errors in The Ultimate Tone by K. O'Connor

[Randall]

I am studying Vol 3, and I find some errors. For example, in the Portaflex chapter he gets the 2K2 and 5K6 preamp cathode resistors reversed multiple times in one section, and then opposite later on. Also, I have seen a couple of times where he denotes caps in N where they are uF, as in the output tubes electrolytic cathode bypass cap. He has it as 50N, it is actually 50uF/50v.

Makes me wonder what else is wrong? I see these as reference text books to learn from, aren't these proofread? They cost enough.

[bob p]

I don't have any of his books, so I can't answer your question directly. What I can say though, is that I've had several interactions with him on the forum where I thought his assertions were dead wrong from an engineering perspective. I don't think that's all that significant really, as it's not at all uncommon for people to have disagreements on things, and everyone makes mistakes. There've been plenty of times when I've had my idiot-hat on, so I can't blame anyone else when it happens to them.

I seem to recall a point in time where the Power Scaling implementation put high voltage DC on the front panel pots, which I thought was an irresponsible and dangerous design. My memory is a bit foggy on that discussion, but I think that design has subsequently been revised to make it more safe to the user.

Regarding his amp designs, I also disagreed with some of the transformer choices that he made in some of his amp recommendations, but I don't think that's at all significant. Around here we spend a lot of time debating one transformer vs. another for almost every application.

The biggest reason that I don't own any of his books is that I prefer to read vintage books from the golden era. That, and I think that the hand-scribbled illustrations that I've seen excerpted from the TUT series were substandard in quality in relation to the price that he's asking for the books. I think that anyone who charges as much as he does for his books should put more effort into the graphics -- especially in this day and age when software to draw schematics is so widely available that just about any post you'll find on the internet will have a better looking image than one of his books. Maybe I'm just funny that way, but picture quality gives me a general bias about overall quality of the work, and crappy illustrations are a definite turn-off for me.

I've also heard other people complain about mistakes and a lack of proofreading, so maybe you're on to something.

Rumor has it that if we mention his name three times in this thread, he'll appear in the conversation and correct our misteaks.

Have you looked at any of Merlin's books?

[Tom Phillips]

...Have you looked at any of Merlin's books?

I really like Merlin's books. I have purchased them all as soon as each became available. Note that they all have typos especially the first two. Still well worth the cost but a reader still needs to be alert and question / verify information no matter what the source.

[Enzo]

And ther is a difference between mistakes and disagreements. We might disagree with kevin that bypassing some resistor is good, but if the drawing say 500k when he meant 500 ohms, that is a mistake, not a disagreement.

Why not carefully log the errors you found and contact Kevin at London power and politely point them out. Any author wants to know about errata.

[Randall]

I just realized what I took to be an "N" on the electrolytics, is actually some other symbol he uses for uF. He is consistent with it. I guess it's just a sloppy rendition of the proper symbol, and it is hard to see because it is all handwritten.

[Enzo]

That is a "mu", the greek letter, which is really more accurate than an English "u". it is a lower case mu, upper case mu is just M.

We use u for microfarads because it is the closest looking letter on a typewriter to the Greek mu. mu is short for micro. If I write us, we understand it means microseconds. But I really should get motivated to type mu-s.

https://en.wikipedia.org/wiki/Greek_...nd_engineering

[MarkusBass]

What you take for the letter "N" is simply the greek letter "µ", which stands for "microfarads" so I don't see any mistake here. This is a common way of marking that a capacity is in microfarads. In the same way there is "n" for nanofarads and "k" for kilo-ohms. I'm surprised that you are surprised by this marking.
But you are right that the quality of the hand-drawn schematics is so bad that I would expect a little bit more (I also have the book and noticed the problem). Especially, that you can draw beautiful schematics with free tools (like e.g. Inkscape).

Mark

[g1]

When Kevin first started bringing his books around, we didn't even have netscape yet, never mind inkscape.
Windows 95 was just starting to show up.

[Randall]

I was familiar with the symbol, I just wasn't recognizing it in it's sloppy form. Even now that I understand what is going on, it still looks more like an N to me.

I was looking over his take on the Garnett Herzog, and went off on a tangent looking for the PT he discusses that has a center tapped plate voltage of 230v. After some searching, I took a look at the original drawing, and it is actually 320v, so yeah, lots of oversight here.

[bob p]

It's time to get up to date with the 1940s.

International System of Units

What you take for the letter "N" is simply the greek letter "µ", which stands for "microfarads" so I don't see any mistake here...

To be fair, the official SI abbreviation "µ" is a dimensionless numeric prefix. It does NOT mean "micro-farads", even though we think of it in that context when we read schematics and see a capacitor symbol, just as we assume that "k" or "K" next to a resistor means "kilo-ohms" when the reality is that "k" means only "kilo" and "K" means only "Kelvin".

You might also run into some older schematics that show double metric prefixes, which have officially been abandoned, effective when the old metric system was officially replaced with International System of Units (SI). You might notice old schematics that say "µµF", for example, which is an obsolete expression of "micro-micro-farads". The proper abbreviation is "pF" for "pico-farads." There are a lot of old American schematics that still used the common American abbreviations in the 1950s-1960s because old habits are hard to break.

By the time I took physics in the 1970s all of those old abbreviations had been cast along the wayside and everything was being taught in SI units. That was 4-5 decades ago. Failure to use the proper SI abbreviations when writing theory books today makes it unnecessarily difficult for readers to learn from a reliable source that is consistent with the rest of the world's nomenclature. The SI was officially introduced by the International Union for Pure and Applied Physics (IUPAP) in 1948 and was adopted almost everywhere by the 1960s. Anyone who is writing textbooks and is still using the obsoleted prefixes needs to get with the program.

[Enzo]

kevin abbreviated it, we would normally add the units - uf even sometimes ufd.


I still write cps instead of Hz sometimes.

[MarkusBass]

I didn't write that "µ" means "micro-farads". I wrote that "µ" stands for "microfarads" (on schematics), which is not the same (at least for me). This is an agreement between the person who created a schematic and a person that reads the schematic allowing the reader to understand it (and reproduce if needed). The reason why you don't write "µF", or "µ-farad" is very simple - it will not fit - especially on complex schematics.
So I still don't see any problem here. What Randall takes for "N" is hand-written "µ". It shouldn't be written so poorly by I can easily recognize the symbol. Just look at "22n" and you will understand.

EDIT: I've just check few schematics from Fender (e.g. FM65). They use a different type of "agreement" between them and the reader. Electrolytic capacitors like 22uF are marked on the schematic simply as "22" - without any symbol. Capacitors in nanofarads range are marked as .033 - again without any additional letter. it's a reader responsibility to guess what are actual values. So you must be familiar with such special ways of marking components on schematics.

Mark

[Dave H]

The reason why you don't write "µF", or "µ-farad" is very simple - it will not fit - especially on complex schematics.

At the company where I worked we didn't use decimal points or leading or trailing zeros. You didn't write .0033uF or 3300pF you wrote 3n3 It takes up less room and the decimal point can't get 'lost'

[Enzo]

Mark - on many if not most Fender schematics and many others, in the notes will be something like "all capacitances are in microfarads unless otherwise noted". So you see your 22 and 0.033, and I bet if you look closer the bright cap will say 120pf, to indicate there is a different unit than uf. The reader is not left to guess, the reader is expected to read the notes. I do agree that the less clutter on a drawing the better, so a note like "all resistors 1/2 watt 10% unless otherwise noted" are better than writing 1/2w next to the value at each part. Just as we use a symbol for ground or B+ instead of drawing "wires" from the power supply to each point in the circuit.


Using the units in place of decimal is a relatively recent thing. I don't know where it started to become popular, but in my mind it was a euro-thing. I like it, but never use it, simply because I have been doing it the other way for 60 years. And growing up, we used ufs and uufs (pf). Nanofarads existed on paper, but we never saw them. 0.022uf rather than 22nf. I have come around to using picofarad naturally. But for me, nanofarad only gets used when I actively think about it for style. So 1k5 I think is better than 1.5k, but there is a lot of inertia in changing.

WHy adopt nano farads if I don't also adopt millifarads. Anyone ever write 1mf in place of 1000uf? I sure don't.

[Pedro Vecino]

At the company where I worked we didn't use decimal points or leading or trailing zeros. You didn't write .0033uF or 3300pF you wrote 3n3 It takes up less room and the decimal point can't get 'lost'

Such measures (3n3, 4n7, etc.), as I understand it, correspond to a European system of nomenclature. In electrolytic capacitors it is usually 3u3, 4u7, etc.