Mesa/Boogie Mark 5, Owner'S Manual, Page: 46 / 70

SWITCHABLE RECTIFIERS: 45 WATT POWER MODE
Switchable Rectifiers makes its debut on the MARK Series for the first
time here on the FIVE in the form of patented Rectifier Tracking™. Channels 1 and 2 are fitted with individual mini toggles (located
under the Channel 1 and 2 REVERB Controls) that allow you to choose between the tight, bold, higher-headroom
response of Silicon DIODES or the saggy, sweet, low-output looseness of TUBES (Tube Rectifier) in the 45 Watt Power
Mode. Channel 3 utilizes Silicon Diodes all the time as the amplifier circuits it contains all used Silicon Diodes.
The Simul-Class
™
90 Watt Power Mode automatically selects the big power punch of the Silicon Diodes and the
Single Ended, Class A 10 Watt setting requires the Tube Rectifier to operate safely. The rectifier circuit converts
the incoming A.C. voltage to D.C. for the tubes to run on and the type of rectification has a big impact on the sound and feel of the
amplifier.
DIODES deliver the maximum headroom, attack and dynamic content and track tighter – especially in the bass region. Diodes work
great for clean chording sounds in Channel 1 and tight-tracking crunch rhythm sounds in Channels 2 and 3. Lead sounds will be
more explosive and focused and deliver the greatest articulation.
TUBE
slows things down, reduces headroom, smooths things out and scoops upper midrange along with producing a more elastic,
bouncy feel on the strings. Tube rectification is great for threshold of distortion sounds on rhythm parts and vintage style single note
soloing. TUBE also re-voices the top end raising it up an octave and making it a little recessive at the same time.
CHANNEL 3: TRIODE / PENTODE
A PENTODE / TRIODE mini toggle switch (located just under the CH 3 REVERB Control)
allows you to choose the wiring configuration of the middle pair of power tubes in Channel 3 only. This is a feature that
was popular on the MARK 4 and changes the personality of the attack and liquidity of the sound in the higher gain condi-
tion found in Channel 3.
This switch re-wires the configuration of the Class A pair of output tubes (inside two 6L6’s) to produce a radical sound and
feel difference in the Modes (only in Channel 3). We have found many players like it only one way – citing that it makes or
breaks the vibe for them or that they can’t play as well when it’s not set to their favorite way. We feel it is a powerful stylistic parameter
and should be explored fully for its usefulness to your sound.
TRIODE softens the midrange attack and accentuates the upper harmonic region creating a silky, more compressed - almost liquid
feel - and lowers overall power output. This setting tends to raise the harmonic haze and sweeten the top end and it shines for ex-
pressive high gain solo work or high gain chording that is more textural than rhythmic. It offers more complexity and nuance, but the
trade-off is that it may not cut through a mix as well. TRIODE produces less overall power output so it is probably not the choice for
very low gain chording unless you are looking for more of a “vintage sag” feel. All original MARK II-C+ amplifiers were hard-wired to
TRIODE whereas the MARK IV offered a choice between these two configurations.
PENTODE accentuates midrange punch and lowers the upper harmonic region for a bolder, tighter attack – especially in the low end
– and increases output power and headroom. PENTODE delivers a much more immediate dynamics with greater peaks and feels
“faster” to play… almost anticipating your next input. This urgent attack means that PENTODE excels at any style where rhythmic
nuance and tight-tracking accuracy are essential. This is probably the best choice for solo sounds that pop through a mix and high
gain crunch chording that is defined and articulate with huge tight low-end.
rear panel: f
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