towers full of outboard gear - and we got very lucky because that house was over-built to an insane level, and every single outlet was wired through metal conduit with "home runs", where every outlet ran a separate wire inside its own conduit back "home" to the breaker panel. I don't know how common that is - my current place is wired with Romex instead of conduit (sad!) - but in that house it meant that we could pull out the old wire and replace it with fatter stuff. So ReVoltIng pulled out the old 10-amp wiring and strung every outlet in the studio area for 20 amps, tripling the size of the breaker panel and raising the total service to the house from 200 amps to 600 amps. Burly! They also added a giant balanced power system right at the panel, and the coolest part was that they color-coded the outlets so we could tell which circuit each one was connected to - orange for the consoles, red for the outboard gear, grey for synths and black for non-audio stuff like lights. It was so slick. Whoever moved into that house after us could have set up a pretty monster home theater rig for sure.

This did cost us a small fortune (thousands, but not tens of thousands as I recall). But that SSL 4k drew some serious current, and in the nineties the record company money was flowing, so what did we care? When we first moved into that house and had just set up the big speakers and a small rig to figure out where we wanted to put the console etc., I remember leaning against the wall above the outlet that the power amps were plugged into and it actually felt WARM. You could trace the path of the conduit by feeling for the warm spots in the walls! Scaaaarrrrry! Immediate system shutdown, immediate call and a blank check to ReVolting, and a week later we had no more hot walls.

I'm glad that I'm all in the box now, since my current house is wired with Romex that's stapled to the studs, so I can't pull the runs without tearing out walls - and many of the walls are concrete, so that ain't happening. No SSL 4k is going in this house! But I did have an electrician come out and calculate how much my rigs are drawing at full song, and there's no problem powering my current setup from four individual 20-amp circuits, each on a home run to the panel. This was helpful because he was able to identify that each wall in the studio had two outlets that were actually wired together as opposed to being home runs, which basically means that outlet pair number 1-B is like an extension cord plugged into outlet pair number 1-A - both on a single 20 amp breaker. So he added another pair of 20-amp home run outlet pairs to the studio - this was easy since the main breaker panel for the whole house is on the outside of one of the studio walls - and that gave me a total of four 20-amp circuits to suck from, and this is plenty for the setup I'm using now. One each for computers, synth / outboard racks, speakers, and lights. We now have 400 amps of total service to the house, up from 200 when originally built in 1995. We doubled the panel and service when we added some big HVAC equipment a while back.

I'm still unclear on whether home runs for every outlet are actually required by California residential building codes, or just recommended - and therefore skipped in most residential builds because it's assumed that you're only plugging in low-current stuff like televisions, wifi routers, and Ikea lamps to the wall outlets. I think that places like hospitals do require home runs in conduit for every outlet, but residential? I dunno. The Romex versus conduit is a bummer though - if I ever get to build from scratch it will be conduit and home runs all the way.

When your rig is a simple setup with a pair of monitors and a computer or two - everything's probably fine. But when you get to the point where you've got a bunch of class-A audio gear, maybe a console, some big-ass speakers, a rack full of slave computers, etc. - then it's worth having an electrician come out and help you figure out what the hell is going on inside your walls and breaker panel before things (walls!) start to heat up.


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## wst3 (May 30, 2017)

Short answer Charlie (as short as I can make it)...

There is a National Electrical Code (NEC) that specifies how to wire up a building, and the requirements do differ between residential and commercial, and even within each of those broad categories. BUT, the NEC is something of a guideline, state and local jurisdictions can add, or even remove, requirements. It can get a little tricky!

In Philadelphia (well, last time I had to do this) any wiring for life safety devices had to have a red jacket, and be in conduit.

For residential construction it is difficult to justify the additional cost for conduit, especially when metal clad cables provide almost all the benefits of conduit at a fraction of the cost. Conduit does make it a little easier to replace a wire run, but it is unusual to do that in the first place, especially if the house was wired well to start with.

Individual home runs, and even individual home runs to individual breakers is a different thing entirely. If I were building a house I would do that! I helped a friend with the electrical and telco design of his home and he ran individual home runs from every outlet and fixture. (Well, we did daisy-chain some of the ceiling lights, let's not be silly!) The cost for the panels to support that was prohibitive, so all the outlets in each room went to a single breaker. A reasonable trade-off, and one that can be reversed should the need arise. The electrician thought it was silly, but he was happy to be paid to do the work.

Here's a neat trick I'd love to do... the house included an outlet beneath EVERY window specifically for electric candles, and at least a dozen outdoor outlets for Christmas lights. They were scattered across the front of the house at first and second story level. Of course this same gentleman built frames for all the lights and installed mounting points so he could easily put them up and take them down.

But I digress...

Balanced Power - this is a very recent addition to the NEC. Prior to Martin Glasband's efforts that was only allowed in certain settings, most notably laboratories and hospitals. There is some benefit, but it is easier and cheaper to buy equipment that is properly designed. If all your gear uses properly balanced inputs and outputs the benefit of balanced power will be minimal, maybe still valuable for a recording studio, if the rest of the facility meets the same noise levels.

For us mere mortals running metal clad AWG#12 from each outlet to the panel is more than good enough. If you do have some gear that behaves poorly using twisted pair cable for power will probably reduce the noise problem, and running appropriately sized cables will take care of the rest.

It amuses me sometimes just how important some of the simplest (or most taken for granted) details can be.


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## Nick Batzdorf (May 30, 2017)

> Martin Glasband



Hah! There's a name from the past. I remember he had way too much fun commenting about his NAMM booth babes in between selling his balanced power boxes. He really liked both.

Anyway, I've had a fantastic isolation transformer box in my room for 20-odd years. It's called Hum Buster, made by a long RIP company called Midi Motor. The box has ten AC outlets, and in addition to isolating the power, it effectively lifts the grounds for you.

Too bad it isn't available anymore, because it's great. I had a separate circuit run into my room after the '94 earthquake, and that box goes on with one switch.

All I can find online is the patent app:

For: Isolation transformers which reduce ground loop in audio equipment. ... The mark consists in part of a design of two cylindrically shaped motors, one having curvilinear arcs flowing into the script "Midi Motor."

***

I also have to give a grumpy answer to Sopris' original question.

Both Bill and Charlie are 100% right. But just get decent extension cords and don't worry about it. Nobody will know.


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## charlieclouser (May 30, 2017)

Interesting info, wst3 - thanks for that. That house we put the SSL in back in the 1990's was a freshly built (and way-overbuilt) behemoth in an architectural style known as "coke dealer mansion" - so it wasn't all that surprising that it was done with conduit throughout. It made it easy (but not cheap) to upgrade the electrical system to handle two big consoles and all of that 1990's outboard gear.

I was a little bummed to find that my current house was wired with Romex, since that meant I couldn't pull wire, but in the end it worked out fine - each room had two or more home runs to 20 amp breakers, and with today's more compact and energy-efficient studio gear I'm well within the limits of even this "normal residential" wiring scheme - and I think most people setting up rigs at home will be as well. It's only the maniacs who are installing vintage SSL or Neve consoles who need to worry, but these guys are hopefully bringing in an electrician instead of just trying to plug in to a power strip! Although even the biggest new SSL Duality console no longer has a refrigerator-sized rack of power supplies and computers - each bucket plugs in to a standard 10-amp outlet. Amazing. Pretty significant advances in power supplies in twenty years I guess.

I did run into a situation once a long time ago when looking for a big UPS - I wanted to get a single huge one that could keep a whole room on line when the flaky power in New Orleans went out, which seemed to happen whenever the wind blew too strongly! But anything over 1500kva or so required a 20-amp connection and was only supplied with those "Hubble" Nema 10-20 connectors - and those suckers don't plug into a standard wall outlet, that's for sure. So this triggered a lot of research and education about power systems. Not all of it stuck with me, beyond a background drone of paranoia that reminds me to always check with a qualified electrician whenever moving rigs to new digs.


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## Nick Batzdorf (May 30, 2017)

Coke dealer mansion! I've only heard them called starter castles.


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## charlieclouser (May 30, 2017)

Nick Batzdorf said:


> Coke dealer mansion! I've only heard them called starter castles.



Well, this one had all of the coke-dealer accoutrements - glass block, black marble, floor-to-celing mirrors (in the dining room of all places), and all sorts of tacky crap like that. But it was huge enough to do the job, and we promptly got rid of the worst offenders! The four-car garage made a great drum room, and the neighbors were far enough away that we didn't have to do the room-within-a-room thing to make that work. Was a fun spot for a while.


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## Nick Batzdorf (May 30, 2017)

Sounds nice!


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## wst3 (May 30, 2017)

Little more background as I procrastinate on a project that is due in three days<G>...

Balanced Power (which should really be called symmetrical power since there is nothing balanced about it) starts with a really well designed isolation transformer, and most folks agree that more than 80% of the benefit of balanced power was the isolation transformer.

Out of sheer laziness I'll spare you the details, but an isolation transformer is the single best thing you can do for power in a studio setting. Well, an isolation transformer and isolated ground outlets<G>. Bang, you are 90% or better on the way to quiet power. Add to this properly balanced (not symmetrical) audio connections and you are probably 95% done. AND, if you have to skimp somewhere skip the isolation transformer, although there is still an awful lot of gear that does not have well designed gozintas and gozoutas.

The dirty little secret behind all of this is that there are several ways to build an electrically quiet studio. There are even more ways to sabotage your studio, but that's a rant for another day.

I'd have dearly loved to see your coke dealer mansion (well, not the tacky parts). I've built a couple purpose built studios where everything was done right, and it was really a lot of fun. Nothing of the scale you did. Actually not true... funny tale time!

I had a client (I didn't build his studio, just maintained it) who had built an absolutely gorgeous studio in his basement. He went so far as to lower the floor to get a little more ceiling height, and he had a separate service entrance (still don't know how he managed that one). He had what I'd refer to as an older Neve console, but come to think of it, I think it was a current model<G>. Sheesh I'm getting old. Great microphone locker, lots of great outboard gear, the whole bit. He was an orthopedic surgeon who loved music. Couldn't play an instrument, but loved to record the local jazz cats. It was a hobby he could support.

Rule #1 was I was never allowed to tell anyone about the studio. To the best of my knowledge none of the musicians who recorded there ever said anything either. He was concerned that some junkie would rob the place and put his family in danger. Fair enough, he paid well, and he paid on time, and he was a genuinely nice guy, and a pretty decent engineer.

Way back when the little Zoom guitar processor came out I was called out to repair something or other, and I was leaving for vacation the next day, and I tried to beg off, but he really was a good guy, so I ended up going over there to fix whatever it was. And he had one of the little Zoom thingies sitting on the console. As I was doing my work we talked about it a little bit. When I went to leave he handed me a check and the Zoom, all boxed up and everything. He suggested I take it on vacation and play with it. What the heck, I did. When I returned he had already bought another one and told me to keep it as a bonus.

He was a character!

But I digress... 

With a little care you can create a remarkably quiet electrical environment in most residential settings, especially suburban settings. Most homes have one or two breakers per room these days, you don't find a lot of construction where outlets are randomly connected together. And while Romex may not be the first choice, it works, especially if they really did staple it to the studs, the cable path is nice and clean.

There's little you can do to help matters until you leap to the next step, which would be an isolation transformer and you can buy one that should handle an entire small, computer centric studio. You will have to deal with the 20A plugs and outlets - which you don't find in most residential settings.

As Charlie said, have some respect for electricity, don't swap out the outlet if the wire is not sized to handle 20A. Warm walls... man that's a LOT of power if you could feel the heat through the wall and the conduit.

Enough rambling... thanks for sharing!


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## charlieclouser (May 30, 2017)

Yeah, the warm walls resulted from a 24-space rack filled with nothing but power amps - big ones. If I remember correctly, it was a stack of Bryston and Crown, set up to drive a pretty massive pair of mains in tri-amp configuration, so six mono-blocks plus a smaller Hafler stereo amp for the NS-10's - all on a single outlet. Not smart.

What were we thinking? Good thing the whole place didn't go up!


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## Nick Batzdorf (May 30, 2017)

There is a little difference between that and a standard project studio with a pair of powered monitors!

But if you have an electrician over - yes, this is a tangent - I recommend having all your wall outlets wired with a combination of switched and unswitched sockets. Things like computers, routers, and modems want power all the time; amps and synths only need turning on when you're using them.


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