This month we get an amp company’s perspective
on design and speaker selection
from Jeff Genzler, founder of Genz Benz.
Approaching new amp design involves several
criteria. Roger Hart (Product Manager),
Andy Field (Head Engineer), Scott Andres
(Head Tech) and I discuss defining the product
and ensuring acceptance in the market.
The product must fit or expand our current
line, and we focus on our target market. We
also have to review the competition and
their products.
Genz Benz offers three distinctive amplifier
products – electric, acoustic and bass.
Tonal requirements are radically different,
but the design approach is the same.
For guitar amps, we diligently focus first
on the desired tone or tone ranges we
wish to achieve. If not, a design can
morph into something else; we call this
‘mission creep’.
Our first guitar amp was the El Diablo,
a 100-watt, high gain amp. We knew
that the right combination of features,
versatility, power and build quality would
be well-received. We desired an exceptional
clean channel and the ability to punch out
heavy distortion.
The amplifier is only one part of the total
package. The speakers are critical in delivering
tone, dynamics and feel. We knew
the El Diablo would blend well with our
GB 212GFLEX cabinet, and compliment a
classic 4x12. We chose the GBE1240-V75
speaker, custom manufactured by Eminence.
I worked with them in the mid-‘90s to produce
it. It uses a British cone, a special treatment
on the cone surround, and a denser
dust cap to trim top end ‘beaminess’ typical
in similar speakers. Once we have the amp
design and desired speaker tone, we are
very conservative pairing speakers to the
amp’s power rating.
Roger Hart was a key influence on the tone
development of the Black Pearl 30. We
studied Robben Ford, Larry Carlton, Mark
Knopfler and Santana as tonal benchmarks.
We combined our features, build quality and
intrigue with EL84 power-tube tone and the
classic/vintage EL84 amps. We tested many
vintage-style amps against our development.
The classic Vox AC30 from the ‘60s
used a classic Alnico speaker and it was a
significant key to the tone. During one of
many speaker shoot-outs, all eyes and ears
pointed towards the Eminence Red Fang
12”. It delivered a depth, bell-like chime, and
touch sensitivity from the Black Pearl like no
other. We usually need to revamp speakers
before reaching our ultimate decision by
spec’ing different cones, spiders, voice coil
windings, etc., but the Red Fang was right
off-the-shelf.
We hear customers describe the Black Pearl
30’s tone in the same terms we used when
we first envisioned it. When players like
John Hiatt and Nashville studio legend Brent
Mason discover and play an amp unsolicited,
you really know you’ve created something
special. This amp is an extension of the
instrument in the guitarist’s hands. Whether
digging in with the pick or laying back on
the guitar volume, it responds to every
nuance of the player’s style and technique.
The amp uses a passive EQ. On many
passive EQs, increasing one filter control
shifts and changes other frequencies, making
incremental changes challenging. The
Black Pearl EQ is not as interactive, adjusting
each tone control only adjusts that specific
filter. When you crank the all-important mid
frequencies, the BP 30 almost has an additional
gain stage!
Blues players have always asked me about
a 4x10 guitar cab, and I realized the Black
Pearl was the right platform for multiple
10” Alnico speakers. We reviewed current
brand options for 10” Alnicos. The tone and
response were ‘underwhelming’ even in the
models used in many vintage-style amps.
I knew if we got the punch and throat of
the 12” Red Fang into a 10”, it would set our
amp apart. Eminence helped us combine
the 12” Red Fang motor structure with a 10”
cone. After a few tweaks, we achieved
the new Eminence Red Fang 10 for our
Black Pearl 30, 3x10 combo and 4x10
cabinets.
We chose a 3x10 configuration for a
few important reasons. Placing speakers
closely in a single air space always
intrigued me. We found that a tight triangular
layout produced a focused punch.
The coupling of the sensitivity of three
speakers gives the Black Pearl a huge
tonal footprint and killer 30-watt combo
tone. The response from this configuration is
punchy and articulate with a vocal midrange
presence, maintaining the pristine chime
we enjoy from the Eminence Alnico driver.
When cranked, the amp is all classic rock,
drive, and muscle – think AC/DC, vintage
British rock. We also kept cabinet size and
weight at a minimum.
For more details on the El Diablo 100, the
Black Pearl and other Genz Benz products
please visit Genz Benz at genzbenz.com.
Anthony “Big Tony” Lucas
is a guitarist and Senior Lab Technician at Eminence
Speaker LLC, where he specializes in guitar-speaker
design and customer support. Big Tony has been with
Eminence for over 10 years and is responsible for many
well-known guitar speaker designs.