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Positive Feedback ISSUE 4
december/january 2003


An interview with Martin Glasband of Equi=Tech
by Dave Clark



Dave: So how did you get into this business?

Martin: First of all, I started out as an electrician wiring garages. Then, I read the entire electrical codebook cover to cover and I graduated to houses. Then it was on to commercial businesses and recording studios. Some 20 years later, I was handling large electrical engineering projects and writing code in the NEC. I became fascinated by a narrow part of the electrical power industry that deals with power quality… i.e. that portion of the electrical engineering trade that is concerned with how power affects the performance of sensitive electronic equipment and electric motors. I came upon the balanced power solution when I was designing an electrical plan for a large recording studio project in Los Angeles in 1988. Needless to say, the project was highly successful. Soon thereafter, I found that I could produce these systems on a smaller scale with much the same results. That’s how Equi=Tech was born. I made a few balanced power systems that could just plug right into an AC outlet and run an entire recording rig. The results were amazing. Now we routinely build and engineer systems that range in size between 5 amps and 5,000 amps.

Dave: What do see you as being the biggest problem with AC?

Martin: The biggest problem I see with AC power today lays mainly in the way modern electronics and lighting equipment affect the quality of power in an entire grid. They create a lot of distortion and noise. Residential areas are by far the worst because utilities are not regulated the same way as they are in commercial areas though both share basically the same problems. These problems are brought about by capacitive or reactive loads, such as switching power supplies in computers and even now in TV sets. Fluorescent lighting and other ballast operated lighting systems are equally detrimental to power quality. When everyone is contributing to the problem, no one has it good anymore.

There has never been a definitive solution for this problem until balanced power came along. Traditionally, active filtering and some sort of power regeneration was the only answer prior to the arrival of balanced AC. But even those approaches prove to be quite lacking in effectiveness when one switches on the components. Harmonic currents are ruining utility power. They are very harmful to components and they are also very difficult to remove without either balanced AC or a regeneration/active filtering system of some sort. But even at that, balanced AC is the only method that is "self-cleaning" when equipment is turned on and it is far more efficient.

Traditional AC systems that are unbalanced provide for the appearance of a lot of local distortion in AC circuits, which is to say that AC power is designed wrongly for the loads that are placed on it. It could even be said that local power disturbances have more detrimental an effect than utility power distortion does on audio system performance. Component power supplies themselves cause significant problems within an interconnected series of audio components. That’s just the nature of the beast. I don’t want this problem overlooked because it too is huge.

So the biggest problems are two-fold. One part of the problem is what you are fed from a utility power grid. The other problem is the AC noise that’s locally generated within the audio system itself. The first one is commonly accepted and understood. The second one, up to very recently, no one has cared to discuss.

Dave: There seems to be as many different approaches to "fixing" AC as there are to cold remedies. Is it more a matter of this problem is more important that that? Or are all these different products out to fix the same problem?

Martin: Yes, power quality is definitely a multi-headed beast. Fortunately those heads are numbered. Let me see if I can list them all. There is voltage regulation, harmonic distortion, harmonic or reactive currents, nuisance grounding currents, power factor, voltage transients, current and voltage sag. Hey, I guess there really aren’t that many of them. So let me put them in order of significance, as my experience with these different issues would dictate.

1. Power factor. That is something that indicates the degree that current and voltage are in phase to each other. All impedance loads affect power factor. That includes just about everything except toasters, heaters and incandescent light bulbs. When current and voltage are out of phase to each other, to that degree, nothing happens at all. Electricity requires both current and voltage present for anything to happen. You can have 120 volts coming out of your wall sockets but your computers won’t even boot up in a worst-case scenario, because if there are too many reactive loads on the system, voltage will drastically lag the current phase and nothing will happen. It’s very strange when that happens but understandable to a power quality guy. In the audio realm, when power factor is low, audio equipment sounds starved for power, flat, compressed and weak. This is because to a degree, voltage and current are not present at the same time. To a degree, there is no power.

2. Harmonic distortion. You can also throw harmonic and reactive currents into that category too. These are often referred to as "eddy currents" on electrical lines. "Trash" is another expression that refers to power harmonics. Interestingly though, AC harmonics are inversely proportional to power factor. They are all related. Simply stated, the more trash on your AC line, the less "active" power you will have. As active power is expressed by the term kVA (kilovolt amperes), reactive power (the bad stuff) is referred to as kVAR (kilovolt amperes reactive). Wouldn’t it be nice to just eliminate reactive power? That’s the beauty of balanced AC. It causes all that reactive power to fold up on itself and go away. What’s left is active power… current and voltage both in phase to one another -- real electricity, high power factor. Better sound.

3. Nuisance grounding currents. The problem with traditional AC topology is the fact that there is a neutral (grounded) circuit conductor. All junk on the AC neutral line is connected to ground at the main service where the neutral is grounded to the AC system ground. This ground is also unfortunately part of your audio system’s signal reference, which unfortunately means that reactive current originating on the neutral line will flow through the ground into your equipment’s signal circuits. If you attempt to separate audio and AC ground by lifting the AC ground away from the audio ground, you are flirting with danger as well as setting up a ground loop scenario by having two different grounding potentials. Two-pronged AC power supplies attempt to avoid the issue entirely but in so doing, they risk an increase in RFI. Without a low impedance ground, the audio/video cable shields are rendered less effective or even useless. It becomes a matter of choosing the lesser of two evils. We can’t have that. The fact that balanced AC completely nulls out nuisance grounding currents offers another solution. This is perhaps its most notable advantage. You can ground everything for maximum shield effectiveness and have no grounding currents left running around to pollute audio signals. Grounds are totally noise free and so are the internal audio circuits. Once again, better sound.

4. Current sag. This is a different sort of beast. Though related to low power factor in the way it affects performance of audio and other sensitive electronics, it is still a different problem worthy of some attention on its own merits. Here you have to look at how current is handled by the AC system itself. Small wires or an overloaded utility transformer affect current delivery. The impedance of the AC source is another factor that affects current delivery. When a big power supply in a power amplifier says give me power now, it doesn’t mean OK… I can wait a few milliseconds. NO. It demands the current immediately so its power supply capacitors can be charged and ready to deliver power for the next thump of the bass drum in real time… not sometime later. When your amplifier seems to lack authority and your music sounds compressed and weak and the bass just booms and sounds undefined, it’s probably because your amplifier’s power supply is starved for current. Originally this was the Achilles heel of our balanced power systems. But for the last few years, we have been producing a very non-restrictive type of system that delivers current very quickly on demand. I’ll get more into that a little later.

5. Voltage transients. AKA spikes. Primarily, inductive loads on the power grid cause these to occur. A noisy elevator motor, a worn out air conditioner compressor, a refrigerator that recycles etc. etc. are examples of where transient voltages originate. They routinely show up as pops and clicks in audio. Sometimes large inductors and large inductive loads can release an inordinate amount of voltage on the AC line and these are the equipment killers we fear. Though I do rate this phenomenon as dangerous, I rate it downscale here because this technology is old hat and it’s relatively cheap. MOVs, cascading diodes and some newer faster semi-conductor devices are capable of clamping down on these spikes at relatively little expense. But one very overlooked fact is how well isolation transformers with grounded Faraday shields protect from voltage spikes. Imagine a grounded copper barrier that lies between the input and output coils of a transformer’s windings. What could possibly get through that into your equipment? You’d rather not know. Just remember, don’t talk on a landline phone’s handset during a lightning storm and you’ll live to hear more music.

6. Voltage sags and rises. I’m sure there are those who’s interests lie in this area of power equipment would argue my placing voltage regulation at the bottom of the list. However I think I’m right. Let me explain. If Sony built a TV set, for example, that needed a steady voltage, say 120 Volts, how could they possibly sell TVs to someone in Phoenix where the voltage is usually right on the money and also to someone in New York where sags to 110 Volts are commonplace? They can do it because they build their power supplies with built-in regulation. So does everyone else. Problems arise only when the supply voltage exceeds or falls below the range within which the equipment was designed to operate. It’s nothing for voltage to drift one or two volts (1% to 2%) during a listening session, but the regulation in the power supplies can easily handle that. So what’s the big deal? Well that’s probably best answered on a case per case basis. Don’t get me wrong. I’m not suggesting that voltage regulation is useless. But I do think it’s oversold and overstated in its importance. If you have a local problem with utility voltage, you may have some success with the utility to correct the problem. They do have tariffs to abide by. But if you have a voltage problem, and you don’t want to trust your utility company to fix it, then by all means do something about it yourself. That’s our approach to the issue at Equi=Tech. Roadies that do concerts are probably our most needy customers where voltage regulation is a genuine issue. Just for your information, the NEMA "A" range classification for power supply voltage, which is the most common type, has approximately an 8% tolerance from 120 Volts nominal. But if you think your equipment is more finicky, try voltage regulation. It’s your money.

Dave: Is it an issue of poor design in power supplies or just the nature of AC?

Martin: We have seen some real winners in the power supply department, but it’s mostly an issue of poorly designed AC. Electrical engineers at the beginning of the 20th century had other things on their minds besides reactive currents and power factor. But the problem is that we are still stuck with the same power architecture 100 years later. The idea of using a common (neutral) conductor in AC wiring has been around for a very long time. That’s the issue. When we started using impedance loads on AC grids, problems began to popup that became more and more of an issue to deal with. Triple that concern when reactive loads such as fluorescent lights and DC power supplies became commonplace. Had we the same concerns when Westinghouse and Tesla wired up Chicago with AC power over 90 years ago, we would probably be using balanced AC instead of the unbalanced version we have all grown accustomed to.

Dave: How does your product address this? Is there anything else going on inside your stuff that we can discuss? Any "black-boxes inside?"

Martin: Not really. Balanced power is very simple to understand. However as we like to say at Equi=Tech, "Not all Balanced Power is Equal." You can take that literally or in a figurative sense. Both interpretations are valid. I’ll get more into this in the next question.

Dave: What advantages do your products have over the competition?

Martin: First of all, everything we make has been designed by me personally and am I ever a stickler for detail! We don’t use quick connects in any way. Every termination is made under a flat screw-head and all terminals are the Amphenol-type pressure connectors were 20,000 psi practically fuses the copper terminal to the copper wire. To that we heat shrink everything to let no air in. From my many years of experience wiring up control panels and numerous other electrical paraphernalia, the most common of all reasons for failure are due primarily to heat damage from poor or substandard terminations. We build our systems for the long haul. Their failure rate is incredibly low, certainly under 1% but probably much lower than that.

Let me also expound a little bit on the previous question where I mentioned that not all balanced power is equal. At what point do you consider something to be truly balanced? Within 1 volt? Within 1 milivolt? How exacting should that specification be? Balanced power is when you take a normal 120-volt line with a neutral and a hot wire and balance the 120 Volts instead. That gives you 60 Volts-to-ground on both sides of the circuit to ground. In a perfect system, everything would be perfectly phased. In other words, you would have exactly +60 volts on one side at the same instant you had exactly -60 Volts on the other side of the line. We demand as close a phase match as possible because this is how balanced power nulls out noise. It’s called common mode rejection. Any variation away from that perfect balance point will leave some residual noise on the line.

While it’s true that any balanced power is better than no balanced power, the more precisely the power is balanced, the wider the bandwidth of noise attenuation there will be. We use a patented bifilar winding method when we design and build our transformers. In other words, both halves of the output winding on our transformers are applied side by side in one pass wound with 60 volts worth of turns. We then connect the two parallel-applied coils together in series. In other words, we connect the end of "wire A" to the beginning of "wire B" and call that the "center tap" or grounding reference. Voila, you now have a near perfect balance across the output of the system and a very wide bandwidth of noise attenuation as a result. Though this winding method is not new per se, it’s application to a balanced 120-volt transformer for application to an AC load is. Why would it have ever been used in a balanced power system or even considered without balanced AC in the first place? Lucky me. I have a patent on this apparatus.

Let me also add that we have been building these systems since 1989 and no one even comes close to that in experience. So it’s not just our demanding manufacturing specifications and a little innovation that makes our products better, it’s a whole lot of experience that goes along with it. We have spent the better part of the last 10 years refining our components and products so they perform better. That shows.

Dave: I have heard people running 220 into their house and then going into a transformer to convert this back to 110, thereby eliminating common mode noise. Is this the same or just a different approach?

Martin: It’s partially the same. But unless you have a center-tapped transformer that outputs 60 Volts-to-ground and 120 Volts line-to-line, you are missing the boat almost completely. What many people fail to understand is that most all of the objectionable AC artifacts that affect their sound system are produced by the very power supplies they flip on when they listen to music. That’s on the load side of your step-down isolation transformer and has little to do with what the utility company gives you. Balanced power effectively deals with this phenomenon like no other AC system.

I also think this would be a good place to mention the 240-volt components that are preferred by some. Most people know that 240 volts is what is present in most households and it is essentially balanced. Well, this is a good thing to a point. Just remember that this utility transformer is not very accurate and you are also loading it up disproportionately in an irregular manner with 120-volt appliances and lights etc. That messes up the balanced source even further. You could do better than that for your audio investment. Good isolation transformers are an excellent addition to any power system that runs sensitive electronics, but when it’s done right, the results will surely astound you.

Dave: Are there any potential drawbacks to using an approach such as yours?

Martin: Let me approach this question with some tact and reservation. Essentially the answer is no, however I’ve seen some rather unexpected things happen on rare occasions. Probably the most common of them is when an older piece of equipment that has been running on "shore power" for many years is then plugged into a balanced power source. There have been some occasions where the noise levels have actually increased rather than lessened. What we’ve found to be the most common cause is lack of maintenance in these situations. Frequently, power supply caps are changed out in professional recording studios as a matter of routine maintenance and here the problem is the same. Neutral-side capacitors in power supplies and RFI filters are continuously being hit with reactive currents, which cause some deterioration in many of cases over time. This may not be noticeable when using "shore power" because there is no voltage on the neutral wire. However, when balanced power is applied to the same power supply, all of a sudden there is 60 Volts there where formerly there was none. This may cause leakage current to flow because of the 60-volt potential across the leaky cap. The solution of course is to have the power supply serviced. It’s as routine as changing an oil filter on a car. Also, there are some very old radios from the early 50s and before that have a neutral-grounded chassis. That will not do. The breaker in the balanced power system will trip. This is the only case of incompatibility I have ever seen.

Dave: Where are your products best used - sources (digital), electronics (preamps and/or amps)?

Martin: In every case, the benefits to source electronics benefits are quite apparent. The more accurately balanced the power source, the better it works as even greater detail is recovered in the noise floor. There is a clear reason for this. Source electronics including preamps have the greatest amount of gain. Often miniscule audio signals are highly amplified and balanced power eliminates noise at this stage where it’s most critical. The line level output from these components sees the same relative background noise levels as the input side but the line level signal is proportionately much greater than the noise at this stage so there is less harm done to the audio signal’s integrity. High gain and high impedance equipment do benefit more than amplifier loads in this way.

But, I would be remiss not to include amplifier loads as another component to benefit from balance AC. Their power supplies are normally an even greater contributor to the background noise levels than any other piece of equipment because their power supplies are much larger. Remember that all of these components are interconnected through grounded cables so in effect, they all share the same noise sources. So when you reduce noise everywhere you can, all components benefit. There are some arguments that suggest that separate power sources are optimal, however this idea was conceived without the benefit of balanced AC. Balanced power effectively nulls out all of this junk so what’s left to isolate? Man, we are really splitting hairs here. The difference between isolating each and every power supply and not doing that in a balanced AC system is miniscule.

There are other issues involved with powering up amplifier loads. Those mainly involve current delivery. Here is where we are also very proud of our accomplishments. The Model "Q" product line we build is specifically designed to handle current demands from monster amplifier loads. Model Q systems are basically built around a VERY low impedance transformer. And, like all transformers, they represent a current reservoir similar to the way capacitors retain and maintain voltage. All that was ever missing in our original models was a low impedance transformer design. There is a marked sense of increased power where a Q is used with an amplifier. Effortless is the word that best describes it. Along with this, there is a marked increase in bass definition and in some instances an extra octave of bass becomes audible. We are thrilled to hear this from our customers, as it’s definitely something new and exciting for everyone who experiences it. I realize that the concept of applying any sort of power conditioning device to amplifiers has been frowned upon in the past, but this is typical of the landscape laid out by those who have come before us. We have been breaking new ground for many years. Now it’s only a matter of time before people find out that this myth is just that, a myth built on old technology.

To sum it all up, there are many users prefer two systems, one for the source electronics and one for the amplifiers. But in my humble opinion, it’s a case of diminishing returns. The difference in audio quality between using one Model Q system for all components, and separate systems for source components and amplifiers is not much. However many customers have chosen the multi-system route to get the most they possibly can out of their sound system.

Dave: Where do see your company in the future? That is, what is on the horizon?

Martin: From the very beginning, I realized that revolutionizing AC power would be an uphill battle. You just don’t go out there and tell everybody that what they are doing is wrong and expect them to follow you even if you really did discover the "holy grail" in power technology. People by in large just take power for granted. That’s probably the biggest obstacle of all. Nevertheless, balanced AC is as scientifically sound an engineering concept as there could possibly be and that makes it an easy sell to someone who is educated.

My first battle was won in the NEC technical code committee meetings back in 1993 and we have been gaining momentum ever since. I recall being awakened by a phone call early one morning in January 1994 from the Vice President of a large well-known movie studio. He called me just to congratulate me on the success of my proposal for the upcoming 1996 National Electrical Code. He informed me that it passed the technical committee vote by a resounding margin. He also praised me for coming up with such a brilliant, simple and elegant solution to the many power issues that were confounding the engineering community. That was a very good day for me.

The latest edition of the 2002 NEC has moved the original article 530 Part "G" (1996 & 1999 eds.) to it’s own article 647, which in essence takes the lid off of balanced AC. No longer just approved for audio/video related uses, it is now regarded as an acceptable wiring method for any sensitive electronic component or facility. The new code even includes a section on balanced power for noisy lighting systems. Balanced AC eliminates power anomalies almost completely. Because it deals so effectively with power factor, utility companies have shown a great interest in this technology. More efficient use of power benefits everyone, not just the one end user. The potential savings in fuel and maintenance costs to a utility company are immeasurable. Balanced AC is also very environmentally friendly. Maybe one day we will see rebates and other forms of incentives from utility companies for end users of balanced power. But don’t hold your breath. The wheels of heavy industry are apt to turn very slowly at times where new standards and practices are involved. It takes a long time to educate the masses. Studies will be needed. But that day will come.

I hardly know where to begin to describe the future of balanced power. First of all, everyone who is anyone in pro audio is using our equipment. The rest of them are in line for it. The military also has its power problems like everyone else does. Noise problems in onboard guidance systems in fighter aircraft, limitations and failures in communications and data processing systems, submarines and other naval vessels -- the list goes on and on. Large pharmaceutical companies have demonstrated interest in balanced AC for use with their coulter counters and cell separators used in drug manufacturing. The FAA has shown an interest in balanced power for their ASR-8 flight control radar system. NASA is presently using our balanced AC systems at JPL in Pasadena. The National Science Foundation is also using our systems with their telescopes at the Gemini Observatory in Hawaii. As a power quality applications engineer, it has been an educational experience for me to say the least.

So far, we have barely scratched the surface. Many more companies in the high tech sector like Intel for example are fanatical about power quality. The potential for catastrophic losses in their automated manufacturing plants is unimaginable. For that matter, ISP farms are often besieged with power problems too. Even the phone company! From the very beginning, Equi=Tech has pioneered the development of balanced AC in more and more areas of technology and it is my intention to see it all the way through until it has achieved its rightful place as standard practice. We are constantly making new inroads. It’s only a matter of time. Show me someone not using balanced power and I’ll show you someone who should be. The benefits are great and the technology is bombproof. Balanced power belongs wherever there is an impedance load on AC. That about sums it up.

Dave: Thanks Martin!