Mesa/Boogie JP-2C Owner'S Manual Download Page 19

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The highest region of the GAIN (2:30 – 5:30) is all about saturation. Up here the signal gets much fatter in the low end and the top
end begins to recede to create a round, compressed sound. Dynamics become slower with lower peaks and a more legato, creamier
feel is produced. Channel 3 is absolutely over the top when the GAIN is run this high. Up here you will notice the Tone controls have
a diminished effect on the sound as the notes are so saturated and their character has been pre-determined by the way each Mode
is voiced and how it reacts to this level of gain.

NOTE: Using the upper range of the GAIN control invites possible microphonic or other gain related issues to become more of a
possibility. Avoid setting all the Controls–GAIN and TONE–in their highest regions as the combination of all of them pushes both
circuit and tubes to the edge of their stable region. Applying the SHRED Mode can exacerbate these tendencies further and it is near
impossible to use all the Controls in their highest ranges with SHRED activated. Doing so will likely cause a high pitched squealing
or feedback that is easily remedied by reducing one or more controls, especially the GAIN and TREBLE.

MASTER

This control determines the overall output level of each Channel and it is located at the very end of the preamp. By

using it in combination with the GAIN control, any amount of preamp signal strength, gain, (within a Modes’ parameters) can be

achieved at any playing volume. Once you have dedicated the Channels to their respective sounds with
the Controls, you can then balance the volume levels (output) of the Channels using the MASTER controls.

For general applications and to get the best performance out of all the Modes we recommend MASTER
settings in the 9:00 – 12:00 range with most people settling in around 10:30 for average playing volumes.

Some purists like to run a MASTER all the way up and raise the GAIN until they reach their desired sound – thinking that this achieves
the purest sound. In theory, they believe this resembles removing the control altogether from the signal path, and in a way it does.
However most all the “vintage non-master” amplifiers they are seeking to emulate have discrete resistors at that place in the circuit
anyway to adjust or “tune” the output of the preamp to the power section’s individual sensitivity.

The MASTER is nothing more than a variable resistor that offers an infinite range of settings possibilities and makes the amplifier
many times more versatile with no sonic penalty. If you prescribe to this old school approach, then by all means, use the JP-2C this
way... it won’t hurt the amplifier. However you will be severely limiting the potential sounds you can achieve by removing the limitless
great sounding combinations of GAIN and MASTER settings.

Unlike many other MESA amplifiers where the Channel MASTER also acts as an EFFECTS SEND control, the JP-2C required a
different layout to ensure the authenticity of the MARK II-C+ circuit. Here Channel 1 uses that scheme (Channel MASTER doubling
as a SEND Level control), but the two high gain Channels (2 and 3) see the GAIN control doubling as the EFFECTS SEND control.
The reason for this has to do with the fact that it is really the LEAD DRIVE control on a MARK II-C+, which WAS responsible for the
SEND strength in a II-C+. Regardless, despite this difference in both origination of the signal and control placement, the Channels
balance out quite nicely and you should have no problem with signal levels at your processor(s).

PRESENCE

This control adjusts high frequencies above those of the TREBLE and is located in the power section, farther down-

stream in the signal path, and not in the preamp. The PRESENCE adjusts a specific zone of frequencies in the negative feedback
circuit of the power section that best suit the needs of each individual Channel.

You can think of the PRESENCE as a control that allows you to either clamp the power amp down,
compressing it and darkening the sound, or open it up and let the full spectrum of upper harmonics come
blazing through. It also has a great deal to do with how dynamic the signal is and how a sound will cut
through the mix in an ensemble environment.

At low settings (7:30 – 10:30) the sound will be warm and round with a more compressed feel and dynamic fluctuation will be limited.
As the PRESENCE is increased (11:00 – 2:30), the top end starts to become more dominant and that compression gives way to “cut”
and dynamic peaks jump out with startling speed and accuracy. At the top end of the control (2:30 – 5:30), a super aggressive blend
of upper harmonics dominate the sound and this region can be somewhat dangerous if it’s not applied in the right musical environ-

80Hz

240

750

2200 6600

80Hz

240

750

2200 6600

GAIN

TREBLE

MASTER

PRESENCE