The Jim Kelley 2 Channel Line Amp
The Jim Kelley Power Attenuator
Photos
Articles
Ads
Documents
Patents
In 1978 I quit my band, sold my Alembic bass, rented shop space from
luthier Dale Fortune, and began doing business as Active Guitar Electronics
in Tustin, Califonia. Relying on my college electronics degree, years as a TV
broadcast engineer, and my experience working for Forrest White, Tommy Walker and Leo Fender at Music Man in Anaheim, I went to work doing amplifier repairs and
modifications. As a result of this work, I determined that the push-pull
output section of an amplifier produced a better sounding distortion than
did the preamp section in master volume type amplifiers. It seems
obvious now, but at the time it was a profound revelation.
Subsequently, I built a series of prototype amplifiers, and with the
tireless help of Todd Wilson from Fortune Guitars, I endeavored to
eliminate any and every detectable bad sound from the amp. This resulted in
a final design which I showed at the 1979 Winter NAMM under the Fortune
name. The basic amplifier had 6 tubes and 3 knobs. It was an electronic hot
rod, and it was small and loud. I sent one of those first 5 prototypes in a
figured mahogany cabinet to Eric Clapton out of gratitude for the profound
effect his music had on my life.
The amp was loud, and so to solve the volume control problem, I devised a variable L-pad device
capable of handling the high amount of power produced by the amplifier when
driven to full power. This provides essentially the same function as a master volume,
only the sound is much better. My Power Attenuator remains one of the best guitar amp
attenuators ever devised.
Thanks in part to Fred Walecki at Westwood Music, LA session and touring
players began to hear about the amps. These included, among others, Carl
Verheyen, Jake Hill, Mike Hamilton, Steve Farris, Richard Bredice, Bruce Boulanger,
George Johnson, Curt Eilenberg, Robben Ford, Ricci Martin, Jim Messina, Dean Farley, Billy Hinsche, Carl Wilson, Dan
Yablonka, Jerry Jeff Walker, Gary Puckett, Daryl Stuermer, Doug Freeman, Mark Kendrick, Lee Ritenour, Pat
Hennessey, Randy Thomas, Dana Olsen, Alan Holdsworth, Prince Robinson, and Ray Parker Jr.
Those are some of the people who I can recall using the amps and suggesting
features such as reverb and channel switching (obviously I've forgotten the
names of hundreds of others). By the end of 1979, the Reverb Model had
become the mainstay of our amp line and I decided to market the amps
under my own name. Initially, in order to answer the need
for switching, I added a footswitch to the power attenuators. This allowed
players to turn up the volume on their guitar for an overdriven solo tone
with the attenuator engaged, or back-off the guitar volume and bypass the
attenuator for a clean rhythm sound.
It was around this time that my dad, Stan Kelley, introduced me to record
producer Rob Fraboni. Fraboni, who worked out of Shangri La studio in Zuma
Beach, apparently loved the amps and recommended them to seemingly everyone.
Through Rob, we were introduced to a number of recording artists including
Vince Gill, Jeff Wilson, Rick Beilke, Max Gronenthal, Johnny Lee Schell,
and Bonnie Raitt - more than I can remember. The amps were used on a number of
albums recorded at Shangri La. Rob Fraboni was probably the single greatest
contributor to the success I have had in my amp building career.
By the end of 1980 we had begun exporting amps to Japan (through Hank
Hoshino), Germany (though Musik Jellinghaus), and Australia. Over the next
few years we built an elite dealer network across the US. It was through
our New York dealer, Rudy's Music Stop and John Suhr, that we were
introduced to a number of prominent East Coast artists. Among them include
Jack Sonni, Lou Reed, and Mark Knoffler (recording in New York at the time).
In the modern day, players such as Joe Bonamassa and Pete Thorn, as well as European artist
Ángel Miguel have become enthusiasts. There are undoubtedly others,
but this is the best of my knowledge and recollection.
The FACS (foot activated channel switching) amp was the result of an epiphany.
For weeks I had been considering all the various
possibilities and problems associated with a channel switching amp. The main
problem to solve was what features to provide, and more importantly
how best to incorporate them without sacrificing tone. The amp needed to be
a true advancement, not just a repackaged revision with new doo-dads. For
me there is beauty in simplicity, so I sought a simple solution. I knew that
the JK tone controls worked great for clean rhythm, and for blasting
overdrive, and that each use had unique settings. And I knew that I needed
to incorporate the power attenuator into the equation, too. Then came the
epiphany. It was in one of those rare moments of absolute clarity that I
knew I should include two independent JK preamps, each with its own tone
stack. In this way, optimal lead and rhythm eq's could be adjusted
independently. And the preamps would be switchable as channel 1 and channel
2. I would also provide a separate reverb control for each channel.
As the final piece of the puzzle, there would be an additional relay to
simultaneously switch the attenuator. That was the genesis of the FACS
amplifier.
I learned early on that unmatched output tubes would distort asymmetrically, and produce
notes that lack definition and sustain. And so from almost the beginning, I used
matched output sets. But as a consequence, the resulting matched sets would
require significantly different bias settings from one to the next. Back
then, not everyone had the luxury of a personal amp technician, and I was
concerned that the average guy might have difficulty correctly adjusting the
bias when he replaced output tubes. It was for that reason that I began
installing the LED bias indicator boards. It was a simple idea, based on
the same measurement I used to match tubes. The circuit, as implemented,
proved to be a bit too delicate in such an environment. But I think it was a
good idea in principle.
During the early 1980's, players began assembling refrigerator sized racks
of equipment as part of their guitar rigs. During this period I was commissioned
on a few occasions to build a rack mount preamp. I usually opted to stick pretty close
to my standard circuit arrangement. This was fine as long as the customer wanted simply to
obtain a clean signal from it. However I began to get requests for an overdrive capability,
and this raised the specter of the dreaded 'master volume'. However, sticking to my ideals
I resisted, and instead endeavored to create a Jim Kelley amp in miniature - at preamp level,
complete with phase splitter, push-pull output, and a line level output transformer.
The preamp must have worked well enough because I decided to incorporate the idea into
a new version of FACS amp I called the Line Amp. For this amp I devised a new tone control
that became saddled with the inglorious misnomer 'Pre-EQ'. In production it in fact became a passive,
infinitely variable, post distortion, LC mid-boost and cut EQ control. As far as I know,
it was the first of it's kind.
By 1984, interest rates had sky rocketed and the dollar became expensive on the
foreign exchange. Sales lagged and our exports all but ceased. Tom Sholtz
from Boston was making solid state headphone amplifiers that sounded like a
dimed Marshall stack, and American made tubes were fast becoming a thing of
the past. Textbooks claimed that Field Effect Transistors produced transfer
characteristics much like a pentode vacuum tube. And by this time I had determined that the
circuitry surrounding the active elements contributed perhaps even more to
the sound than the tubes and transistors themselves. So it was in this
environment that I decided to experiment with an all FET amplifier.
Although the experiment was a success, and the sound the amp produced was
exceptional, there was at that time even less interest in a transistor amp
than there was in my tube amps.
In mid 1985 I hired an auction company to liquidate the company inventory and
equipment. For six years we managed to build an average of 100 amps per year. In the
beginning I was ambitious and intensely motivated to make the best sounding, best built guitar
amplifiers. In doing so, I hoped that I might attain a good reputation.
From that I naively expected success to inevitably follow. But it was the
enjoyment of the work and the technical successes that provided me with my motivation. Eventually, for
various reasons, the enjoyment subsided and it became time to quit.
I want to thank all of my customers, employees and family, dealers,
representatives, and artists who believed in the amps and supported us back
then. It was you who gave a voice to the amps, and helped build a legacy.
Carl - I'll always regret not coming to that show, and Vince, you were the
nicest of all. To all, and especially to those I have forgotten to mention,
thank you with all my heart.
Jim Kelley
"500,000 halos outshined the mud and history. We washed and drank in God's tears of joy.
And for once, and for everyone, the truth was not still a mystery."
Jimi Hendrix
Inquiries:
jimkelleyamps@gmail.com Thanks to Ryan Reschan and Matt 'Max Harmony' Harmon for their help assembling this website
1250
Line Amp Sound Clips and YouTube Clips