John Broskie's Guide to Tube Circuit Analysis & Design


"The reports of my death have been greatly exaggerated."

 7 November 2004

What Have I Been Doing
“The reports of my death are greatly exaggerated.” So said a telegram sent by Mark Twain from London to a newspaper in the United States after it had mistakenly published Twain’s obituary. Well, the same can be said for the Tube CAD Journal and myself. We both persist. I have moved back to California; all moves are painful, but this one was made worse by having so much stuff to move while keeping my toddler safe and out of the packing and unloading of boxes. And I have spent a great chunk of time remaking the TCJ Push-Pull Calculator into two revisions, the first minor, the second profound and extensive.

Now in version 2.0, the TCJ Push-Pull Calculator program holds a rebuilt simulation engine, the ability to create user-defined reports as PDFs, more Graphs, including 3D graphs, a help system, a target-idle current utility, a redesigned array creation utility, transformer primary & secondary RDC inclusion, user-defined transformer definitions saving, enhanced result display, and an added array result grid. Most of these enhancements were the result of feedback from the readers who bought the program, and everyone who bought version-1 will get version-2, as soon as I firgure out how. Many thanks. I have enjoyed corresponding with this private club of sorts, as the tube-push-pull fancier strikes me as being a less nervous than the members of cult of the single-ended amplifier (the one I happen to belong to, ironically).

Having learned new techniques from the TCJ Push-Pull Calculator project, I then turned my effort on the TCJ My Stock DB program. It too has been updated to version 2.0 and it is well worth a second look, as it is much improved. It now list all of your parts in one database, part images display, one-click web searches for information, vertical and horizontal grids, reports as PDFs creation, graphs added in both pie & bar in both 2D and 3D, more powerful database searches, an added help system, editable drop-down lists for location, projects, brands, styles, vendors and more.

Additionally, I have switched Web design programs, having gone from Microsoft Publisher to Macromedia Dreamweaver, a wise decision, but a steep learning curve. (In addition, I had to manually cut, paste and size hundreds of schematics and the text that accompanied them—and some links I am sure will not work. Please email me if you find broken links; I assure you it was not intentional.) I plan on coming out with a new full-fledged Tube CAD Journal issue in the near future; but for right now, I plan on posting more blog entries.

As I have been visiting blog sites for inspiration for the new TCJ blog, I have become a fan of two cultural/political blog sites: Roger L. Simon’s and James Lileks’s blogs are a daily delight for me. Simon is a famous mystery writer, both novels and screenplays, and that says much of it. Lileks is also a writer, but less famous, and his genre is more difficult to define, something like "contemporary retro"—he is like a more intellectually muscular, funnier version of Prairie Home Companion's Garrison Keillor. Both Midwesterners, Lileks and Keillor draw from an American past when crime was rare and vegetables were overcooked, but Lileks revels in a more recent past than Keillor, somewhere around the 1950’s.

Both Simon and Likeks are men I would like to share a beer or two with (Anchor's Liberty Ale would be my choice), not because they would necessarily agree with me—or even with each other—but because both are true individuals, in Aristotle's sense of the word. For Aristotle, being an individual* meant much more than it does today when "individual" and "person" are interchangeable, as in "The police arrested two individuals trying to break open a Coke machine yesterday."

Where have I been?
Well, for the first third of this year, GlassWare (i.e. me, with help from my beloved and beautiful wife, who in no way is proofreading this over my shoulder) was operating out of Ann Arbor, Michigan; since then, we uprooted ourselves and moved to Sacramento, California, where Arnold the Governator also lives. It’s great to be back in the land of great weather (in the first five months, only one day was less than splendid; it rained). Yes, it does get roaring hot on summer afternoons, but nights are cool and the Delta Breeze performs wonders in providing free air-conditioning.

I understand that the Sacramento city government's unofficial motto is "This isn't New Jersey: we're not corrupt, just inept." Maybe, but I haven't run into problems with city government yet.  For me, there are two main problems with this city. First, while real estate is half as expensive as Silicon Valley (where the average house goes for 600 to 700k), it is still expensive relative to Ann Arbor, whose real estate is expensive relative to the rest of Michigan.

The second problem I have with Sacramento is more fundamental: that while it has everything you would want (food, books, entertainment, nature), none of it is particularly close together, so you end up driving huge distances. Other than in the old downtown, built before laws were passed against intelligent, and more importantly, interesting high-density and mixed-use urban development, all other development (and there is a lot of it) is on the Modern-Endless-Suburban-Sprawl model (MESS for short). Consider this: the most desirable cities to live in America—say, San Francisco and Carmel in California, and Boston and Charleston on the East Coast—are illegal. They are illegal to reproduce because of zoning laws, laws that conform to modern city-building practice as understood and taught (until very recently and in all but a few places).

Since WWII, we have “known better” than to have short blocks and narrow streets, blocks that all at once hold stores and restaurants and apartments and houses both large and small, streets that tightly wind and twist. We know that everything must be segregated and centralized to its pre-designed place; that all big-box stores—Home Depot and Costco—go in one corner of the city, while all smaller stores go in strip malls, and the university-sized high school goes in another place; that all houses must be the same size and cost the same in a new development; that suburban streets must be wide and lead nowhere; that you can only have a few main artery streets to move about town, so walking is not only difficult, but pointless; that every new city in America will be as unrelievedly uniform and as indescribably boring as any other new development in America; that living in California should be no different from living in Texas, or Ohio, or Louisiana, or Pennsylvania, save for the differences in weather. Never mind that we have gained weight, that we are losing leisure, and that our souls long for the more interesting, altogether more charming, more human cities, the cities that are illegal to build today in most of America. How much more lucky is Europe in that most of it was built before we new better, when cities were only built in accordance with human needs and not city planning science.

Now, consider this: isn’t our desire for tube-based audio much like our desire for living on Lombard Street in San Francisco or on Beacon Hill in Boston; or for the same reasons, staying a quaint bed and breakfast rather than a sterile Holiday Inn; eating in small, hundred-year-old Italian restaurant in San Francisco, rather than at a modern formica-clad chain restaurant in suburbia? Solid-state amplification is clinically, certifiably hygienic; it is more efficient, less distorting, safer, and cheaper than the tube alternative. Yet—and yet again and again—yet who wants to listen to it?

Today, no college teaches its electrical engineering students how to design a tube amplifier because every expert knows that the solid-state amplifier is better. No sensible chain store would today think of selling tube amplifiers. Yet, old tube amplifiers still please, while new solid-state amplifiers chill our ears and old solid-state amplifiers can wring confessions from the innocent. Yet, at its best, solid-state gear is only sterile and boring; at its worst, gritty and brittle. Yet, we do not listen to music with laboratory-calibrated microphones, but with human ears, frail and flawed ears yet able to hear beauty and genius riding on sound pressure, ears that long for human enjoyment. Fortunately, designing and building tube gear is not illegal—well, at least not yet. (Maybe after they have finished outlawing lead-filled solder, they will get around to it; something to do with global warming, no doubt.)

I do miss Ann Arbor, the city that always makes the top-twenty-places-to-live list—and there is much to miss—but California feels like home (the East Coast could feel like home, but I doubt the Midwest ever could, in spite of having some of the nicest people I've ever met). While in the Midwest, I visited four hi-fi shops with pretensions to high-end status. Sad, truly sad. In the nicest store—the cleanest and most orderly and with the best quality equipment—I asked where the tube gear was hidden, as none were in sight. Groans. The salesman asked, “Are you from California?" “What makes you ask,” I replied. His answer was that Californians always asked that question. Too bad they couldn't answer yes.

At the second and certainly the most depressing hi-fi store—poorly lit, with dirty carpets, where all the new equipment seemed somehow old and used—this same question provoked actual ridicule from a condescending salesman. "Why would you want to buy a tube amp?" he spit out with disgust. "Other than better sound and higher resale value, no reason," I replied. "That's stupid," was his witty retort. He then yelled out to his cohort, “Hey, can you believe that this guy is looking for tube amplifiers?” His slack-jawed coworker joined in by sniggering at my expense. Intriguing, puzzling, truly amazing.

Now, insulting a customer can be an effective sales strategy, if and only when the customer is insecure and, most important, the salesman follows the insults with a dangled carrot of potential complements and a promise of comradery, as the unconfident will often jump at the slightest chance to be liked, even if that means buying $2,000 worth of patch cords. Yet, so Machiavellian a strategy was beyond these two laughing jackals. I asked before leaving if they knew of any hi-fi stores that sold more expensive equipment, as I had budgeted $43,500 for my new system and I wanted to spend it in just one store.

The third store was owned by a nice enough guy who explained that home-theater systems kept him in business and that selling any high-end stereo equipment at all was tough in Michigan and that he had once tried selling tube gear and he lost his shirt in process. Honest, but nonetheless depressing.

The last store actually sold some tube gear, albeit hybrid tube-solid-state gear. Unfortunately, the salesman was worse than inexpert, as he believed himself supremely knowledgeable and he was appropriately arrogant. He told me that the electrodynamic loudspeaker that stood in front of us was an electrostatic loudspeaker. Puzzled by the conventional, generic, Wall-Mart appropriate speaker drivers before me, I kept asking if he was sure and he grew more snotty with each affirmation. I asked to see the brochure, which plainly confirmed the loudspeaker’s magnet and wire principles. Obviously losing patience with my relentless querying, his reply was that, “They were electrostatic-electrodynamic speakers, of course.” I was in a surprisingly good mood and I was tickled by his obduracy. I leaned over and whispered, “You are absolutely clueless aren’t you? You know nothing of stators, polarizing voltages, permeability, BL factors, magnetic circuits, Faraday loops, and inductive and capacitive impedance, right?” Guiltily, sheepishly, he mumbled, “Maybe.” 

I can’t comment on the audio store alternative offered in Sacramento area, as I have yet to search out high-end audio stores here. Soon. Still, I don’t expect to be too overwhelmed by what I find. Today, tube audio is but a small fraction of audio in general. And sadly, Audio—the art, practice, and science of designing home-audio electronics—stands abandoned and forgotten, surviving as it does in the shadows of the computer, MP3 player, digital camera, and home theater system, ignored by the research scientist, bereft of popular media interest. The spotlight has moved elsewhere. Basically, many will argue that all that can be done with home audio has been done. Audio is the orphaned child of our technological age.

If Audio is the orphaned child of our technological age, then—maybe—Tube Audio is the little orphan, Oliver, who asks, "Please, sir, I want some more." Well, more is just what I plan delivering: more articles on interesting tube circuits, more ancillary information on topics like power supplies for tube projects, and more blog entries and more articles.


*For Aristotle, the individual is an individual in the extreme. As Aristotle would put it, the individual is highly differentiated from all others because he cherishes and pursues his own private passions. A nice paradox is set out by Aristotle when he says that individuals seek, not shun, other individuals. Paradox? Extreme individuality means that fewer can understand or share one's private perspective. Yet, the individual is not reclusive; instead, he cherishes the company of other individuals, as he recognizes and respects individuality in others. In other words, he recognizes and respects those who cherish and pursue their own private passions. On the other hand, Aristotle points out that those who are less differentiated do “desire the company of others, but avoid their own. And because they avoid their own company, there is no real basis for union of aims and interests with their fellows.” I am sure that William Buckley’s and John Kenneth Galbraith's famous and long-lasting friendship—otherwise a paradox, as these men disagree greatly—only makes sense if Aristotle was right.




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TCJ Push-Pull Calculator
Version 2

TCJ PPC Version 2 Improvements

       Rebuilt simulation engine
       Create reports as PDFs*
       More Graphs 2D/3D*
       Help system added
       Target idle current feature
       Redesigned array creation
       Transformer primary & secondary
              RDC inclusion
       Save user-defined transformer definitions
       Enhanced result display
       Added array result grid

*User definable

TCJ Push-Pull Calculator has but a single purpose: to evaluate tube-based output stages by simulating eight topologies’ (five OTL and three transformer-coupled) actual performance with a specified tube, power supply and bias voltage, and load impedance. The accuracy of the simulation depends on the accuracy of the tube models used and the tube math model is the same True Curves™ model used in GlassWare's SE Amp CAD and Live Curves programs, which is far more accurate than the usual SPICE tube model.

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Sacramento city government's unofficial motto is "This isn't New Jersey: we're not corrupt, just inept."



San Francisco and Carmel in California, and Boston and Charleston on the East Coast
—are illegal.










Isn’t our desire for tube-based audio much like our desire for living on Lombard Street in
San Francisco?





Fortunately, designing and building tube gear is not illegal—well, at least not yet.


While in the Midwest,
I visited four hi-fi shops with pretensions to
high-end status. Sad, truly sad.



He then yelled out to
his cohort, “Hey, can
you believe that this
guy is looking for
tube amplifiers?”
















Audio is the
orphaned child of our technological age.           Copyright © 1999-2004 GlassWare           All Rights Reserved