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The Birth of Bad
Attitude
The
Tale of the Tube
Creating
the perfect sounding amp that will satisfy a wide range of
guitarists is an art more akin to fine cooking than it is
an objective science. Our latest proprietary invention, which
I call Progressive Linkage, falls somewhere between art and
science, and satisfies a previously ignored need of guitarists.
The first example of this technology is used in our new Blue
Angel amplifier. It gives guitarists instant access to tonal
variations impossible to achieve with previous amplifier designs.
The following is exerpted from our recent patent application
for Progressive Linkage. I think that many of you will find
it interesting.
In a technical sense, one vacuum power tube works
the same as another; plate dissipation and current handling
abilities differ among a selection of power tubes, but on
paper current is current.Yet there exist enormous differences in the musical styles
created by different tube types, and these styles are immediately
detectable to most advanced guitarists. These differences
in both the dynamic feel and the sonic character impart a
unique signature that is often recognizable as the foundation
of an entire musical style.A good example of this is exemplified by the very different
signatures of the 6V6 and EL84 power tubes. Both tubes have
modest power handling capabilities of around 15 watts per
pair. Both were widely used in the 1950s and '60s, which were
the formative years of the electric guitar. And both types
have nearly identical plate characteristics. Yet their individual
musical signatures are vastly different.Sonic History The 6V6 was widely used by Fender during the '50s
and '60s for their low power models. These amplifiers were
popular with "electric blues" guitarists who often
found their amps underpowered, and simply turned them up!
Of course the amp ran out of power and distorted heavily.
But the distortion quickly became used as a further tool of
musical expression when in the right hands.Operating below the distortion threshold, the 6V6 sound is
"skinny"-not objectionably thin, but bright nevertheless
with bouncy, resilient dynamics. When overdriven, the low
order second and third harmonics rise to predominance, obscuring
the bright high frequencies and "fattening" the
sound in a way which is a trademark of American blues. When
severely overdriven, the distortion characteristic goes beyond
what is desirable, producing an inarticulate low end which
is bloated and tubby, obliterating most other frequencies
with its woofiness.Meanwhile in Europe--particularly in England-during the same
period, the EL84 was the power tube of choice in small amplifiers.
The sound of this tube is very different from that of the
6V6. The EL84 possesses a glassy brightness whose emphasis
is in frequencies higher than the bright zone of the 6V6.
The EL84's dynamic character seems less resilient and when
driven into distortion, higher order harmonics prevail, and
an aggressive, snarling bite ensues. Overdriven to extremes,
it does not suffer from low end bloatiness but retains a more
balanced spectrum with its aggressive midrange character dominating.It is no wonder that when British guitarists began turning
up their amps and "playing the blues," it sounded
quite different from the Americans they were imitating. It's
fair to say that the difference may have been less cultural
and more technical--and largely owing to the differing tube
types: American amplifiers used 6V6 or 6L6 types and the European
units (which were sometimes identical to American circuits
except for the power tubes) used EL84 and EL34 types. (The
best example of this is the fact that the "plexi"
Marshall circuit is identical to a 4x10 Fender Bassman.) Since
both of these European tube types possess a more snarling,
aggressive midrange distortion than 6V6 or 6L6 tubes, it is
easy to see how "bad attitude" rock and roll styles
such as heavy metal developed from blues-based music being
played on amps fitted with European tubes and cranked up into
heavy distortion.The Tonal Passport With Progressive Linkage, the power amplifier is
provided with a plurality of tube types and includes a switch
to select different pairs of output tubes, either alternately
or combined for simultaneous performance. The most useful,
as well as logical, choice is an amplifier which combines
6V6s with EL84s for low to moderate power (as utilized in
the Blue Angel) or one which uses 6L6s with EL34s for moderate
to high power.The single amplifier can produce the actual signature sounds
of either of the two types of tubes making genuine British
or American musical styles obtainable with true authenticity.Another feature is the selectability of output power. For
those who insist that only power amplifier distortion is acceptable
(and preamp saturation is not) the problem of correct wattage
is a major concern. Differing room size, acoustics, and the
number and type of other instruments in the band dictate a
certain power level which is appropriate. Dedicated players
are often known to bring a small fleet of different powered
amplifiers so that they have one that's right for the job.Progressive Linkage largely solves this problem by offering
three different and selectable levels of output power. The
lowest is the single pair of 6V6s at around 15 watts. The
next is the two pairs of EL84s operating alone to produce
approximately 33 watts. And the last is the combined output
oftwo 6V6s, plus four EL84s for a total capability of around
38 watts.Another advantage of Progressive Linkage is the option of
a third sonic characteristic achieved by using all tubes simultaneously.
The tone produced is refined and highly desirable, as the
likable tonal elements of each tube type seem to improve the
weaknesses of the other. The 6V6s soften the brashness of
the EL84s and add body to the lower regions. Simultaneously,
the EL84s cause the combined sound to retain tightness and
articulation while preventing objectionable low end woofiness
from taking over.
In true Mesa/Boogie fashion, the advent of Progressive Linkage
gives tonal versatility to amplifier purists, as well as creating
new signature sounds for the guitarist's vocabulary.
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