and They Will Come
The author’s amp after soldering. Dropping it into a cabinet like this is not a good idea. Extra slack and unsecured wires in the wrong places contribute to hum.
Digging in on day one of the seminar.
Bruce says most of his students come in
with minimal soldering experience, but
that rarely matters – people pick it up fairly
quickly. The group of eight I was part of
came in fairly proficient with the iron.
It was a diverse group, ranging from a
blues-playing hobbyist in his fifties to a
proud eighties hair metal fan who, believe
it or not, was only in his twenties. One
guy’s $1600 tuition was a birthday gift from
his wife. Another was getting back into
music after taking years off when his first
child was born. Students drove and flew in
from Pennsylvania, Utah and many points
in-between.
After a few minutes of introductions and
pastries, Bruce addressed the question
that I had come to answer right away. “I
have nothing to hide,” he told us. “I simply
enjoy passing along what I’ve learned.”
Each person’s workstation had a soldering
iron, an amp chassis, a schematic, bags of
components and a turret board with some
parts already soldered in. Before we knew
it, we were bolting transformers into our
otherwise empty chassis. Within minutes
the unmistakable aroma of tin/lead alloy
filled the room as we melted it within a
maze of wires, pots, caps and tube mounts.
The build was based on a JTM-45-inspired
Mojo kit but souped up with a few JCM-style touches and, of course, many custom
Egnater mods. There were some nice surprises, like the cathode follower – a circuit
where the output is taken from the cathode
instead of the plate, making it easier to
drive the tone controls while creating killer
harmonics when overloaded – and a choke,
which filters some of the DC hum before
the juice hits the screen grids.
We followed the schematics as Bruce and
his staff explained what we were doing for
eight solid hours – even longer for those
of us who weren’t technically inclined to
begin with. As each person finished up,
Bruce went through their amp and tidied
things, correcting mistakes like the red and
green wires that my slightly colorblind eyes
misread on the schematic, rerouting connections under something instead of over
it, or even resoldering buzz-prone areas like
pot grounds.
Our moments of truth came during a final
check. Every circuit was tested with a
voltmeter, which ferreted out additional
problems that some of us had to correct.
Tubes were matched and biased. Bruce also
showed us how to read a scope and plot
output signals.
