John Broskie's Guide to Tube Circuit Analysis & Design
27 December 2006

Happy New Year. I am extending the Christmas sale until the end of the year, December 31st, 2006, as many are so busy right now with the holidays. Some calculating how much money they have left after Christmas; and a few lucky ones are tallying how much they received on Christmas. (Besides, I am too busy to go turn off the sale at the Yahoo! store.)


More Zune Thoughts


Yes, I still love my Zune. I have filled its hard drive with 27.5 Gig of music, hundreds of albums, and 4,273 songs. Rock and Popular Vocal predominate, followed by World, Blues, then Jazz, and, finally, classical. Interestingly, this is the exact inverse ratio of my music collection. How or why did this happen? An MP3 player’s music library, like the books and magazines one takes aboard an airplane, should be a light, frothy, insubstantial mix, as the many short listening sessions and high background noises that accompany moving about in the world do not befit anything as grand or long as Mahler’s 3rd Symphony (97 minutes), just as Tolstoy’s novel, War and Peace, deserves more than 40% of one’s attention. On the other hand, a Zune or iPod is perfect for harvesting interesting snippets from old familiar albums. For example, I had forgotten that Badfinger had more than one hit and that I liked the band’s music as much as I do.

Second-rate is okay by me…or should I say, What should you listen to when only the best won’t do? Most classical aficionados place Beethoven and Bach at the very pinnacle of greatness (I, like so many others, dropped Brahms from the Three Bs long ago, although I greatly enjoy his music). These two composers sit on the highest thrones of artistic genius and one could devote a lifetime of careful listening to just their oeuvres. Yet, few do. Why?

La Rochfoucauld wrote that, “Neither the sun nor death can be regarded steadily.” To this list, we can add all the greatest artistic triumphs. Complex and exhausting, listening to the entire Beethoven’s 9th Symphony requires a huge investment of time and effort. (Although this is one of my top-ten favorite pieces of music, I only listen to the whole of the work once every few years.)

Beyond the rigorous demands made on us by the greatest works, the second-rate often proves more interesting. I believe it was T.S. Elliot who first pointed out that a great artist seldom creates a new artistic tradition; rather, he completes it, concluding, and exhausting a style or genre, mining and evacuating the last vein of artistic possibility. Shakespeare did not invent the tragedy, nor did Bach create the concerto. But after Shakespeare and Bach, no one wrote Shakespearean plays or composed Bach-like concertos. On the other hand, the lesser artist, eager to stake out his own artistic domain, invents wildly, indiscriminately, as creating the new is easier than mastering the old. As Eric Hoffer put it:

“Total innovation is the refuge of the untalented and the innately clumsy. It offers them a situation where their ineptness is acceptable and natural. For we are all apprentices when we tackle the wholly new, and we expect the new to show the apprentice's hand—to be clumsy and ill-shapen.

Yet, however untalented and clumsy, the innovators have a vital role to play. For it is the fate of every great achievement to be pounced upon by pedants and imitators who drain it of life and turn it into an orthodoxy which stifles all stirrings of originality. The avant-garde counteracts this deadening influence, and fulfills the vital role of keeping the gates open for the real talents who will eventually sweep away the inanities of the experimenters, and build the new with a sure hand.”

Moreover, any new fashion, whether in clothing (or lack of clothing; hello, Britney Spears), music, or politics (hello, Barack Obama), arrests our attention, if only briefly. (In audio, new distortions are more compelling than old distortions. To be successful—at least in the short run—in the high-end audio world, you do not have to produce a more accurate, cleaner-sounding piece of audio equipment, only a newly distorting device. As Woody Allen said in his Rip-Van-Winkle story, Sleeper, after tasting the food of the future, “This stuff tastes awful. I could have made a fortune selling it in my health food store.” Anyone ready for whale-oil and seaweed coupling capacitors? A bargain at only $1,200 each.)

Do not get wrong here; I love silver. Sure, gold is wonderful, but silver is more practical. For example, I love Honda cars. Yes, Ferrari and Rolls Royce cars are great, but my Honda Fit and Odyssey are also great in a lesser, but more practical sense. I love Art Pepper, Dexter Gordon, Benjamin Britten, Alan Hovhaness, Arvo Pärt, and Dmitry Shostakovich—each is vastly talented, none is of the first order, although each is at the top of my play lists. Silver is just fine; tin and zinc are, of course, a different story. Well, the Zune and iPod perfectly suit the silver of the music world. Because they hold so much music, because navigating through the immense library is so easy, we are free to drop in and quickly examine the most interesting pieces of sonic silverware.

Practical Zune matters
I just read another grumpy review of the Zune. Once again, the reviewer was perplexed and irritated that the Zune did not function the same way his iPod does. He kept swirling his fingers over the controls and nothing happened; much like someone who drives a stick-shifted car insisting on pressing an imaginary clutch peddle and needlessly shifting gears in a car with an automatic transmission. What this maladroit did like, however, was the Zune software that resides on your computer. Amazing. Reading such an inverted, misguided review is bad enough, but having it appear as it does in a mainstream computer magazine, depresses greatly.

The Zune software falls into the zinc category. Too much is missing, too much is assumed. I would like to see two snapshots: one of what music resides on my computer and one of what is found on the Zune’s hard drive. I want to know what the percentages are for the genres on ether device. (For example, 43% Jazz, 0.002% Rap, 12% Folk…) I want to be able to choose the compression ratio used to encode each album, not a single universal ratio that applies to all albums. (For example, your phone is a very low-fi device, yet you can understand all that said to you through it. In the same way, spoken-word albums do not need the high-fidelity encoding that befits Beethoven or Bach.) But most of all, I want not only to know where I am in the music library, but where I came from and where I can go. In the name of all that is decent, it should never take longer to create a playlist than it takes to listen to it.

Click on the above image to see an enlargement

The above screen capture shows a replacement software program that I am writing for the Zune. It is not complete. How could it be? It took Microsoft several million dollars and hundreds of programmers, project managers, field testers and quality assurance technicians, and thousands and thousands of programmer-hours to create the overly-basic and partially-lame Zune program. In other words, it should take me about a month or two to finish this program.

The goal is to be able to move easily and quickly through thousands of music tracks, hundreds of albums, many videos, and countless baby pictures. If I want to collect my favorite ten Buddy Guy songs or ten Blues songs, I shouldn’t have to wade through many screen refreshes and program back steps. I want to be able to filter the database so that only Jazz covers of “Summertime” show. Most importantly, I do not want any of the program’s real-estate wasted on vast stretches of white-space (in this case, black space), no matter how pretty.

MS Zune program. Click on the above image to see an enlargement



The Zune player improvements
I would love to see Microsoft add a photo-cell to the Zune, so that the screen’s brightness and contrast would automatically adjust to the appropriate level for the ambient light. In addition, it would be great if the last volume level that a song was played at was retained in the database, so that volume adjustments would be less frequent.

A nice feature would be a 6-inch headphone line extension. Why? At some moment, you and your Zune will go in different directions. So, rather than having the headphone’s wires ripped from the plug, the headphones would just unplug from the extension.

While I am at it, how about a kickstand for the Zune? I have ripped some DVD video to the Zune and it, amazingly enough, works. By that I mean that you can actually watch a movie on the little screen. But holding the Zune in just the right position gets to be a drag, so a collapsible kickstand for holding the Zune at the right angle for watching would be great.

Although almost half of the classical music I own makes use of human voice, I only own four opera recordings. Why the discrepancy? Opera and golf are siren calls that I have resisted. Knowing that each could consume my life, I do not want to succumb, no matter how much enjoyment I might derive from their pursuit. Well, a CD I recently bought of Anna Netrebko singing highlights from La Traviata, Violetta, was accompanied by a free short DVD, which holds a few MTV-like videos of Ms. Netrebko lip-syncing. She is indeed lovely, about a thousand times more talented than Britney Spears, and a fairly good soprano as well. I ripped the videos to my Zune and I have to admit that her singing did come alive. I am not sure if watching Joan Sutherland sing the same arias and duets would have the same effect, as Ms. Netrebko is not only lovely, but a fine actress as well. I can feel myself being pulled in…

(Speaking of big screens, one crazy thought I had was to write a program that would convert text files into a series of image files, 320 by 240 pixels big, so that while waiting in line at the bank I can read essays that I have downloaded off the Web, something like Sony's eBook.)


Back to music
Once again, I cannot over stress how much musical enjoyment I am getting out of my Zune. I must own nearly one hundred CDs that I have played only once. With the Zune, I am giving these albums a second chance; whereas if I were left only with my home system, these albums would languish still on the shelf. Why? Just too much hassle to swap the disks in and out.

By the way, the ear-buds that come with the Zune—like those that come with the iPod—stink. I recommend all of the Grado headphones, as they all sound good, although they are rather large and heavy. But the headphones that I use the most are the AKG K26Ps, which are also the most uncomfortable headphones that I have ever owned (as many must have guessed by now, I have a particularly fat head). So, why do I use them? For one, they fold up nicely; second, they acoustically seal off the outside world; finally, they sound surprisingly good.

Many think nothing of spending thousands to make only the smallest increment in sonic improvement in there stereo systems. $3,000 power cords, for example. But for only $239 you can make an enormous increase in your enjoyment of your music collection. (Having filled up my Zune, if my wife wouldn’t think me crazy, I would love to buy a second one and to fill it with just classical music. A 60-Gig Zune would not be as good, as it would take much longer to access the songs and classical music has its own conventions and directory structure that best suit a separate device.)


A real solution

The big problem that the Zune and the iPod face is that they are too cheap to be taken seriously. Well, the kind folks at ReQuest have the solution. For a little over $18,000, you can own an S4.2500, which is in the words of Jazziz magazine, “like an iPod on crack.” This premium digital media system holds 1.5TB of storage; yes, terabytes. It can hold 8,000 CDs in MP3 file format. It just might sound good as well. But that is not as important as the ego-boost such a product can perform. Imagine the looks of envy, something not even two Zunes could match.


Next time
We take another look at the last OTL design. I should have it posted before the weekend.






Kit User Guide PDFs
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The TCJ Stepped Attenuator
This specially designed stereo attenuator uses three rotary switches and 32 resistors to yield 36 volume positions. This hybrid attenuator uses a combination of both ladder- and series-stepped attenuators. In the first six positions, the attenuator is just a ladder attenuator, with no more than two resistors in the signal path; thereafter, the attenuator uses both a ladder and series configurations, with never more than eight resistors in the signal path. With -2dB decrements, a maximum of -70dB of attenuation is possible; with -1dB decrements, a maximum of -35dB of attenuation.

The center knob controls both channels, and offers six large decrements; the flanking knobs offer six fine decrements for each channel, creating a volume control and balance control in one easy-to-use stepped attenuator.

This clever attenuator uses fewer resistors (only 32) than would be expected from a conventional 32-position stepped attenuator, as two series attenuators would need a total of 72 resistors; and two ladder attenuators would require 140 resistors. In addition, the PCB holds dual sets of resistor pads, one wide and one narrow, so that axial (composition, wire-wound, and film) and radial (thick-film and bulk-foil) resistors can be used without extra lead bending.

Although designed to go with the Aikido amplifier, it can be used anywhere a high-quality attenuator is needed, whether passive or active. For example, it would make a first-rate foundation to an excellent passive line box.

Designed by John Broskie & Made in USA

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TCJ Filter Design

The Tube CAD Journal's first companion program, TCJ Filter Design lets you design a filter or crossover (passive, solid-state or tube) without having to check out thick textbooks from the library and without having to breakout the scientific calculator. This program's goal is to provide a quick and easy display not only of the frequency response, but also of the resistor and capacitor values for a passive and active filters and crossovers.

TCJ Filter Design is easy to use, but not lightweight, holding over 60 different filter topologies and up to four filter alignments:


While the program’s main concern is active filters, solid-state and tube, it also does passive filters. In fact, it can be used to calculate passive crossovers for use with speakers by entering 8 ohms as the terminating resistance. Click on the image below to see the full screen capture.

Tube crossovers are a major part of this program; both buffered and un-buffered tube based filters along with mono-polar and bipolar power supply topologies are covered. Available on a CD-ROM and a downloadable version (4 Megabytes).

Download or CD ROM
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