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P
REFIX
™ P
RO
B
LEND
3
QUICK START
To combine microphone and pickup signals, first preset the microphone EQ to control
feedback, then mix in the pickup. The Prefix™ProBlend has three ways to control feedback;
a Notch Filter, a Phase Switch, and a Semi-parametric Contour Control.
Follow these steps to achieve a strong, feedback-free sound.
1. Before you plug in, set all controls as follows:
• NOTCH and VOLUME fully counter-clockwise
• All sliders at their center positions
• BLEND slider at MIC position
2. Plug in the instrument first (with 9V alkaline battery installed), then plug in to your
amplifier, with the tone controls on the amp set as flat as possible.
3. Slowly increase the VOLUME until the guitar and speaker are approximately the same
level. Play the open E string and flip the PHASE switch. Leave the switch in the position
that sounds the deepest and clearest.
(for more on phase, see page 8)
4. Slowly increase the volume until the instrument starts to rumble with low frequency
feedback
5. Use the NOTCH FILTER to scoop out the lowest range of feedback, which usually starts
at the open low E string and continues up to about the forth fret G# on the same string
(often near two 'o clock).
6. Use the PHASE SWITCH to control the upper range of low frequency feedback, which
usually starts at the fifth fret A on the low E string and continues up to about the twelfth
fret E on the same string. Flip the PHASE SWITCH back and forth until you find the
position that subdues this range of feedback.
7. Slowly increase the VOLUME again, until the microphone just starts to squeal.
8. Lower the CONTOUR Level all the way down. Slowly adjust the Contour FREQUENCY
rotary control until the squealing feedback is eliminated. Raise the CONTOUR Level
slider (if possible) to just below the threshold of feedback.
9. Gradually mix in the pickup signal by adjusting the BLEND slider. The pickup signal will
add significant attack and definition to your sound.
10. Adjust the BASS and TREBLE controls as desired. Please note that these controls will
affect pickup signal only.
11. Double check the PHASE switch position until you find the clearest, feedback free
response.
12. Play your guitar as loud as you want..
F
ISHMAN
P
REFIX
™ S
ERIES
4
FUNCTIONS
Battery Compartment
Pull the small tab at the top of the Problend™
toward you. The body of the preamp will swing
out, revealing the BATTERY COMPARTMENT.
Install a fresh 9V alkaline battery.
Microphone Trim Control
A small circular potentiometer is located on the side of the preamp that faces the back of the guitar.
This control can be accessed by opening the battery compartment. Use this control to fine tune the
microphone volume, in relation to the pickup volume.To adjust the microphone trim control, set the
BLEND slider to the center position and, with a slotted jewelers screwdriver, turn the potentiometer
until both the microphone and pickup levels are balanced to your taste.
POWER
The Prefix™ProBlend has no ON/OFF switch. To turn on the power, plug an instrument cable into
the endpin jack. To conserve the battery, remove the instrument cable from the endpin jack when
the unit is not being used. It is a good idea turn down your amp or mixer's input before you plug into
this input. Doing so will protect your speakers (and your ears) from loud pops and thumps.
Clip / Battery Low LED
This light has three distinct functions:
1. Power Up Indicator
The Clip/Batt Low LED will flash momentarily when you first turn on the preamp. Some people
ask us why this light doesn't stay on, like a conventional pilot light. We feel a steadily lit LED
devours too many precious hours of battery life. We prefer instead to conserve the battery with
a quick flash of the LED to indicate that the preamp is powered up.
2. Clip Indicator
If the LED flashes while you are playing, you are driving the preamp into distortion. Lower the
Treble and/or Bass slider until the flashing stops. This indicator may also flash as you approach
the end of the battery's useful life.
3. Low Battery Warning
When the Clip/Low Batt LED lights steadily, it is time to change the battery.
Volume
Affects both microphone and pickup levels. Set this as high as possible (without distorting
your amp or mixer) for the cleanest signal.