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USA IIC+ / IIC++: based on MESA/Boogie Mark IIC+
MESA/Boogie is a famous amp manufacturer, founded by Randall Smith in ‘71 in California. Company information.
Some of the amps carry the MESA name while others have a MESA/Boogie label.
Randal Smith started off with the “snakeskin” Boogie amp, a modded Fender Princeton with increased gain and sustain, which made Santana famous (or was it the other way around?), now known as Mark I. It was recently re-issued.
The series has evolved. No longer called Boogie, they’re now referred to as the Mark series. Mainly known for their smooth high-gain tones, loved by metalheads as well as fusion guitar players. John Petrucci (Dream Theater) is probably their most famous endorser. Metallica are also known for their use of the IIC+. The current Mark model is the Mark Five.
Cliff:
"I have a Mark IIC+, a Mark IV, a Mark V and a Triaxis. They're all completely different. Mesa always says things like "sounds the same as a IIC+" but the circuits are different and, probably most important, the knob tapers are completely different."
"I have a Mark IIC+, a Mark IV, a Mark V and a Triaxis. They're all completely different. Mesa always says things like "sounds the same as a IIC+" but the circuits are different and, probably most important, the knob tapers are completely different."
We’ve got models of the legendary Mark IIC+, IIC++, and IV. This post is about the IIC+, the amp that introduced guitar players to liquid and smooth lead tones, and scooped high-gain.
MESA:
"And YES… it’s a MARK IIC+! A next generation Re-Issue of the legendary amp so many Recording Artists, MESA enthusiasts and Tone Freaks the world over covet, often searching high and low to find."
"And YES… it’s a MARK IIC+! A next generation Re-Issue of the legendary amp so many Recording Artists, MESA enthusiasts and Tone Freaks the world over covet, often searching high and low to find."
The quote above refers to the JP-2C, John Petrucci’s signature amp, demonstrating that the Mark IIC+ still is king of the hill.
Wikipedia:
"The Mark IIC also featured a new Pull Bass shift on the front panel, which slightly extended the low frequencies in the preamp.
"The Mark IIC also featured a new Pull Bass shift on the front panel, which slightly extended the low frequencies in the preamp.
The Mark IIC+ was the last of the Mark II series and featured a more sensitive lead channel, because it features a dual cascading drive stage, whereas the IIA and IIB had a single stage drive circuit.
Some owners/dealers/sellers say the "+" refers to an amp having an EQ, but they are mistaken. The mistake may have originated in the mid 1980s, when Mesa/Boogie issued their Studio .22 model and then changed the name to Studio .22+, which featured improved wiring, etc. All the Mark II models could be made with EQ as an option, but not all of them did. A Mark IIC+ could, for example, refer to a 100 watt amp without EQ or reverb.
One can tell if a particular amp is a "+" by looking for a hand-written black "+" mark directly above where the power cord attaches to the back of the amp. Many dealers increase the price on a Mark IIC+ but often don't know anything about what the "+" means--they often don't even know where to find the "+" mark. Indeed, the mark itself can be forged. An owner can call Mesa/Boogie and ask them to check his or her serial number against their records. Mesa/Boogie only made about 1,400 Mark IIC amps before going to the Mark IIC+. Another cosmetic way of distinguishing a IIC from a IIC+ is the front panel. A IIC has the traditional "Gain Boost" pull switch integrated into the master volume, while a IIC+ replaced the switch with a Pull Deep bass booster.
The Mark IIC+ Is currently the most coveted vintage Boogie, selling for twice its original price on average, because of its much praised "Liquid Lead" mode, and also, its warm, clean rhythm mode.”
Review in Vintage Guitar.
The modeled IIC+ is a version WITHOUT a graphic EQ. Don’t cry, see post #2. Unlike the original amp, you can use the GEQ in the models.
The original amp operates in Class-A (2 power tubes) or Simul-Class (2 power tubes in Class-A and the other two in Class A/B). It has been modeled in Simul-Class mode.
Cliff:
"If you want the sound of the non-SimulClass version set Triode 1 Plate Freq to 1350 Hz."
"If you want the sound of the non-SimulClass version set Triode 1 Plate Freq to 1350 Hz."
It has a single input, 6L6 power tubes, reverb and 2 channels: Rhythm and Lead.
The main controls are Volume (pull: Bright), Treble (pull: Shift = Fat), Bass (pull: Shift), Middle, Presence, Master rhythm (pull: Deep), Lead Drive and Master Lead (pull: Bright).
Cliff:
"The Pull Bright on the Volume knob is the classic "Bright Cap" which engages a capacitor across the potentiometer. This is already modeled in the Axe-Fx via the Bright Switch. The Pull Bright on the Lead Master knob engages a 0.22uF cap on the cathode of the last triode in the overdrive circuit. As there is no switch for this in the Axe-Fx it requires a separate model. Cathode caps are very common in tube amps. If the value is large the stage has more gain and the response is relatively flat. If the value is small the stage has more gain at higher frequencies. Amp designers use cathode caps to shape the frequency response. Caps in the range of 0.1 to 1.0 uF are commonly used to reduce bass response. A cathode cap works by decreasing the amount of negative feedback through shunting higher frequencies to ground. This reduced negative feedback increases the gain (and reduces linearity). FWIW the Axe-Fx is the only modeler of which I'm aware that actually models triodes using a feedback technique. Other modelers use static waveshapers. The Axe-Fx triode models incorporate feedback so if there is a virtual cathode cap the stage is less linear in addition to having more gain."
"The Pull Bright on the Volume knob is the classic "Bright Cap" which engages a capacitor across the potentiometer. This is already modeled in the Axe-Fx via the Bright Switch. The Pull Bright on the Lead Master knob engages a 0.22uF cap on the cathode of the last triode in the overdrive circuit. As there is no switch for this in the Axe-Fx it requires a separate model. Cathode caps are very common in tube amps. If the value is large the stage has more gain and the response is relatively flat. If the value is small the stage has more gain at higher frequencies. Amp designers use cathode caps to shape the frequency response. Caps in the range of 0.1 to 1.0 uF are commonly used to reduce bass response. A cathode cap works by decreasing the amount of negative feedback through shunting higher frequencies to ground. This reduced negative feedback increases the gain (and reduces linearity). FWIW the Axe-Fx is the only modeler of which I'm aware that actually models triodes using a feedback technique. Other modelers use static waveshapers. The Axe-Fx triode models incorporate feedback so if there is a virtual cathode cap the stage is less linear in addition to having more gain."
Cliff:
"The key to a good Boogie sound, IMO, is the Fat Switch. This is the Treble Pull Shift on the IIC+ and the Pull Fat on the Mark IV. Mesa knew this and the Lead 2 modes on the Triaxis all had the treble shift engaged by default."
"The key to a good Boogie sound, IMO, is the Fat Switch. This is the Treble Pull Shift on the IIC+ and the Pull Fat on the Mark IV. Mesa knew this and the Lead 2 modes on the Triaxis all had the treble shift engaged by default."
"The IIC+ does not have a gain boost and doesn't need one. There is plenty of gain. The Pull Deep switch engages a large cathode cap on the final triode stage. With Pull Deep off there is actually a shelving response into the power amp (bass is reduced)."
"To emulate Pull Shift on the Bass control: "Put a Tilt EQ before the amp block with a frequency of 320 Hz and a gain of -3 dB. Set the Level to +3 dB".
Here’s the original “repair” manual.
The Rhythm (clean) channel hasn’t been modeled, so the models all refer to the Lead channel.
USA IIC+: Lead Master Pull Bright off, Pull Deep off
USA IIC+ Bright: Lead Master Pull Bright on, Pull Deep off
USA IIC+ Deep: Lead Master Pull Bright off, Pull Deep on
USA IIC+ BRT/DP: Lead Master Pull Bright on, Pull Deep on
The IIC+ doesn’t have features as the Mark IV or V. Still, it isn’t easy to dial in. Cliff’s guidelines to dial in the IIC+:
“The old version of the model incorrectly referenced the Mark IV tone stack. These tone stacks are identical except for the taper of the mid pot. The IIC+ has a linear pot and the Mark IV has a Log10 pot. I had it backwards in my earlier comments. My guess is that Mesa found that turning the midrange down sounds best (and it does) so they changed the pot taper to do this automatically since noon on a Log10 pot is equal to a 1.0 on a linear pot.
Commensurate with (1) I found myself turning the midrange down as well as the bass and turning the treble up.
I think the default Master Volume value is a bit high so you may want to turn that down. I've reduced the default for Quantum 2.03.
Turn the bright switch on. Every bit of information I've found says that people typically used the Pull Bright on the Volume knob. This is equivalent to the Bright switch under the Treble control on the model. I always turn it on and I've set it on by default for Q2.03.
USE THE EQ. The tone stack is pre-distortion which is atypical for a high-gain amp. Tone stacks are almost always post-distortion. Since the tone stack is pre-distortion you need to do your post distortion tone shaping using the EQ. The tone controls set the feel and the distortion texture, the EQ shapes the final tone. I like to do a gentle V-curve.
These were my settings for a killer high-gain tone: Model: USA IIC+ / Input Drive: 8.1 / Overdrive: 9-10 / Bass: 1.0 / Midrange: 1.8 / Treble: 8.9 / Presence: 4.5 / MV: 4.0 / Level: -20 dB / Bright Switch ON / 80 Hz: 4.8 / 240 Hz: 2.6 / 750 Hz: -4.5 / 2200: -0.2 / 6600: 0."
Commensurate with (1) I found myself turning the midrange down as well as the bass and turning the treble up.
I think the default Master Volume value is a bit high so you may want to turn that down. I've reduced the default for Quantum 2.03.
Turn the bright switch on. Every bit of information I've found says that people typically used the Pull Bright on the Volume knob. This is equivalent to the Bright switch under the Treble control on the model. I always turn it on and I've set it on by default for Q2.03.
USE THE EQ. The tone stack is pre-distortion which is atypical for a high-gain amp. Tone stacks are almost always post-distortion. Since the tone stack is pre-distortion you need to do your post distortion tone shaping using the EQ. The tone controls set the feel and the distortion texture, the EQ shapes the final tone. I like to do a gentle V-curve.
These were my settings for a killer high-gain tone: Model: USA IIC+ / Input Drive: 8.1 / Overdrive: 9-10 / Bass: 1.0 / Midrange: 1.8 / Treble: 8.9 / Presence: 4.5 / MV: 4.0 / Level: -20 dB / Bright Switch ON / 80 Hz: 4.8 / 240 Hz: 2.6 / 750 Hz: -4.5 / 2200: -0.2 / 6600: 0."
For another take on the IIC+ sound, try the USA PRE Yellow model. This is the IIC+ mode of MESA’s Triaxis preamp. It has Pull Shift and Pull Bright enabled by default. Some players find this model easier to dial in (and some actually prefer its sound to the IIC+).
Quantum firmware 3.03 brought us the "Metallica's IIC++" model. The details are sparse. It's the model used by Metallica for their live sound. Whether this model is based on one of the rare real IIC++ amps, has not been disclosed.
MESA equipped the IIC+ with EV-12L speakers. Try stock cab #105. Red Wire sells IRs of original IIC+ cabinets. Alt. try stocks cabs #19 and #150, Rectifier/V30 cabinets or cab #108 (Petrucci’s own cab with V30s).
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