As promised, I will reflect on the Blencowe book once I have it and compare it with the Londonpower series.
I bought the "Designing Valve Preamps for Guitar and Bass, Second Edition"
book. I did not scrutinize every page, but went through the tokes rapidly, because most of them were familiar (but not all). (Note: I do not want to create the impression that all of this
has gone to my flesh and bone
First thing that springs to mind, the Blencowe books are much smaller in format, for those who seek a buck per paper weight benchmark.
Blencowe has a more academic approach, there are pages and pages of how to do calculations for correct biasing and load lines, which will suit those who want to build an amp from scratch rather than using proven schematics (this is not to say that those schematics are always the best. Many of those are influenced by financial considerations rather than sensical engineering...)
Many of the subjects are just touched upon, whereas O´Connor really goes into them. Example1: signal switching
Blencowe just tells the basics while O´Connor spends pages and pages on different solid state methods, different practical
transistor circuits and methods he incorporates in his line of amplifiers.Example2: DC Heater
Blencowe a small chapter to this subject, wheras O´Connor goes into all the pro´s and con´s and different practical circuits.
Blencowe does not excurse into contemporary solid state electronics, whereas this is an essential part in O´Connors amps, where it does not contribute to or distract from tone. I was able to apply many of those concepts to modern stomp box devices. There is a huge amount of information in those books on MOSFET circuits, solid state current mirrors and the like.
Blencowe does nevertheless strike upon a few subjects that I cannot recall reading in the O´Connor books, such as avoiding the forward gate current choking in Fender amps if they are overdriven.
In short, those books are not really in conflict with another. Neither do they cover the same information.
They nicely complement each other.
If I were interested in the basics of tube operation and all the math around it, I would like the Blencowe book.
If I were new to modifying a given tube amp, I would probably be better off having the O´Connor series of books, at least the two volumes I mentioned earlier in this thread. For the high price claim, there is much more information contained in the londonpower books, so you get more, you pay more.
Be aware however of the later volumes though. Some of those are dedictated to the powerscaling technology, which might not be everybody´s taste, and one is entirely full of commercially successful amp schematics with associated improvements which may only be of interest to somebody who wants to build one of those or owns one of those.
With the O´Connor series of books I felt quite empowered to start modifying a given architecture, with the Blencowe book I probably would not. Again: I am strictly speaking of the above mentioned book.
Both series of books seem to be written with care to detail. Both are of much greater use to builders that other books I have, whose authors
left the impression that they want to endorse their line of amps and create the question whether they want to boost their tube sales or egos.
They usually just reprint a couple of popular schematics with their doubtful mods and improvements
so you sort them out soon.
One thing I particularly like as a teacher and circuit develovper about the O´Connor series of books it his approach to a good technical solution.
He usually starts off with an intuitive circuit, which then gets refined in several stages until a well working contemporary circuit is there.
Sometimes he is a bit hasty there in the rush, so you are left scratching your head upon a step he makes. Usually those things are easily resolved
in an e-mail, unless you have worn out your welcome like I did, probably with a small setback for the ego due to an uncautious remark
I hope this helps somebody.