AC Power Conditioning

Interested to hear any stories about various power conditioning solutions you may have tried or are currently using. What works and what doesn't? A lot of it sounds like marketing hype to me personally.

I know that a number of years ago I was in a band doing an outside gig in the parking lot at the Rock n Roll Hall of Fame in Cleveland, we were tapping into what I think equated to a generator, and the keyboard player was having a really tough time in keeping his rig from powering down and resetting. One of the other bands who had played before us let him use a Furman Power Conditioner, apparently this particular model had a function that kept the voltage consistant. All I can tell ya is the problems stopped.

BTW.. I need you to email me Kriz...

Donnyair at neo dot rr com

sorry Kriz.. not enough coffee yet..

DonnyAir at neo dot rr dot com

How old are the amps in question?

Electrolytic capacitors will dry our eventually, leaving the power supply with poor filtering. A replacement of the power supply filter caps may cure your issues.

well, according to Furman's websight, power is "contaminated".

http://www.furmansound.com/products/tech_corner/faq_powerconditioner.php

Now, what that means specifically, I don't know. And, this could very well just be a marketing thing too, although, I imagine it's a possibility that those that reside in older buildings/houses might encounter AC anomolies, but as to what, I'm not an electrician so I can't say, beyond the obvious of ground problems or something similar.

I mean, I could wager a guess and say that maybe it has soemthing to do with the phase of the power, (similar to that of a balanced audio cable vs, a non balanced), but it would only be a guess.

Is Furman's pitch all "banana oil"? I don't know. I also don't know what they mean by "contaminated", they aren't specific.

I do suspect, as I mentioned previously, that constant voltage is supposed to be pretty important, (and if my experience in the previous post is a factor, I'd have to agree that it is) especially with some of the newer technology, but as far as what a conditioner actually does in technical terms, well, I'm curious too. Any electricians out there?

D.

the Furman products are generally good, the higher end APC units are also nice. In building data centers, I've used large scale (> 250KVA) products but these are probably too much for the average home studio. :-)

If you had a real oscilloscope (hardware, not a VST plugin...) you could readily see the noise, clicks, spikes, frequency variations, and the host of crap that exists on your AC line power. it's really pretty scary... having a decently made power conditioner will clean the noise, keep the frequency and voltage steady (as much as possible depending on the load) and provide some coverage in the event of power outage or overage (usually for 15-60 seconds). This is a must have for computers and audio equipment. I use a couple of APC UPS (550 watt?) devices to filter and provide UPS but if I were to build a pro studio I would probably spring for some commercial grade line conditioning for the entire studio. The one key feature to look for: ensuring that the devices sharing the "clean" side have any noise (or other effect) filtered from the other devices on the clean side. Many cheaper conditioners ignore the shared clean side when filtering and switching devices on and off or whatever noise may be coming back through (like that visiting guitar player with the old tube amp pushing spikes back on the line every time the tube is vibrated and the grids tap the plate :-)

for pro studio owners, consider having a commercial grade device (or devices) to filter the line for the control room and studio a "must have"... Transtector, Sola/hevi-duty, MGE and a few other companies make commercial grade equipment. for the average home user - the Furman or APC devices are good enough... btw... surge protectors, etc... are not power conditioners...

Larry,

For around 13 or so years, I have been powering all of the gear in the CR with an Equi=tech balanced power supply unit. It delivers nothing but clean power.

This year, I have shelled out the money for two of these. The work greatand are worth every penny. One is used for a mic pres (Neve, TLA) rack in the CR and the other one floats between CR and Studio.

A Furman PL-8 powers my remote rack.

A CyberPower battery backup and line cleaner is used for the main DAW and Layla interfaces (2).

FWIW..... There are balanced power unit available at very reasonable prices. It is the best way to go, IMO.

Thanks - keep it coming.

Two things I've tried in the past I thought I'd comment on:

Those cheap little grounding adapters - they seem to actually make things worse in my experience. They might be ok for removing ground loop hum (sometimes) but it also seems to make the gear noisier so I've always tried to avoid that approach.

Balanced power: I bought a Furman balanced power unit a couple of years ago, tested it, and quickly returned it. It did nothing in terms of improving the sound of my gear. The thing weighed a ton What was even funnier though - I had a certified electrician in one day looking at the thing and he knew nothing about balanced power. Which is why I'm not asking these questions to an electrician.

ORIGINAL: krizrox

Thanks - keep it coming.

Two things I've tried in the past I thought I'd comment on:

Those cheap little grounding adapters - they seem to actually make things worse in my experience. They might be ok for removing ground loop hum (sometimes) but it also seems to make the gear noisier so I've always tried to avoid that approach.

Balanced power: I bought a Furman balanced power unit a couple of years ago, tested it, and quickly returned it. It did nothing in terms of improving the sound of my gear. The thing weighed a ton What was even funnier though - I had a certified electrician in one day looking at the thing and he knew nothing about balanced power. Which is why I'm not asking these questions to an electrician.

Ground-lift adapters are bad news. Any hum problems that they solve can easily be solved in much safer ways, and they have as much potential to make things worse as they have to make them better, audio-wise. And they're dangerous. If you have an electrical fire and the insurance company finds out that you were lifting grounds or using electrical devices that were not UL-listed or not up to code, they won't pay the claim and the courts will agree with them.

"Balanced power" is a red herring, audio-wise. Presuming there is any device that actually even does it, there would be zero benefit to it, and it would probably be as likely to damage certain equipment as it would to do anything else. If you don't believe me, I'll put down my beer and explain it below (take an asprin if you didn't remember high-school physics). Here's how the electrical outlet works:

You have three aperatures in a modern 3-prong outlet in the US(in other countries it's basically the same way in principle)-- a narrow slot, a wider slot, and a round hole. Presuming the outlet is UL and the wiring conforms to the NEC (National Electrical Code):

1. The narrow slot is the "hot leg," and is wired with some color other than white, green, or bare copper. Usually it's black, though it may be blue, red, or any other color. This is the leg that that transmits electrical current. It is sending nominal power of 115 volts AC, which actually means that there is 120 volts AC coming off the breaker, and it is supposed to deliver a minimum of 110V at the outlet under normal loads that fall within the wire and breaker ratings. Just like with audio, long wire runs and having multiple devices (loads) will diminish the actual voltage at the outlet. So there's some wiggle-room, and that's okay. You may hear people refer to "line voltage" as 120V, 115V, or 110V. They all mean the same thing. Different applications call for different specs, which is why different terminology is used (one device may be rated for the minimum voltage required to operate it, and another may be rated for the maximum voltage it can handle, and so on). In this discussion, we'll call line voltage 120VAC. This "120 volts AC" means that there is a +120V POSITIVE electrical charge followed by a -120V NEGATIVE electrical charge, back and forth, over and over (alternating current--basically imagine there's a guy with a 120V battery moving the wire from the positive terminal to the negative terminal over and over, 60 times per second). This +120 and -120 averages to 120VAC (it's actually a little more complicated than that--there are a lot of in-between voltages, but close enough for illustrative purposes). The "hot leg" is either pushing electrons or pulling them. The change happens 60 times per second (hence, 60Hz), and is SUPPOSED to be a smooth sine-wave change from positive to negative values, and if you plugged your outlet into a preamp or an occilloscope, it should produce a 60Hz sine wave (before it burned out the preamp, anyway).

2. The wider prong is the the "neutral" leg. Under the NEC, the neutral wire is always white. It is connected, through the electrical panel, to ground (literally-- it connects to something like a cold water pipe or a stake in the ground). Under normal circumstances, if you have no load on the circuit, you should be able to stick your tounge in there and get no worse effect than a yucky taste. When you plug something into the outlet, the alternating current from the "hot leg" (which is carrying the above-referenced 120VAC) goes through the signal path of the device and returns to ground via the neutral leg. Basically a generator somewher out there is generating an alternating current that wants to even itself out by either pushing electrons into the earth, or sucking electrons out of the earth. Why does it want to do these things to mother earth? because she's the biggest thing around and she can handle it. She has so many electrons and protons that she can easily absorb or give up a few thousand here or there. Like a raging drunk who's looking to get laid, those electrons want to get neutral. If you get in the way, they'll go through you, but if you give them an easier path to the mother lode, they'll go there. And the neutral is their path back to ground.

3. The "ground pin" aka The "safety ground" aka just "the ground" either has green insulation or is just bare wire. It is a seperate connection to ground, through which, under normal circumstances, no current is ever meant to pass. It may be connected to a ground back at the main electrical panel, or it may be simply tied off to the (grounded) metal conduit through which the hot and neutral legs run. This third prong is meant to provide a direct path to ground, purely for the sake of safety. Let's say you have a reverb effects box. The hot leg goes to the primary power supply, which probably consists of one or more step-down transformers that convert the 120VAC to some smaller voltage like 12V or whatever, and passes through those transformers to the neutral leg path to ground. the whole thing is enclosed in a metal housing. What happens if there is a catastrophic fault within the box and one of the high-voltage wires comes loose and touches that metal housing?Something bad, that's what. UNLESS, of course, that metal housing has an easier path to ground than the person touching it. Which is where the ground wire comes into play. Typically, the ground wire is connected straight from the chassis (the metal housing) right to ground. Its sole purpose is to serve as a better path to mother earth than you are in the event of stray voltage, lighting strike, power surges, or mechanical failure within the electrical device. In audio equipment, it also often serves as the reference for the audio signal voltage, because it is SUPPOSED to be a direct to path to ground, and to contain no charge whatsoever.

So that's what those three prongs are for. Got it? good.

What happens in the real world is often that the several lines are not exactly perfect-- this plug over here might be on the same circuit as a high current-draw device (like a loud guitar amp), and that current draw might mean that that particular outlet is only delivering 112VAC, whereas this device over here, on a different feed from the breaker, has very little load on it (like maybe just an effects box) and it is still delivering 119VAC. Now let's pretend that that both of those devices (the high-powered amp on circuit 1 and the low-powered effects box on circuit 2) are both referencing their signal to the ground pin. The potential voltage of the amp is 112VAC away from ground, and the potential voltage of the effects box is 119VAC away from ground, which means that there is a 7 volt difference between the two signals which is alternating at 60 cycles per second, and we are going to hear some major hum. Specifically, we are going to hear the effect of having a 60Hz sine wave generator operating at 7volts plugged between the effects box and the amp. I'm skipping over a lot and oversimplifying things, but that's basically how it works.

How do we correct this? By making sure that all of our signals are referenced to the same reference (ground circuit), within each signal path (in the above example, by plugging the effects box into the same outlet as the guitar amp).

I can't tell if this is making sense anymore, but it's tough to condense this stuff into a forum post (even one as long and rambling as this).

To get back to the original point, "balanced power" would mean having two "hot legs" as opposed to one hot and one neutral. Each "hot" leg would be delivering 60V+/- difference from ground at any given time, with the opposite hot leg delivering the same voltage, opposite polarity (this is exactly how a "balanced" mic signal is different from an "unbalanced" guitar signal). +60 on one side and -60 on the other adds up to 120VAC, the same as having one 120VAC circuit referenced to a neutral. There is ZERO benefit to this if you are using gear that is signal-referenced to ground, and it could potentially make things worse if you are using gear that is signal-referenced to neutral.

The ways that noise gets into a signal are many and complex, and what I wrote above is only a crude approximation of how a small piece of it works. I'm not even sure what it's supposed to prove, but if anybody's still reading this, I hope you've got the idea that it's all relative to ground, and if you can keep your ground signals consistent, then power conditioning is pretty much irrelevant, problem-solving-wise. If you believe that it can make your tracks sound better, or if you cannot coordinate your paths to ground or prefer not to worry about it, then a power conditioner will do a pretty good job of making sure that you have consistent relative power voltages.

Cheers.

Larry, Fletcher touched on this subject a bit in his ProSoundWeb forum. It's an interesting read. Especially if you use surge protection power strips.

One thing that I don't think has been mentioned is power sags. My old studio partner has a Furman conditioner that indicates over and under voltage. More often than not, it registers under voltage. We live in a semi-rural part of North Carolina that is being built up quickly around an aging power grid. Seems to me that sags would be just as much a danger to equipment as surges.

Well, I already have a fair understanding of general purpose electronics (and how mics work and such). But I'm enjoying your writing style so much I don't mind You should write one of those "For Dummy's" books

Whatever else you care to write will be read by at least me. And I have a theory that there are lot's of "experts" out there who might benefit from this too.

ORIGINAL: krizrox

Interested to hear any stories about various power conditioning solutions you may have tried or are currently using. What works and what doesn't? A lot of it sounds like marketing hype to me personally.

I think for live work where the source may be un-relible they are a must. For studio use they are not needed in the DAW age. I use a UPS just so if the power goes out the PC doesn't crash but that's it. All my outboard gear is engineered well enough not to pick up noise or change spec (or sound) with power, as is my sound card. The PC has a switching power supply so it doesn't care. In the old days with dozens of AC powered boxes and a mile of wire connecting them you needed all the help you can get but the PC conponents are on the other side of the power supply so no problem there. I spent the money on a good power supply for my PC.

I have heard that balanced power is cool for guitar amps because you get less humm but I don't use amps anymore. I still think it would be cool to have a big balancing transformer for the entire studio for all the analog gear.

Hey yep would you be willing to please contact me directly? I would like to communicate with you off-line if that's possible.

lnlrecording @ ameritech dot net

thanks!

I can only talk about the ones I use - in San Jose the power on that grid was nasty, I've just moved to Santa Clara where it is cleaner. Regardless I still use this guy to regulate brown and surge conditions:
http://www.furmansound.com/products/pro/reg/reg1.php

This balanced power conditioner was an experiment:
http://www.furmansound.com/products/pro/blncd/balanced1.php

I did not do extensive testing before and after - I can say this, when I have all of my equipment on and I'm doing my audio thing there is never any noise that isn't music - no pops, clicks, hiss, hum, nothing - absolute silence. Some of this is due to the audio equipment for sure but I suspect some of it is due to the power conditioning. I don't need to tear it apart to find out since I have a pristine environment. At my old house a couple of months ago when the A/C kicked in the lights dimed - you guys know what this means, but I never heard any hiccup from my audio equipment. If one of these pieces goes down I will certainly replace it. Troubleshooting an existing problem with hum or clicks is a different situation that I have never been in since using this equipment...so this is kind of one of those things faith and folklore is built on, haha. I made a preventative strike - what can I say? Just trying to be honest here!

I said I would talk about ground impedance, and here's a VERY short version:

Impedance is a (relatively) difficult thing to measure. It is basically a combination of the overall resistance, capacitance, and reactivity of a circuit path, and it is frequency- and voltage-dependent.

Resistance is the measure of the degree to which a particular object or substance RESISTS the flow of electrons. Things like copper and gold have very low resistance and will happily pass along extra electrons (these are called "conductors"). Things like rubber and glass have a lot of resistance and don't like to trade electrons with anybody and will only do so when violently persuaded by severe electrical charge (these are called "insulators").

Capacitance is a measure of the degree to which a system will tend to STORE an electrical charge rather than pass it along. A capacitor can be thought of as something like a battery. A capacitor is different from a resistor, and works differently, because it is SAVING a charge rather than refusing it, but it can sometimes serve a related function because it has the effect of NOT passing along the electrons that are delivered to it.

Reactance is basically a phase-related type of resistance. It is a sort of "inertia," or a reluctance of the electrons to move, like a crowd that will eventually let everyone through, but slowly, at a speed related to the pressure of the incoming current.

Everything in the world, from a copper wire to a roll of toilet paper to Shania Twain has certain degrees of resistance, capcitance, and reactivity.

Impedance is basically a summary judgement of all of these factors, of which resistance is usually the biggest element. Impedance is a sort of rough measurement of the overall difficulty that a current of electrons will have in getting to the intended target, and is sometimes referred to as "complex resistance."

Generally speaking, the ground connection in your outlet should have close to zero resistance, for all practical intents and purposes. It should be a direct path to ground through a conductive material, like copper wire or steel conduit.

Under certain cirumstances, such as a ground connection that is surge-suppressed to protect against lighting strikes or whatever, the ground connection may have small but significant amounts of capacitance or reactivity that could potentially have an effect on the audio signal.

The good news is that this is pretty rare, and that it can STILL be solved by keeping your entire signal chain on the same ground. As long as the ground impedance is the SAME for all components in the signal chain, it still basically counts as zero.

So again we come back to the fact that 99% of building electrical problems (which are relatively rare to begin with) can be fixed by keeping your signal chains plugged into the same outlet (the fancy name for this practice is "star grounding" meaning all the ground circuits come back to the same path to ground).

Cheers.