Recently, some builders have become so defensive of their oh-so-original implementation of this century-old technology that they've taken to encasing their circuits in blocks of opaque epoxy! Well, that will certainly facilitate efficient maintenance!
Coming as I do from the world of software development, I take precisely the opposite view, and choose to embrace the 'Open Source' approach to intellectual property.
In production and development, open source as a philosophy promotes
a) universal access via free license to a product's design or blueprint, and
b) universal redistribution of that design or blueprint, including subsequent improvements to it by anyone.
In the area of software development, opening the source code enabled a self-enhancing diversity of production models, communication paths, and interactive communities. The open-source software movement arose to clarify the environment that the new copyright, licensing, domain, and consumer issues created.
As commonly used, the term 'open source' refers to a computer program in which the source code is available to the general public for use and/or modification from its original design. Open source code is typically created as a collaborative effort in which programmers improve upon the code and share the changes within the community.
Open source sprouted in the technological community as a response to proprietary software owned by corporations. The open-source model includes the concept of concurrent yet different agendas and differing approaches in production, in contrast with more centralized models of development such as those typically used in commercial software companies.
A main principle and practice of open-source software development is peer production by bartering and collaboration, with the end-product, source-material, "blueprints", and documentation available at no cost to the public. This model is also used for the development of open-source-appropriate technologies, solar photovoltaic technology, open-source drug discovery, and in this instance, open-source circuit design.
Why is the Linux operating system (and its offshoot, Android) overtaking propriatary platoforms like Microsoft Windows™ in popularity? the answer, largely, is that it's an open box. There are no hidden secrets (and vulnerabilities) conveniently covered over in Linux. As a result, if a problem does arise, anyone with the requisite skill set can fix, extend, or improve it.
Have At It!
The way I look at it, anyone who thinks they're going to take my schematic and build themselves a product of equal quality at a fraction of the cost, I say: "Hey, go for it!"
In all honesty, that's precisely how I started out: I had some notion that I was going to turn a $99 Crate V18-112 into a $40k Overdrive Special for the cost of a handful of components...
...Four years later, when I finally completed my first reliable working amp, I had invested in excess of 10,000 hours and right around $6,000...
Was it worth it? Unequivocally yes! I can honestly say that I would pay that price for what I have without a second thought, and as for the hours, I learned more in those past 4 years than the time I spent in college earning my degrees. More to the point, however, the end result was not a clone of anything else out there, and while, to my ears, my amps sound as good or better than any I've heard, I don't see myself putting anyone else out of business, nor would that be my goal. It's very much like the practice of martial arts: You may start out wanting to kick ass, but if you stick with it long enough to become competent, you find the domain populated with respected peers, rather than adversaries.
Every user/maintenance manual included with each of my amps will not only contain complete, detailed schematics and board layouts, but will also include the calculations and thought process that went into selecting key component values. I really don't want anyone to ever look at my work and wonder: "What the hell was he thinking?!?!" In practical terms, it also means that anyone who decides that they want just a little more bass, or a little less drive, or a bit more headroom, or whatever, will know precisely where they're starting and how to get where they want to be. Good as I believe they are, I'm under no illusion that my designs might never be improved upon by others more talented than myself.
Moreover, in an analog to 'self documenting code' in software development, my boards are annotated with the essential circuit information:
This means that wherever in the world you might be, any qualified tech will be able to quickly and easily service my amps, at far lower cost than virtually any other equipment.
At the risk of sounding hopelessly egotistical, I do aspire to build for the ages!