Mesa Rosette 300 Two:Eight, Owner'S Manual

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impedance is approx. 1M ohms). It is always good practice to turn down the PICKUP GAIN control and mute the channel whenever
connecting or disconnecting your instrument to prevent pops from being sent to the internal speaker and also to the DI output.
MIC / PICKUP SWITCH
This switch selects between the MIC INPUT and the PICKUP INPUT on channel 1. If phantom power
is enabled on the MIC INPUT, the PHANTOM POWER LED will switch off when the PICKUP INPUT is selected.
MUTE SWITCHES
These switches mute the audio signal being sent to the respective channel’s DIRECT OUTPUT, HEAD-
PHONE OUTPUT and SPEAKER OUTPUT for silent tuning with a tuner connected to the instrument cable and then through to the
amp. When the switch is in the up position, there will be NO audio present at the DIRECT OUTPUT jack, HEADPHONE OUTPUT
jack, or the SPEAKER OUTPUT jack. This switch can also be used to place the channel into standby mode before and between sets
without adjusting any of the controls.
NOTE: The MUTE function can also be accessed remotely via a standard latching tip-to-ground on/off footswitch connected to the
MUTE FTSW jack located on the REAR PANEL. The Front Panel MUTE toggle switches must be in the down (PLAY) position for the
remote foot-switched functions to work properly. MESA sells Rosette specific Mute footswitches (one and two button) separately through
our Authorized Dealers and Distributors, our Parts & Accessories Online Store, or by contacting our Customer Service department.
PHASE SWITCHES
These switches set the PHASE (or polarity) of the channels to all outputs including the speaker output.
Depending on how your instrument’s pick-up or microphone is wired, it can be either in PHASE or out of PHASE - there is no way to
tell by looking at it. Under some conditions, if the signal from your instrument and the signal from the speaker are of the same polar-
ity, acoustic feedback issues can become an issue. Set this switch to the position that produces the minimum tendency for feedback
before attempting to use the equalization for feedback control.
HI-PASS FILTERS
These controls are an important feature in maintaining control over the extreme low frequency response,
especially under higher volume conditions. This precision 2-pole variable frequency filter has a turnover frequency that sweeps from
40Hz – 200Hz with a smooth, minimum-ripple response. While HPF’s have been standard fare within the pro audio industry for de-
cades, this feature has only recently begun to appear in acoustic instrument and bass amplifiers within the past few years (with a few
notable exceptions). This variable filter helps you coordinate and control the sub-sonic harmonics generated by the acoustic cavity of
larger instruments (like cello, mando-cello, upright bass, viola, Jumbo guitars and even some dreadnought guitars). Starting with the
control fully counter-clockwise, plug in your source and slowly increase the volume of the channel being tuned until you hear the very
beginning of low frequency feedback (don’t let it run away into feedback, of course). At this point, rotate the HI-PASS FILTER control
clockwise until this low frequency ring is no longer a problem. As a tone enhancement feature, if your instrument feels “boomy” or
“woofy” on the low end, try rotating this control clockwise until you hear adequate improvement before attempting to adjust the BASS
EQ. Experimentation and practice is key with this approach and it can be a musician’s best kept secret to getting great Tone in many
different musical applications – live performance, recording, and mixing especially.
GAIN CONTROLS & CLIP LEDS
The GAIN controls in both channels determine the input gain of the first gain stage in
their respective channel, and thus the level at which the following stages operate. The red CLIP LED provides a visual indication
of the status of the drive signal level and how much preamp clipping might be present. In general, it’s not desirable for this LED to
flash except maybe on the momentary peaks of the audio signal. Even then, it’s best to avoid it if possible. We have found, for most
modern pickups, settings in the range of 10:30 – 1:30 provide ample signal level to achieve great performance. Older Instruments/
Pickups and or microphones may have output signals that find you outside this median range, which is fine. Just be aware of the
INPUT signal level by using your ears and the CLIP LEDs for reference as to peak levels
FX SENDS
These controls adjust the level of the signal that is sent to the effects DSP engine or the EXTERNAL FX LOOP
SEND jack (post GAIN control to ensure the effects input levels are relevant to GAIN level). Generally, if the MASTER EFFECTS
(Return) control is set to the 1:00 position, this FX SEND control will fall within the 10:00 and 3:00 range. If you then need more Effect
than this, you would increase the FX MASTER control to achieve this while the FX SEND control remains within the 10:00 – 3:00
positions. This scenario will provide the cleanest input signal and avoid clip at the input of the on-board processor or any external
effects or processors interfaced to the FX LOOP. The reason for providing both the FX SEND and FX MASTER controls is to allow
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