As promised earlier, I plan to post articles on the history of electronics, power, audio, and radio.  I’ve always been interested in technological history, especially in the process of how technology we take for granted today came about. Over the years I’ve collected text books and old magazines and have done research in technical libraries and on the internet.  What I will be writing for ClariSonus will be a series of monographs on various subjects.  The first one is on the frequency of the power that comes from an outlet.

[A note on the research for this article:  I've been reading early issues of the Transactions of the American Institute of Electrical Engineers (AIEE) and the British publication, Journal of the Institution of Electrical Engineers (IEE), both available from Google books in pdf format.  In particular, a very good reference article about frequencies is: "The Technical Story of the Frequencies" by B.G. Lamme in the January 1918 issue of the Trans. of the AIEE. Also quite helpful are the various Wikipedia articles linked within and this one on utility frequencies.]

[Another note:  given that my research sources are English-language, the emphasis here is on the history in North America. The situation in Great Britain and Europe will mentioned, but not in as much detail.]

The frequency of the power we get out of our electric outlets has been fixed since time of our grandfathers or great-grandfathers, at least in the developed world. Yet we are aware that there two standards in the world: 50 and 60Hz, and we may have heard of other frequencies, such as 25Hz, 400Hz, and even DC.  One country, Japan, even has both 50 and 60Hz.  Where did these frequencies come from?  Is one better than the other?  What explains the geographical distribution of these frequencies?  This article will give the history of the frequencies and try to answer the questions above.

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As most of you know, the Rocky Mountain Audio Festival is returning to Denver (close to where I live) on October 10 through 12. As in the previous 2 years, I’ll be there, most likely wearing a Press badge, taking photos, and posting them either here or in the Loudspeaker forum of DIYAudio.com.

Two years ago, I had big plans to produce the Karna amplifier. but gremlins with the filament supply put that on the back burner - maybe some day. Later that winter, I had the Big Accident, which sidelined me for quite a while - six months to be allowed put any pressure on left leg, another two or three months to learn to walk again, and another several months to get proficient enough not to require a cane.

Those of you who saw me at last year’s RMAF probably saw me with two companions - Alexander of RAAL, and my cane. I’ve outgrown the cane, and Alexander will not only be back, but exhibiting his astonishing new omnidirectional loudspeaker.

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My friend René Jaeger turned me onto a huge site of service data and scematics: eServiceInfo.com.  The front page is somewhat intimidating, but there are good tools for browsing and searching.  It covers everything electrical and electronic. There is a facility to request data, there is a forum for asking questions, and a way for registered users to upload schematics and manuals.  Since the data is essentially user-contributed, the quality varies, but the few manuals I downloaded were good-quality scans.  All downloads are free (although limited to a maximum of 50 per day and 500 per month) with the site apparently supported by Google ads.

eServiceInfo appears to be based in Bulgaria and its users and contributors are world-wide, so there is a very international cross-section of devices and data offered. As a user and provider of web-based information sites, I’m sensitive to the details of site organization and find that eServiceInfo is one of the best I’ve seen for providing data downloads.  Check it out!  By the way, the audio directories are here.

As some of you might have noticed, the Clarisonus site was hijacked for the last few days.  Due to a misunderstanding between the web host provider and myself, the domain www.clarisonus.com expired. You then got to see the cute woman shown here.  The domain has been renewed and everything should be back to normal.

You may also have noticed that the site has been quite idle for the last few months.  There are various reasons for this, including non-audio related work, consulting work I can’t talk much about, and general sloth.  However, a dead site is no fun, so I will be making an effort to post at least once a week.  If there are no current projects or reports to post, I’ll dip into the historical archives, and do some posts on the history of technology, similar to (although probably longer than) the posts at Arcane Radio Trivia.  Lynn Olson has a few posts in the pipeline, too.

- John Atwood

Although audio is my main interest, radio comes in as a close second.  Radio predates electronic audio and much of audio’s technology has come out of radio.  I’ve stumbled across the site Arcane Radio Trivia and have found it so interesting that I have read every one of its posts, starting from April 2005. It is written by Jose Fritz (I suspect a pseudonym) who apparently has a career in the radio business. Jose also contributes record reviews to the Stranded in Stereo site.

Arcane Radio Trivia covers all aspect of radio imaginable: from technology, history, radio personalities, books about radio, to what stations Jose has heard on his frequent road trips. His views echo mine: skepticism of the growth of corporate radio, support of independent local stations, and heavy skepticism of the FCC and NAB (National Association of Broadcasters). The postings seem quickly written and often have spelling or grammatical mistakes, but the content is fresh, and he posts nearly every weekday! There are often week-long tutorials or history lessons and many good links to other sites. Sample some of his archives and I’d bet you will find yourself wanting to read “just one more posting”.

Things are slow this summer.  I’ve been working on some Artemis Labs projects as well as reorganizing the house.

You may have noticed a trickle of pornographic spam in the comments over the last few months.  I think I have stopped most of them from coming in by turning off “pings”, which allowed track-back comments.  I just deleted a comment from “James” today because of off-topic web-links.  If your comment is not relevant to the topic discussed and especially if it contains irrelevant links, it will be treated as spam.  If you disagree with the deletion, you can post a follow-up, but keep in mind: this blog is not meant to be a repository for your advertising links!

As part of the spam clean-up, I’ll be trimming some of the registered users that have spam-related names and have posted no relevant comments.  If you accidentally get caught up in this clean-up, just re-register again.

- John Atwood

The issue of over-compression in recent pop music is getting around in the business, with the latest reaction being the formation of a non-profit group, named “Turn Me Upâ„¢” to encourage better dynamics. From their web site:

Turn Me Up!â„¢ is a non-profit music industry organization campaigning to give artists back the choice to release more dynamic records. To be clear, it’s not our goal to discourage loud records; they are, of course, a valid choice for many artists. We simply want to make the choice for a more dynamic record an option for artists.

Today, artists generally feel they have to master their records to be as loud as everybody else’s. This certainly works for many artists. However, there are many other artists who feel their music would be better served by a more dynamic record, but who don’t feel like that option is available to them.

This all comes down to the moment a consumer hears a record, and the fear that if the record is more dynamic, the consumer won’t know to just turn up the volume. This is an understandable concern, and one Turn Me Up! is working to resolve.

How this will be accomplished is not very clear, although the presence of an official Turn Me Up! certification and cool-looking logo (at the top of this article) may help break the positive feedback cycle that seem to make record labels and artists want to compress their music to the max. The fact that the metric for determining whether a recording merits certification has still not been decided is troubling and needs to decided soon for the effort to take off. I really hope it succeeds, since the industry is killing itself with its current compressed mess.

The front page of Turn Me Up’s home page has a very comprehensive set of links to articles and papers on the issue of over-compression, highly recommended for those interested in this issue.

This post comes a little late, since I’ve just spent two weeks in Morocco on a Country Walkers’ walking tour. Morocco is very interesting, with a rich culture and really friendly people. The weekend before flying to Morocco, I attended a “Tube Tasting” at Oswald’s Mill in eastern Pennsylvania. Here is the mill itself:

It is a 18th century grain mill built right into the house, and has been refurbished over the last ten years by Jonathan Weiss. Jonathan’s “Tube Tastings” have been an invitation-only event since 2002, where people into vintage, exotic, and exceptional home-built equipment can set-up and compare their projects. Jonathan is also a world-class cook, and cooked all the food for the gathering - and the food was fantastic!

The main listening room takes up nearly all of the third floor. The open beams, various vintage paraphernalia (verging on steam-punk), and the 3rd-to-4th floor opening (see the large windows on the picture to the left) gave plenty of room for the speakers to breath. The window openings in the two-foot thick stone walls made perfect turntable mounts.

The impressions given in this article can only give a glimpse of the totality of the tasting. The official 2008 Tasting page is not yet up (although 2003 through 2007 tastings can be seen here), but there is a pretty complete review of the 2008 Tasting at the 6 Moons site, with many tasty pictures. If I leave anyone’s equipment out of the following text, it is due to my inability to listen to everything plus my fading memory of the event three weeks ago.

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Once again I will impose on the hospitality of John Atwood and write an essay that is entirely off-topic - so here goes, folks:

I’ve been thinking about the implications of Peak Oil and climate change. I’m not one of the chicken-little types that thinks the electrical grid will collapse in ten year’s time, or agriculture will run short of (fossil-fuel based) fertilizer. I’m enough of an economist to know the market, even though it is heavily manipulated by oil companies and OPEC, will still decide how the transition away from fossil fuels will happen. We won’t just suddenly run out one year; instead, the price of oil will go up - and up - and up, broken by the inevitable market disruptions and political turmoil. So the long-term (over decades) trend will be steadily upward, descending only when fossil fuels are almost entirely phased out and used only for chemical feedstocks (instead of fuel).

The survivalists think that Western Civ will collapse of its own weight and complexity, and the USA, at least, will descend into some kind of Mad Max end-times movie of guns, stored-food, and local-militias. I don’t. The market will speak instead. People forget that until very recently, the price of gas was only a small part of the total lifecycle cost of a car or truck.

Think about it. If a $20,000 car is driven for 120,000 miles over a ten-year lifetime, and consumes 20 mpg, it uses up 6,000 gallons of gasoline. At US$1 a gallon, the price of gas from Reagan through Clinton, that’s only $6,000. Big deal. No wonder Detroit sold a lot of upscale body-on-frame trucks disguised as SUV’s. Why not? Big and luxurious, the way Americans like it. If the 5,000 lb behemoth consumes a miserable 13 mpg, that’s still only about $9,000 over the life of the vehicle. It’s really not all that much if you want to haul your family, and a boat or trailer, out to the boondocks in air-conditioned CD/DVD player comfort.

The 13 mpg SUV looks a little different at $4 a gallon. Now that’s $37,000. Uh-oh; that’s the price of the vehicle. At the existing European price of $8 a gallon, that’s $74,000. Now we’re talking real money. If worldwide Peak Oil becomes a reality over the next ten years (and independent consensus opinion in the oil industry is that it will), then the USA will be seeing $10 a gallon - before 2018. Now that SUV will be eating $90,000 over its lifetime. Most SUV’s will see the junkyard before the ten years is out - the operating costs will be just too high for many people, especially for an aging, out-of-style vehicle. We’re not talking about a collectible musclecar here, like a Shelby Mustang, but one of millions of Ford and GM family-haulers with a trailer hitch on back.

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I recently stumbled across a source of DRM-free music that I hope represents the future of music distribution. Pristine Classical sells music, mostly classical, but some jazz and blues also, in a variety of forms, ranging from MP3 downloads to physical CDs. The prices are not very cheap, especially since they are in Euros, but no protection or DRM is attached, so you can back them up or trade them with your friends forever. (A reminder of the futility of DRM is in this Ars Technica article about how Microsoft will turn of their MSN Music license key servers at the end of the year. Your licensed (not purchased) music will still run on the computer it is licensed to until something changes - i.e. OS upgrade, hardware change, etc. I’ve never had a Windows computer be this stable for more than a year.)

Pristine Classical was started in 2005 by Andrew Rose as a offshoot of his Pristine Audio business of restoring and remastering of old records and tapes. He has apparently made deals with the copyright holders of some of these classic works so that all recordings are fully legitimate. The age of the recordings go from about 1955 back to the early electrical recordings of the late 1920s. As such, you won’t hear stereo spectaculars, but the recording quality of the late 1940s and early 1950s recordings can be quite good, if only mono. An added plus is that the details of each restoration are explained for each recording. A particularly difficult restoration is explained in the notes for this 1950 Decca recording.

An outfit that sold only MP3 downloads would frankly not interest me, since I consider the sound degradation too significant, even for vintage recordings. However, Pristine Audio recently has started offering FLAC lossless encoding on many of their recordings, in a 44.1K/16-bit format. Not only that, but they have just started offering 48K/24-bit FLAC versions that reflect the resolution of their original restoration. These are nearly twice the cost of the ordinary FLAC versions, but would offer the ultimate quality. My own experiments with resolution and sample rate show that higher bit resolution is a bigger improvement than higher sample rate.

I bought several of the classical FLAC recordings while I was on the road (I still don’t have high-speed internet at home), and when I got home played them on my main system. So-called restoration of old records can sometimes take the life out of the recordings, but Pristine’s restorations were tastefully done. No major clicks or pops and the surface noise is low, but the details are there. On the whole, I liked the restorations.

The Pristine Classical site is rather cluttered and busy, but that is partly because they offer many versions and services, including cue lists and color CD insert printouts for each recording. The following screen capture shows the general pricing structure:

With our poor dollar-to-euro exchange rate, the prices seem a bit high, but considering you are getting the full musical and sonic equivalent of a CD, with the cue lists and cover art, and no DRM, it isn’t so bad. I’m impressed with their offerings, and hope they do well.

One of the more eye-catching features in a lot of home-built “extreme” tube audio amplifiers are mercury-vapor rectifiers. Their hazy blue glow that is modulated by the current draw of the amplifier adds to the organic life that attracts people to vacuum tube amps. But concerns about safety have polarized the audio community, with some fearing that their homes may become EPA hazard sites! And, do mercury-vapor rectifiers have a sonic benefit in tube amplification? This article will try to answer this question. A follow-up article by my friend, Wally Chan, is a well-researched look at the safety of mercury-vapor tubes in the home. (note: This picture taken by and supplied by Lynn Olson.)

Physics & History

First, some history and definitions. Part of the breakthrough in technology that allowed radios to be run off of home AC power, rather than storage and dry batteries, was the development of inexpensive rectifiers. In the high-power industrial field, conversion of AC to DC was traditionally done with motor-generator sets, but these are expensive, noisy, and unreliable. High-vacuum rectifiers became available in the 1920s, but the early ones (e.g. 207, 81) had high voltage drops, making them inefficient. However, once the physics of gas discharges was understood, the low voltage drops in a gas discharge could be used to make a more efficient rectifier. Mercury vapor gives a voltage drop of about 11 volts, essentially independent of current flow. The first mercury rectifiers were large “pool” rectifiers that used a hot arc discharge from the surface of the mercury pool to generate the electrons and ions needed to conduct current through the rectifier. The smaller ones took the form of large glass bulbs with glass arms coming out of the sides for each anode. The larger ones, handling thousands of amps, were built into water-cooled metal tanks. On a large industrial scale, these were very efficient, and used right up until the time they were replaced by silicon rectifiers in the 1960s and 70s.

For smaller scale operations, hot-cathode mercury-vapor rectifiers were developed. These used oxide-coated cathodes and were processed like high-vacuum rectifiers, but a small amount of mercury was added before the glass bulb was sealed. Once the tube is warmed-up, the mercury vapor allows conduction as soon as the voltage from plate to cathode reaches the ionization potential. If a metal grid is placed between the cathode and plate, a thyratron is formed, where conduction can be inhibited by a negative voltage between the grid and cathode. Once conduction starts, in either a rectifier or thyratron, it doesn’t stop until the anode voltage falls below the ionization voltage. The thyratron is analogous to the silicon controlled rectifier (SCR).

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Wally Chan is a retired manager from Tandem Computers (now part of Hewlett-Packard) with a strong interest in science and engineering. I asked Wally what he knew about the hazards of mercury as used by audio enthusiasts and he came up this well-researched report. - J. Atwood

Mercury Vapor Rectifiers: Breakage in the Home

by Wally Chan

Mercury quantities and releases from household and industrial uses should be minimized because of the cumulative poison effects [1] [2] [3] [4] [5]. One uncommon specialized use is the mercury vapor rectifier, containing approximately 10ug of mercury vapor at 25 microns pressure (60 degrees C) and a total of .5 g of liquid elemental mercury [6]. If totally absorbed into the body, .5 g of elemental mercury has resulted in death, and approximately 1 to 4 gm is regarded as a lethal dose. But what risk occurs in practical circumstances from broken mercury vapor rectifiers?

In older homes, traces of mercury vapor are emitted from mold growth inhibiting paint additives [7], as well as from past thermometer and other spills. To control chronic exposure risk to continuously exposed householders, especially the young, an ATSDR recommended upper limit for mercury vapor in residences is 1.0 ug/m³ for elemental mercury [8]. This is a tighter limit than the OSHA occupational upper limit .1 mg/m³. The 10 ug of mercury vapor from a working rectifier, if suddenly released into a reasonable sized, multiple m³ volume room, will be well under these safety recommendation limits. However, there is still the question of evaporation of the remaining .5 g of liquid mercury into the room air. It turns out that vapor production is slow enough that chronic exposure over many years is the primary concern.

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