-
The following article is presented here with permission of the
editor of The Guitar Magazine, Dave Hunter -
The Guitar Magazine is a British publication
From
The Guitar Magazine, May 2000, vol 10 no 10
Amp
Tech:
BY THE
BOOK
Since the
introduction of our Amp Tech column a year ago, TGM
has taken you through a variety of basic maintenance jobs and some
more adventurous mods and DIY projects, all - so far - in fairly
basic join-the-dots style. But where do you go if you want to
learn to understand your amp from the inside out but don't have
time to enrol in a diploma course in electronic engineering? For
starters, you can go a long way with a spate of good old-fashioned
book-learning - particularly if you're willing to burn a little
midnight oil absorbing the wealth of information in some of the
more technically involved books available, such as those written
by amp guru Kevin O'Connor and published by Canada's Power Press
Publishing, a division of London Power Guitar Systems (we're
talking London, Ontario here).
All five
books in the series are printed in the same spiral bound,
8.5" x 11" (North America's near-equivalent to A4),
black-and-white-only format, with rudimentary coloured card format
front and back covers overlaid with protective clear polythene.
Diagrams are entirely hand drawn (though never less than entirely
clear for it), printing is lo-fi, there's no eye candy in the way
of juicy colour pics ... it's all very evening-course-text-book
circa 1973.
And therein
lies a clue to their worth: each of these publications is
absolutely dripping with detailed, broad-ranging
information. The basic format only further affirms that this is a
real behind-the-scenes, for-your-eyes-only type peek into the
world of one of North America's most respected amp designers.
They're densely packed, unadorned, occasionally text-heavy - but
devote some time and effort and you could come out with serious
tech-head pretensions. But be warned: they're not for those with
limited attention spans.
Conveniently,
as well as addressing somewhat different subjects, the books are
grouped into levels of difficulty. We'll start by examining the
less involved and work our way upwards.
SITTING A-LEVELS
Intermediate
level projects (there's nothing here for the absolute beginner,
though if you can handle a soldering iron and a multimeter you can
jump in here) are covered in Tonnes of
Tone: Electronic Projects for Guitar and Bass (105
pages, ISBN 0-9698-6082-X). With thorough explanations of
principles along the way, O'Connor's projects here range from
building 'bench necessities' like a safety socket and
experimenter's power supply to simple active and passive acoustic
preamps to more involved DIY adventures such as all-valve guitar
and bass preamps, power amps, a solid state tremolo circuit and
even a tube reverb.
With all of
the above, component layout diagrams as well as circuit schematics
give you all the information you need to know for successful
building, while thorough parts list (with specific manufacturer's
part code number for larger items like transformers and chassis)
show you at a glance what needs to go into the shopping cart.
The real
bonus, however, is the attention to construction detail. Rather
than just throwing the electronic know-how at you and jumping ship
like some other 'musicians' projects' books do, O'Connor provides
thorough grounding in cutting, bending and drilling sheet metal
(for chassis building); woodworking (for amp cabinets); and even
painting, lettering and covering for cosmetic completion of the
job. All fantastic stuff, and presented with an enthusiasm
guaranteed to get you itching to build.
Taking us
even further into textbook territory is Ready
Set Go! An Electronics Reference for the Everyman
(82 pages, ISBN 0-9698-6085-4). A sort of 'electronics foundation
course' in print, this book is aimed equally at the radio, audio
or even computer electronics enthusiast, but makes a great
springboard for the musician wanting to understand electronics
principles from the ground up. Covering anything from units and
symbols and reading schematics, to the fundamentals of resistance
and capacitance, AC and DC power and more, it's far more
theoretical than hands-on, but a great guide for those who want to
get serious (and don't mind a somewhat dry, technical start). Also
makes a great desk-top reference manual for any ongoing hobbyist
workbench.
DEGREE COURSE
Getting the
hands firmly back on, The Ultimate
Tone: Modifying and Custom Building Tube Guitar Amps (368
pages, ISBN 0-9698-6080-3) is the big boy in the Power Press
arsenal. This is by far the most thorough DIY-style guide to
guitar amp design and modification that I have ever encountered -
there's more here than a lot of hobbyists could build in a
lifetime of spare evenings and Sunday afternoons. Without room for
basic construction techniques (covered in Tonnes of Tone -
they make a great pair) TUT jumps right in with highly
detailed, point-by-point analysis and instruction on everything
from pre- to power amp, with a fair wodge of what comes before,
between, and after.
Chapters in
this volume include thorough coverage of power supplies, vacuum
tube history and design, preamp basics and mods, power amp
designs, effects loops, reverbs, switching methods and more. Just
within 'Preamp Mods', for example, lurk sections on mods for
Fender amps, mods for Marshall amps, original London Power
designs, and some nifty bits called 'Tweed Mixer', 'Poor Man's
Overdrive' and 'Traditional Overdrive Architecture'. Cool!
Beyond just
presenting diagrams and schematics, The Ultimate Tone delves into
a degree of theory to back up all subjects addressed (the
mechanics involved in a number of different methods for achieving
preamp gain, for example), and strives to help you understand the
elements of amplified guitar sound from the ground up. Elements of
the theoretical can fly above the head of the layman - as when an
otherwise practical discussion on switching methods ascends into
rocket-science-like mathematical equations - but the un-teched
musician should still glean plenty from each topic. Appendices on
valve types and characteristics, transformer designs and more
further round out the package. If you're serious about
from-scratch amp building and major modification, this is a
must-have book.
The
Ultimate Tone Vol. 2: Systems Approach to Stage Sound Nirvana
(262 pages, ISBN 0-9698-6083-8) - nirvana as in the 'ecstatic
state of blessedness', not the band - takes a lateral leap
sideways from Vol. 1 by addressing, as the title indicates, ways
of achieving great sound on stage. In addition, it moves on to
delve even deeper into the mechanics of guitar preamp and power
amp tweaking, as well as taking on EQ, speaker selection,
compressors and other potential elements of the big-gig rig.
Jumping
from stage set-ups, PAs and monitor applications back to internal
amplifier alterations, topics here seem to flow a little less
logically (much as if it's a net to catch up the chapters O'Connor
had left over after compressing the other volumes), but it's no
less valuable for that, and still packed with a wealth of
practical information and plenty of original thinking.
POWER
RANGER
Principles
of Power: A Practical Guide to Tube Power Amplifier Design
(221 pages, ISBN 0-9698-6081-1) is a thorough discourse on
the whys of valve amp design that back up all the hows
you can study in the above 'project' volumes. Intensely academic,
abundant in theory, this volume is more than many hobbyist
guitarists will need - or want - to know, but if you feel ready
for a glimpse of the dark world of the creator, it's powerful
stuff. Heavy-going out of necessity, it takes in the design
principles of power supplies, power amps, transformers, hybrid
amps and of course valves themselves. The massive 'Design Pool'
chapter alone gives generic designs for 12 different valve amps
from 12W to 280W, all using the popular Hammond output
transformers with a variety of tube complements. Highly
analytical, it's still admirably approachable considering the
ground it covers - but by its very nature Principles of Power
is likely to be less appealing to musicians than either of the
three 'project' volumes.
All told,
Kevin O'Connor has assembled the most comprehensive set of project
and theory books on amplification and tone-crafting available to
the DIY-minded guitarist. Not many of the un-trained among us are
likely to want the entire set right off - but if you're even
considering getting into valve amp building, re-building or
modification, there's a volume or two here at least that I'd
consider indispensable.
©
2000, IPC Music & Sport Publishing Ltd.