There's been a lot of complaining about the Mark IIC+ models. So I begrudgingly dragged the amp out of storage today (as it weighs a metric ton) and repeated the measurements and did some A/B tests. As expected the models are extremely accurate.



That being said it is a bear to dial in. Here are some tips:



1. 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.



2. Commensurate with (1) I found myself turning the midrange down as well as the bass and turning the treble up.



3. 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.



4. 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.



5. 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