Friday, October 3, 2014

Preserving High-end History - Part 3

Passion in the restoration field is a common theme among the member elite; some get hooked early in life while others eventually migrate into the field. The first person of interest in this series is "Sonny" Clutter, someone possessed with early radio restorations. Note that in the high-end, I believe that being possessed is a positive trait although my wife may kindheartedly disagree.

C. E. "Sonny" Clutter
Sonny became interested in radios at the impressionable age of 10. His stepfather was what you would call a "picker", he would buy and sell anything and everything he could get cheap, and the two started traveling together at about age 12. They frequented local appliance dealers (who took trade-ins back then) and would often buy a whole truck load of stuff. Sonny can remember seeing 7”, 10”, and 12" TVs stacked high in the back rooms of these dealers all ripe for the taking. These trade-in TVs fetched about $5 each in those days, even less if you bought them by the truck load. Depending upon condition, I either removed what was of value and scrapped the rest, or re-sold the better stuff at auction houses or local buyers.

Sonny Clutter

Sonny’s first restoration project was a 1949 10" Meck television way back in 1953. One unsuspecting day Sonny’s stepfather gave it to him to tinker with, what a thrill that was for a young and innocent child. With a little loving guidance, Sonny was able to make it work and that became their family’s first television.

Sonny remembers the old console radios they would get, especially the large Majestics. He marveled at the intricacy of the various parts, circuitry, and the sealed containers. His curiosity overcoming him, Sonny would remove and open the beautiful constructed aluminum and sometimes copper cans containing the meticulously-wound coils on these old pieces of engineering and marveled at how these made sounds and music. What a thrill that was for him to bring one of these old relics back to life by his own hands.
Not satisfied with a casual understanding of electronics, Sonny found an old NRI (National Radio Institute) home study course in 1954 and taught himself the basics of radios and electronics.

In 1956 Sonny took an after school and week-end job at a local Radio & TV repair shop in Ashland (Supreme Radio & TV). Owner Jake Rodman couldn't afford to pay Sonny a salary, so he started working for nothing (a "gopher at first) just for the opportunity to learn more about the technology he loved. Jake, a first-class service technician in his own right, taught Sonny many of the things that he still practices to this day. Sonny started by working in Jake’s shop doing odd jobs, sweeping the floor, and later was trusted to test tubes for customers at the counter. He also spent time on the work-bench asking Jake numerous questions and learning specific trouble-shooting techniques. It wasn’t long before Sonny joined Jake on service calls and antenna installations, and after only a few short weeks Sonny started earning a modest salary. Getting paid to do what he loved seemed like the best job he could ever have.

In 1959, Sonny joined the Air Force where he again studied electronics focusing on radio communications. After the USAF he worked as a consumer electronics service technician but could not shake his fascination with old technology. In 1962 his love for old radios was rekindled when he accidentally crossed paths with an old 1927 "Kolster" AC radio. He meticulously cleaned and re-finishing the cabinet and found that restoration was still in his blood. In 1996 he devoted himself to his “hobby” and has since turned this passion into a thriving Internet business.

Sonny’s Immaculate Workbench


Since 1966, Sonny dedicates his time to restoring all sorts of old radios and televisions and has many of these for sale on his website. Sonny is not interested in upgrades or modifications but rather in restoring a piece of equipment to its original design, just as you would have purchased it brand new way back when.

In the next interview, I will again add a name to the "possessed" list with a local Tampa person with an unusual story. Until then, remember to listen with your ears and not your eyes.

Yours for higher fidelity,
Philip Rastocny

Skeptics are essential to keep us sane; skeptics do little to keep us inspired. Philip Rastocny, 7-16-2014

I do not use ads in this blog to help support my efforts. If you like what you are reading, tell your friends and please remember to reciprocate by purchasing some of my highly affordable works at Amazon.com. My titles include:

Sunday, September 28, 2014

Preserving High-end History - Part 2

In this series, I will interview a core group of dedicated technicians and engineers who do the same thing: restore antique gearThe common theme among these restorers is their early-life fanaticism, attraction, or addiction - none of these words truly come close to describing the intense love or passion behind the joy of bringing something old back to life. There is a moment in their lives where everything changes, a tug or pull that draws them into the fold and the mystery behind the glowing tubes and colorful parts captures their attention. This deep love and fascination steers their life's direction underlying almost everything they choose, even where they live and definitely their vocation.

Antique restoration of any form follows this same pattern. Think of restored cars, art, instruments, toys, all of those folks who choose to do so do it for more than the money. What it takes sometimes to complete the restoration cannot come close to breaking even but yet they do it anyway if there is uniqueness or just desire behind that articular effort. There seems to be a little voice inside that says, "I can make this work again..." that drives them all to do what they love.

While my main theme in this blog is high-end audio, I am temporarily expanding the theme in this series to include a few of these other dedicated individuals who restore other types of electronic treasures like radios and televisions. This same passion flows through their veins with such intensity that when meeting them you are immediately struck with their sincerity and expertise. All look at their work as preserving history and reviving what the inventor, engineer, or crafts person created. What attracts their attention is uniqueness, something they had not tried before and wanted to learn more about that particular thing that made it unique.

Audio engineers created novel solutions to the plethora of audio problems and many did so in an aesthetically pleasing manner to appeal to those who consider high-end gear ugly toys. Bang and Olufson (B&O), a company considered to produce good but not necessarily high-end gear, has at  least taken the concept of attractive designs to its own high-end extreme earning collection status in New York's prestigious Museum of Modern Art.

For example, in the era of linear-tracking tonearms, the B&O Beogram 4000 turntable took what most manufacturers constructed as a mechanical masterpiece but a visual disaster and transformed it into a small piece of functional art. B&O carried a design theme across individual pieces so an entire system looked uniform, a continuation of an idea rather than a standout or afterthought. And it is for this reason I give B&O gear a nod for a less-than-optimum acoustic but top-of-the-line aesthetic system.

The B&O Beogram 4000 circa 1972
But I digress as usual and I must refocus on what this series will cover. To begin, here is a brief reminder of how this all came to be. Let's pause and recall the contributions of the inventors who developed the technologies we take for granted.

How It All Started
As mentioned in numerous posts in this blog, home audio entertainment began in 1877 with Edison's first cylinder player, a mechanical amplifier that took tiny vibrations recorded on a cylinder and using the horn-loading (i.e., impedance-matching) principle transformed whispers in the groove into roars from the horn. Electronics slowly evolved at this time with a basic discovery that electricity could move without a wire through a flame. From that knowledge, a man named Lee De Forest looked at this phenomenon a little differently and created a flame that did not extinguish, literally a glowing wire inside of a vacuum (aka a vacuum tube). From this approach he created the first electronic audio amplifier in 1906, a headphone amplifier for a radio receiver called the Audion.

The first prototype Audion with the grid (zigzag wires) between the filament and plate circa 1906
What intrigues me about Lee is his atypical approach to solving a problem. He looked at the issue from a different perspective than everyone else and came up with a solution that literally revolutionized everything. This radical idea started an industry making everything we know as electronic today possible, from radio communications, telephony, home audio, rock concerts, iPods, to computers and digital music, and anything else you can think of. It is this same interest in solving problems by looking at them from a different angle than everyone else that drives the high-end still to this day. We owe it all to Lee De Forest.

Refinements continued by many others to this first crude device made possible every electron tube ever conceived from the 12AX7 to the 5U4 to the KT88. And with the invention of the transistor on December 23, 1947 by the combined efforts of three Bell Telephone Laboratories Engineers, John Bardeen, William Shockley, and Walter Brattain, the history of amplification was again going to take a monumental turn.

The First Prototype Transistor circa 1947
And yet there was still another turn in the industry: the tiny integrated circuit. Here, thousands upon thousands of transistors could be packed into a small space giving engineers building blocks from which designs could be simplified. Two separate engineers, Jack Kilby  of Texas Instruments and Robert Noyce of Fairchild Semiconductor, invented essentially identical devices (integrated circuits or ICs) and both were granted patents for their efforts. The difference was that Kilby used germanium (US Patent #3,138,743) and Noyce used silicon (US Patent #2,981,877) for the semiconductor material. Despite ensuing legal battles, the two wisely decided to cease litigation and cross-license their technologies. This solution gave birth to an industry that made miniaturization possible, one that we take for granted today.

Two separate engineers, Jack Kilby  of Texas Instruments and Robert Noyce of Fairchild Semiconductor, invented essentially identical devices (integrated circuits or ICs) and both were granted patents for their efforts. The main difference was that Noyce used silicon (granted US Patent #2,981,877 in 1961) and Kilby used germanium (granted US Patent #3,138,743 in 1964) for the semiconductor materials. Despite ensuing legal battles, the two wisely decided to cease litigation, join efforts, and cross-license their technologies. This compromise gave birth to an industry that made electronic miniaturization possible, one that we take for granted today.

First Prototype Integrated Circuit of Jack Kilby circa 1958
The stage is now set for the active components used in all technologies for the manufacture of any electronic device. Combined with other passive components such as wires, transformers, resistors, capacitors, and inductors, and the previous invention of the printed circuit board by Paul Eisler in 1936, mass-produced electronics took off in the late 1960s. Because of this and other advances in manufacturing techniques, the cost of electronics of any kind tumbled making once hand-built esoteric things easily affordable.

It is the same type of history behind the product that restoration technicians and engineers value. What some people see as an antiquated piece of tinny-sounding junk these people view as high prized works of art. In Part 3, you will meet the first of these restoration experts and be introduced to their way of thinking. This series is not dedicated to old electronics or the advancement of the high-end as much as it is the people who care for these relics and the stories behind their passion.

If you wish to contact me for a restoration or upgrade, you can email me at
philip at okstatealumni dot org
I cannot guarantee I will respond quickly but I eventually get to all of my messages. Until next time, keep listening with your ears and not your eyes.

Yours for higher fidelity,
Philip Rastocny

Skeptics are essential to keep us sane; skeptics do little to keep us inspired. Philip Rastocny, 7-16-2014

I do not use ads in this blog to help support my efforts. If you like what you are reading, tell your friends and please remember to reciprocate by purchasing some of my highly affordable works at Amazon.com. My titles include:

Wednesday, September 24, 2014

Preserving High-end History - Part 1

This morning, a friend sent me a link to a TEAC TS-85 magnetic levitation turntable, one that used large circular magnets at the center of the platter arranged in repulsion to "float" the platter on an invisible magnetic field (no thrust bearing required). This was a great idea but its drawback was that it attracted metal and other magnets that came near them, such as the things phonograph cartridges and tonearms are made.

The Innovative TEAC TS-85 Magnetic Levitation Turntable circa 1972
Another attempt to eliminate thrust bearing noise was the air-bearing approach by Makato Ikeda where the platter was floated on a thin cushion of air supplied from a tiny, very quiet air compressor.

The Fabulous Micro Seiki SX-111 Air Bearing Turntable circa 1982
Not only did engineers create novel solutions to audio problems, they did so in an aesthetically pleasing manner to appeal to those who consider high-end gear ugly toys. Blending style with design at least improves the chances of such a highly-desirable piece of gear making it past your live-in censor and into your listening room (yes, the dreaded spousal-approval-factor rears its head for anything that appears in a home in most relationships).

This got me thinking about the many other types of innovations in audio design that have come and gone over the decades since Edison's first cylinder, not just these unique approaches to eliminate a problem with turntable noises. Ah, the price of progress... And then I thought of how the designers and technicians who developed and maintained them are now either deceased or retired and how - if we are not careful - their novel ideas and innovative approaches to advancing the state-of-the-art could be lost, a thought that made me a bit melancholy seeing myself included as one of those same people.
The Edison 1877 Phonograph
For example, if it weren't for musicians and high-end audiophiles insisting that the sound of tube audio gear was superior to that of transistors, all equipment today would be solid state (I shudder at the thought). If people back in the 1980s did not listen to the music played back through CD players, all music today would be digitally mastered and streamed.

A friend recently asked me to restore his Audio Research SP11 preamp, undoubtedly one of the finest pieces of tube electronics ever manufactured. I felt honored to attempt this restoration knowing that parts could be difficult to find (an issue with restoring any old technology independent of the audio category). I was correct when trying to source the gain and volume potentiometers having to source them from a specialty shop in Japan. Other parts were still obtainable and even better than those used in the original design. It took six weeks and parts coming from three continents to get this classic piece of gear working again.

The Listening Test of the Restored ARC SP11
Like restoring a classic car in one of those reality TV shows, it takes a lot of time to do things right and a lot of love to coax a fine piece of audio gear back to life, or upgrade it to even beyond what the original designer had in mind. There are a few of us out there who take the time to tackle such audio restorations and in the next part I will introduce you to another one of them. Until then, think about what favorite piece of gear you have gathering dust in your basement, closet, or attic and seriously consider bringing it back to life.

In Part 2 of this series, I will discuss the origins and evolution of the technologies that made what we take for granted possible.

If you wish to contact me for a restoration or upgrade, you can email me at
philip at okstatealumni dot org
I cannot guarantee I will respond quickly but I eventually get to all of my messages. Until next time, keep listening with your ears and not your eyes.

Yours for higher fidelity,
Philip Rastocny

Skeptics are essential to keep us sane; skeptics do little to keep us inspired. Philip Rastocny, 7-16-2014

I do not use ads in this blog to help support my efforts. If you like what you are reading, tell your friends and please remember to reciprocate by purchasing some of my highly affordable works at Amazon.com. My titles include:

Monday, September 22, 2014

An Easy OPPO BDP-105 Modification

I have owned an OPPO BDP-105 for over a year now and have appreciated its fine quality especially when it came to NOT sounding like the typical digital music player. Right out of the box its strengths lie in excellent resolution and inner detailing heard only in the finest of the dedicated DACs available at the time. But one day, I was over at a friend's house listening to his Bel Canto DAC and quickly realized the shortcomings of the OPPO's Sabre 32 DACS. The Bel Canto was extremely silky with a level of sophistication that sounded more realistic, especially in the pianos we were listening to through his Martin Logan speakers (yes, the big ones).

This experience got me thinking: Phil, you haven't tried modifying your OPPO yet and the warranty is not behind you. WHAT ARE YOU WAITING FOR? 

With a quick perusal of the net for off-the-shelf modifications, people providing these mods described their changes and their results. Some focused on the analog output section (which I agree does need some work) and others on clock jitter (again, no argument here). But I'm the sort of dude who likes to get the most bang fro the buck and so I focused on two things: ground loops and the power supply.

The OPPO designers used an old-school approach to grounding whose philosophy goes something like this: Since the chassis is grounded, and since you need to attach a ground at every circuit board, use the chassis as a wire instead of running another wire back to the power supply. Such a philosophy saves a few pennies and imposes huge, clearly-audible problems. But further investigation of the grounding scheme proved to be futile since not only did the BDP-105 use screw connections to the chassis for PC board grounds, it used multiple ground traces everywhere on the PC Board adding what appeared to approach an infinite number of them.

The only solution for a design of this type (a non point-to-point design) is to cut traces on the board (as I did in my Dared MC-7P mods) and since I did not want to take the time to analyze what needed to be cut and what needed to be saved, I chose to only move the ground wire from the incoming power cord to the PC board screw closest to it. One problem down but I did not anticipate that doing this would yield huge sonic benefits. On to the next stage of mods.

In my web search, one of the things I found many of the folks doing is to change out the power supply diodes on the analog board to a fast-recovery and low-reverse-leakage-current (FRED) type. Frankly, I have never experimented with such diodes even though a friend of mine swore by them. So with a quick search at mouser.com, I found a few that seemed like they would do just fine. The only issue was that they are tens of amperes in capacity as opposed to the tiny one ampere capacity diodes currently used. No matter, in this case, the 10-amp capacity TO-220-2 case did not impose a physical real-estate related problem despite the fact that eight diodes needed to be replaced (D19, D18, D10, D12, D16, D17, D15, and D14). Everything fit nicely by using the leads from the old diodes to which I soldered the legs of the new ones.


OPPO BDP-105 PS Diodes

Now comes the acid test: how does it sound? Well, let me say this to give it all away: you gotta do this mod! I have always thought that the OPPO had a huge hidden potential and from my modding experience I suspected that it was an issue in the analog output stage (most likely the op amps and the output capacitor). But what these diodes do to clean up the background noise and permit the existing circuitry to operate more effectively is in a word JAW-DROPPING (OK, two words).

Everything, and I do mean everything, is literally better. Inner detailing, noise floor, sound stage size, transient response, tonal balance, strain, anything you can think of in the way of assigning an adjective to a flaw is seriously reduced. While more could be done to make this unit sound better, IMHO this is truly the single most cost-effective thing you can do to bump up the quality of the sound. I know that these diodes cost 10x more than the ones currently used (6 cents vs. 60 cents or less than $4 total) but the benefits are huge.

Sibilance issues I originally suspected where in the crossover network were in fact issues with the power supply in this audio section. Issues with time alignment (acoustic phasing) in the loudspeakers were actually issues with the power supply. And with the addition of the new Teflon bypass capacitors to the tweeter and super tweeter signal-path capacitors in my crossover network, I have never been more blissfully happy listening to music than I am now - and that is saying a lot since it is so hard to impress me!

Now I am looking with this same level of serious suspicion at the diodes in my power amp, preamp, and the phono pre-preamp. I can only imagine what blissful benefits can be achieved by simply swapping these diodes out too.

If you want me to perform this mod on your OPPO, email me at
philip at okstatealumni dot org

Yours for higher fidelity,
Philip Rastocny

Skeptics are essential to keep us sane; skeptics do little to keep us inspired. Philip Rastocny, 7-16-2014

I do not use ads in this blog to help support my efforts. If you like what you are reading, tell your friends and please remember to reciprocate by purchasing some of my highly affordable works at Amazon.com. My titles include:

Sunday, September 21, 2014

Capacitors: All Things are NOT Created Equal - Part 5

Manufacturing a quality capacitor is more difficult than one initially suspects, especially if low cost is your primary goal in the hopes of selling a bajillion of them. After all, if you can't sell a bajillion for peanuts, why bother? Everyone must eat and to do so profits must be made.

My favorite Woody Allen movie is "Midnight in Paris"  where Gill, a struggling screen writer, is engaged to marry his girl friend. His mother-in-law to be has a saying that applies to the issues of this lowly search for profits; she "always says cheap is cheap." Indeed it is.

No one can sell a quality made product for the same price as a thrifty product. Those who try to sell quality at low cost (try to compete with the thrifty lot) will inevitably go out of business because of the huge differences in fixed costs. Even if you buy a bajillion tons of Teflon, it still costs a far more than the equivalent amount of Mylar. The economics are just not on the side of quality, at least as far as capacitors go.

Plate, lead, and dielectric material choices all influence not only the cost but also the life expectancy and built-in signal degradation of a capacitor. It's a wonder that any affordable capacitor works at all with so much stacked against them. But yet numerous manufacturers find creative ways to lower costs and here are just a few examples of how that is achieved.

One way to lower fixed costs is to make the surface area of a plate appear larger than it is. In doing so, you can use less plate material and therefore less dielectric to make the same value capacitor. A trick called "etching" increases the effective surface area of the plate by roughing up the surface (creating ridges and valleys). This 3-D etched plate has more effective surface area than its 2-D counterpart however the resulting capacitance value varies because of the hill/valley dimensional differences (less/more dielectric between the plates at any given point).

Another way to lower costs is to "print" a conductive plate onto a dielectric sheet and stack these printed dielectric sheets on top of each other. By rotating even-numbered sheets 180 degrees, edge terminations to each layer can be made on opposite sides of the stack. 

Lead bonding techniques also vary from direct soldering, to welding, to crimping, to chemical layering, and many more. Lead material composition also varies from steel, to copper, to tin-alloy, and many, many others all aimed at an optimum cost-to-performance point. 

The methods chosen to mass-produce standard-quality capacitors vary significantly from those used for esoteric capacitors. You can view in-depth videos on how one example of volume-based capacitor manufacturing is achieved for ceramic capacitors at http://www.youtube.com/watch?v=gFEYuaY35Vo, tantalum capacitors at http://www.youtube.com/watch?v=8F1XMOE4kAU, aluminum electrolytic capacitors at http://www.youtube.com/watch?v=PkLG-_S5yl8, and film capacitors at http://www.youtube.com/watch?v=s39HCu7Zs2U.

Manufacturing processes vary by company and for esoteric brands their manufacturing processes are proprietary and well-kept trade secrets. For example, it is common knowledge that Mundorf uses two capacitors in series to lower (literally halve) the inductive property of their Supreme series capacitors. This means that two capacitors each twice the value of the actual capacitance desired are required to make one capacitor (two 50uF capacitors in series make one 25uF low-inductance capacitor). This doubles the cost of making that capacitor style but results in a capacitor that sounds different (faster, more detailed) from others that do not use this technique.

Other manufacturing techniques exist that focus primarily on the quality of plate and lead materials (high purity copper, gold content, silver content, etc.) each changing the sound while measuring exactly the same (or with minor differences) as their budget counterparts. Each time a variant of low-cost production materials is used, the price of its use increases. Plus the number of capacitors produced in a production "run" is also smaller so the economic benefits of volume purchasing are not achieved. 

Although this is not a thorough exploration of why capacitors sound different, it does give you an idea of why they could potentially sound different. There is a saying that applies to high-end anything (auto racing, photography, audio, etc.): the devil is in the details. It is at this highly detailed level where the differences between the state-of-the-art are and it is why a good quality capacitor costs what it does.

I hope you have enjoyed discovering how capacitor designs vary and why esoteric capacitors, if nothing else, cost more to make than the mass-produced varieties. When considering which style to buy and which to avoid, that is another whole can of worms beyond the scope of this series. 

Yours for higher fidelity,
Philip Rastocny

Skeptics are essential to keep us sane; skeptics do little to keep us inspired. Philip Rastocny, 7-16-2014

I do not use ads in this blog to help support my efforts. If you like what you are reading, tell your friends and please remember to reciprocate by purchasing some of my highly affordable works at Amazon.com. My titles include:

Wednesday, September 17, 2014

Capacitors: All Things are NOT Created Equal - Part 4

In Part 3 of this series, you learned what the three basic components of any capacitor were: two plates separated by an insulator (aka dielectric). Part 3's focus was on the insulator of non-electrolytic capacitor and how the material contributes to the overall cost of the final product. In this part, we will look at the plates to see how they also impact the sonic signature and price of this simple device.

Capacitor Components:
Plates (A and B) and Insulator (dielectric)

You may think that a good material choice for capacitor plates would be copper, gold, or silver based on their conductivity (the property a material has to efficiently permit electricity to flow through it) and you would be absolutely correct. However, these three materials also cost significantly more than another, that being aluminum. So the vast majority of capacitors use aluminum as the plate material of choice. But there is an issue with this material: it is difficult to make connections to it, especially when you consider how extremely thin the plate is.

Anyone who knows even a little about welding understands the issues behind creating a solid weld to aluminum. Unlike steel or iron, aluminum requires significantly higher heat since its melting point is much higher than the other three. Plus making joints between different materials is even tougher (say an aluminum plate to a copper wire). Here the copper tends to evaporate before a weld is achieved so crimped (physically mashed connections that do not use heat) are commonly used. 

Another option is to introduce a momentarily high temperature at a small spot to fuse a tiny portion of the two different materials together (called a tack weld). Tack welds, while they do work, only provide a small cross-sectional area for electrical conduction. This means that several tack welds are required in order for the junction to carry any significant amount of current without destroying the weld during normal use.

The other issue with using different materials in making crimped connections in capacitors is that the expansion rates of the two materials is different: one material expands more or less compared to another. Dynamic temperature changes inside of a connection over time cause the materials in that connection to slide back and forth: what was once solid becomes less so. Also, under certain conditions, tack welds can also create diodes at the joints meaning that instead of conducting a sinusoidal signal they conduct only half of that signal. The solution of course is intuitively obvious: use the same material for the leads as the plates or use two materials that are more compatible (weld at roughly the same temperature without evaporating either material in the process). Unfortunately, soldering an aluminum lead to a copper circuit is impossible so we are back to abandoning aluminum as a plate material of choice.

If low cost drives a design, aluminum plates are the best choice to save money. But because of the inherent drawbacks with bonding different materials together, higher-cost similar materials are desired for high-end audio. Remember, the conductivity property of silver is best followed in order by gold and copper. Each of these three materials readily bond together however over time dissimilar metal corrosion will occur at the joints (a slow degradation process that occurs at the molecular level). So again the best solution is to use the same material for the plates and the leads regardless of what material is selected. 

The next best choice would be copper plates and leads knowing that the conductivity losses are acceptable compared to the aluminum alternative. Or build a capacitor out of gold or silver with copper leads knowing that the conductivity will be better and the life expectancy will be less. Since the life expectancy of an average piece of audio gear is well within the time it takes for significant junction degradation to occur, such dissimilar materials are therefore highly desired.

So making a capacitor is more difficult than one initially suspects, especially if low cost is driving your design. Plate, lead, and dielectric material choices all influence not only the cost but also the life expectancy and built-in signal degradation. It's a wonder that they work at all with so much stacked against them. And we haven't even discussed how large values and mass-production issues introduce other problems with this simple design (we'll briefly look at them in Part 5).

Although this is not a thorough exploration of why capacitors sound different, it does give you an idea of why they could potentially sound different. There is a saying that applies to high-end anything (auto racing, photography, audio, etc.): the devil is in the details. It is at this highly detailed level where the differences between the state-of-the-art are and it is why a good quality capacitor costs what it does.

Yours for higher fidelity,
Philip Rastocny

Skeptics are essential to keep us sane; skeptics do little to keep us inspired. Philip Rastocny, 7-16-2014

I do not use ads in this blog to help support my efforts. If you like what you are reading, tell your friends and please remember to reciprocate by purchasing some of my highly affordable works at Amazon.com. My titles include:

Tuesday, September 16, 2014

Capacitors: All Things are NOT Created Equal - Part 3

Many factors contribute to how a piece of equipment or a loudspeaker sounds and one of these factors is the lowly capacitor. As you have read in my earlier posts, much of a design is driven by the budget for that particular piece of gear which is matched to a selling price. In order to stay within that selling price, a designer must make choices and increasing the cost of every component used in the design can hugely impact the final selling price, so even low-cost components like capacitors are carefully evaluated.

It does not make sense to use a $200 capacitor in a preamplifier you are trying to sell for $400 so the designer must look elsewhere for a suitable substitute. The alternatives are dependent upon may things and in Part 2 we looked at one published parameter that can give you a hint as to how a capacitor will sound: the ESR (equivalent series resistance). Also noted was that this parameter is not the "magic bullet" measurement and others physical design factors also contribute to the overall quality of sound. Let's look first at what a capacitor is and what it is ideally supposed to do.

A capacitor is basically two plates separated by an insulator (aka dielectric): three components total. So how complicated can this be? Well, if it were that simple, an Audio Research preamplifier would be far more affordable. Let's start by seeing what difference the insulator makes.

Capacitor Components:
Plates (A and B) and Insulator (dielectric)

A perfect insulator blocks 100% of the electricity from passing between the two plates. However, there is no such thing as a perfect insulator so now you can begin to see just one of the problems in capacitor design. Which insulator better acts like a "perfect" insulator (one that "leaks" zero electricity)? Fortunately, there is a measurement that can determine how much leakage occurs across the insulator and this measurement is known as the capacitor's leakage current for electrolytic capacitors (DCL) and the insulation resistance for all other capacitors (IR).

What this means is that some of the signal that is supposed to be blocked is not, and how much of this signal leaks through is a function of the integrity of the insulator. So using poor-quality (low cost) insulators is one way to save money on the design but the resulting sound may suffer. BTW, this leakage current is also a function of the operating voltage where higher voltages require better (or thicker) insulators and is one contributing factor as to why tube gear (which uses several hundreds of volts) costs more than transistor gear (which uses several tens of volts). In other words, a 1uF/400V capacitor will cost more than a 1uF/40V capacitor of the same design.

If one desires to keep the ESR low, then the insulator must also possess this desired property or the ESR will also suffer. Those insulating materials that have both low leakage and low ESR narrow the field just like narrowing your search for a new car using two selection criteria of automatic transmission and a six cylinder engine. And just like a 4-cylinder with automatic transmission has one criteria met at a lower cost, so does a six cylinder with a manual transmission have lower cost. But neither option is not what you want and therefore to get what you want it will cost more.

For the moment, let's look at non-electrolytic capacitors. The categories of insulators that possess both low ESR and high IR are plastic-based designs (polyester, polystyrene, and polypropylene), tantalum, and Teflon. While there are others (like oil-filled designs), these are the most common. So by knowing what you already know, what insulators do you suspect would sound better? Yup, you are correct: the ones that cost more.

The insulator material cost per unit area (volume) ranking from lowest to highest is: tantalum, polyester, polypropylene, polystyrene, and Teflon. So moving from a polyester to a polypropylene capacitor will cost more but would also improve the quality of the sound, given all other things being equal. And if there are eight signal-path capacitors in a design each of which have a cost difference of $0.25, then the build price of that design is increased by $2.00, a pretty steep rise in an individual component cost if a guideline of 10x-20x design cost to MSRP is assumed.

I personally use very expensive capacitors in my entire system and I enjoy the benefits of hearing those subtle details that are lost in less-expensive designs. All of these capacitors are upgrades from the manufacturer's component styles and since I hand-selected and install them myself, I have transformed so-so sounding pieces of gear into a very high-quality system.

For example, I recently added ultra-high quality 0.1uF/200V Teflon bypass capacitors to my signal-path crossover network design for the tweeter and the super tweeter. Since all of my electronics have also been upgraded with similar-quality components, the addition of these Teflon capacitors proved to be audibly beneficial although the RTA measurements show no difference. And I seriously doubt that I would hear the differences I do if the other electronics in my system had not also been upgraded (the weakest link in the chain syndrome). What changed was the inner detailing; the low-level resolution that was once smeared (and I knew not that it was smeared) is now crystal clear and beautifully distinct. These capacitors are truly worth their weight in gold.

In Part 4, we will look at the other component in a capacitor: the conductor material. Until then, remember that the world is full of compromises and therein lies the rub. If a designer makes the product too good, only a few can afford it and the sales volume will suffer; if the designer makes it affordable, the choice of components better be matched to the expectations of the buyer or the sales volume will also suffer. Which is right for you is akin to where you choose to put your money: either you invest in audio pleasure or in something else. One day, you realize that the limits you place on spending also put limits on your listening pleasure.

Just like a Lamborghini Veneno that costs thousands of times more than India's Tata Nano, a really good audio system costs thousands of times more than an iPod. However, when you drive a Veneno, you instantly understand why it costs what it does. And when you hear a high-end capacitor you understand why it costs what it does.

Yours for higher fidelity,
Philip Rastocny

Skeptics are essential to keep us sane; skeptics do little to keep us inspired. Philip Rastocny, 7-16-2014

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