- Jurich, E. J.
Vacuum Tube Amplifier Basics.
2nd. ed.
Seattle: Amazon Digital Services, 2013.
ASIN B00C0BMTGU.
-
If you can get past the sloppy copy-editing and production values,
this book is a useful introduction for those interested in designing
and building their own vacuum tube audio equipment. Millennials
and others who have only ever listened to compressed audio will
wonder why anybody would want to use such an antiquated technology,
but those of us who appreciate it have a simple answer: it sounds
better. The reason for this is simple once you poke through the
mysticism surrounding the topic. It is in the nature of audio that
peaks in the signal are much higher than the mean value. Solid-state
amplifiers tend to be linear up until some signal level, but then
“clip”—truncating
the signal into a square top,
introducing odd harmonics which the human ear finds
distasteful. Tube amplifiers, on the other hand, tend to round off
transients which exceed their capacity, introducing mostly second
harmonic distortion which the ear and brain deem “mellow”.
“Do you actually believe that?”, the silicon
purity police shriek. Well, as a matter of fact, I do, and I currently
use a 40 watt per channel tube amplifier I
built from a kit more than
a decade ago. It's a classic
ultra-linear
design using EL34
output tubes, and it sounds much better than the 200 watt per
channel solid-state amplifier it replaced (after the silicon went
up in smoke).
This book will introduce you to vacuum tube circuitry, and those
accustomed to solid-state designs may be amazed at how few components
are needed to get the job done. Since every component in the signal path
has the potential to degrade its fidelity, the simplicity of vacuum tube
designs is one of the advantages that recommend them. A variety of worked-out
vacuum tube designs are presented, either to be built by the hobbyist or
as starting points for original designs, and detailed specifications are
presented for tubes widely used in audio gear.
The production quality is what we've sadly come to expect for inexpensive
Kindle-only books. I noted more than 40 typographical errors (many
involving the humble
apostrophe),
and in the tube data at the end, information which was clearly
intended to be set in columns is just run together.
This book is available only in electronic form for the Kindle
as cited above, under the given ASIN. No ISBN has been assigned
to it.
August 2013 