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Standard
features include two input jacks, gain and master volume controls,
integral limiter, bass and treble controls, 4 band/3 octave
variable graphic equalizer, two effects loops, balanced direct
or-line out and adjustable electronic crossover for bi-amping.
Tlxe
PB--200 is rack mountable taking up two rack spaces X3 1/2 inches)
by 8 3/4 inches deep (measured from the front panel back). The
PB-200 weighs only 13 pounds with a 16 pound shipping weight.
It is easily carried by one of two handles secured to the front
panel.
The
tube employed in the preamplifier is a specially selected 7025
(or 12AX7) and should not need replacing for one to three years
depending on usage and care of your unit.
We
truly hope you enjoy your amplifier and find it all you have
ever wanted in a bass amplifier and more. If you ever have any
questions or suggestions, please don't hesitate to call or write
us at the factory.
FRONT
PANEL FEATURES
HIGH
AND LOW GAIN INPUT JACKS
Both inputs accept a standard 1/4"
phone plug and both inputs can be used at the same time. Since
the two inputs are totally independent, no loss in volume or
tone will occur if two instruments are used simultaneously.
Keep in mind, however, that the Hi Gain input has five times
more gain than the Low Gain input.
GAIN
CONTROL AND PRE-AMP CLIP LED
The Gain Control adjusts the volume of
the preamp section. After the tone controls, Variable Graphic
Equalizer and Limiter is set to your liking, the Gain Control
should be adjusted to where the Preamp Clip LED barely flashes
upon striking your loudest note. Now adjust the Master Volume
to the desired volume level. Utilizing these controls in this
manner assures the user of maximum signal to noise ratio with
no distortion caused by the preamp circuits "clipping."
The
Pre-Amp Clip LED will light if any portion of the preamplifier
reaches clipping or runs out of headroom. This can be caused-by
the Gain Control being set to high or any tone or equalizer
control set in'a high boost position. To correct this condition,
turn down one of the previously mentioned controls.
NOTE:
The Pre-Amp Clip LED indicates that at some point the preamplifier
is clipping. No harm is being done to your amplifier and if
desirable,, can be played under these conditions.
LIMITER
The Threshold Control sets the level at
which limiting begins to take effect. At that point the LED
will light. Maximum'limiting will occur with the Threshold Control
set in the Maximum position. The Limiter is completely out of
the circuit with the Threshold Control set in the Minumum position.
Loss in volume caused by extreme limiting can be overcome by
increasing the Master Volume control.
NOTE:
If the Threshold is set at maximum and still no limiting effect
occurs, the Gain Control is set to low and should be increased
to a desired level.
AURAL
ENHANCER
The Aural Enhancer was developed to help
bring out the fundamental notes of the bass guitar and give
a resulting frequency response similar to that used for recording
the bass in the studio. This effect becomes more radical as
the control is turned to maximum. The result is a more "transparent"
sound and is especially noticeable with a slap style technique
of playing.
BASS
CONTROL
The Bass Control is a shelving type tone
control that cuts or boosts the lower of bass frequencies from
mid-position. Starting at mid-position, turning the control
counter clockwise cuts the bass response and turning the control
clockwise boosts the bass response.
VARIABLE
GRAPHIC EQUALIZER
Level
Control
The Level Control cuts or boosts the frequency
set by the Frequency Control directly beneath it. It is used
in the same manner as you would a graphic equalizer. Starting
at mid-position, moving the slider towards +15 boosts and moving
the slider towards -15 cuts that particular frequency.
Frequency
Control
The Frequency Control selects the center
frequency that will be cut or boosted by the Level Control directly
above it. If the-Level Control is at 'O' or mid-position, moving
the Frequency Control will have no effect on the sound. The
Frequency Control covers a three octave range.
To
better understand how the Level and Frequency Controls work
with each other, try the following example:
1.
Set the Gain and Master Volume Controls for listening levels.
2. Set all tone and level controls at mid-position and turn
all frequency controls full counter-clockwise.
3. Strike the open E string on the bass and move the Level Control
on the first band of your equalizer to +15 (the Frequency Control
should be set at 40 Hz which is the fundamental that the open
E string produces). The change in sound and pressure levels
is a result of the fundamental E note being increased by'approximately
15dB.
4. Keeping all controls in their present positions (Level Control
at +15 and Frequency Control at 4OHz) strike your open E string
again and move the Frequency Control from 4OHz to 16OHz.
As
the Frequency Control is moved from 4OHz to 16OHz you should
hear two increases in volume. The first will be at 8OHz or your
first overtone (harmonic) and the second will be at 16OHz or
the second harmonic of your open E string.
From
the above example, a few things come to mind! One, there's a
lot of information contained, in one note on your instrument,
two, if one position of the Frequency Control gives a much louder
sound or volume, you may have found the area of greatest efficiency
of your speaker cabinet and three, the tonal-variations you
can achieve with the Variable Graphic are.just about-infinite!
The
advantages of the Variable Graphic Equalizer in tone shaping,
correcting for 'dead spots' on the neck of your guitar and correcting
for speaker deficiencies should be obvious and with a little
bit of practice will become quite easy. An illustration showing
the relationship between the notes on the bass guitar and their
assigned -frequencies follows.
TREBLE
CONTROL
The Treble Control is a shelving type
tone control that cuts or boosts the high frequencies. Starting
from mid-position, turning the Treble Control counter-clockwise
cuts the highs and turning the control clockwise boosts the
high frequencies.
FREQUENCY
SHIFT
Starting from mid-position, and turned
counter-clockwise, the Frequency Shift boosts the low frequency
response while cutting the high frequency response. Turning
the control clockwise boosts the highs while cutting the lows.
This control is especially useful in making quick tonal variations
and helps compensate for room acoustics without having to change
your EQ or tone settings.
MASTER
VOLUME AND POWER AMP CLIP LED
The Master Volume controls the volume
of the internal power amplifier and the Balanced XLR jack when
switched in the Line position. The Master Volume does not affect
the levels at the Pre-amp out jack or the Crossover High and
Low Output jacks located on the back panel. Those are controlled
by the Gain Control only.
The
Power Amp Clip LED will light when the power amplifier reaches
maximum undistorted output. As with the Pre-Amp Clip LED, the
power amplifier can be run beyond this point and will cause
no adverse conditions.
POWER
SWITCH
Moving the Power Switch to the On position
will turn on your amplifier as indicated by the LED lighting.
REAR
PANEL FEATURES
EFFECTS
LOOP
The Effects Loop is provided for use with
an external effect such as a Chorus. Using the Effects Loop
lowers the noise heard at the speakers generated by the effects
unit. The output and input impedances seen at the To and From
Jacks were designed to give optimum performance from effects
units both new and old.
To
hook up your effect, run a shielded cable from the "To"
jack to the input of the effect and another from the output
of the effect to the "From" jack on the back panel.
When this is accomplished, your effect is now ready for use.
BALANCED
OUT
The Balanced Out is a true balanced.output
and serves two functions. In the "Direct" position,
the Balanced Out serves as a direct box and can be used for
recording or patching into a house P.A. System. No controls
on the front or back panel affect the signal appearing at the
XLR connector. In the "Line" position, all controls
on the front and back panels control the signal appearing at
the XLR,connector and the level is set by the Master Volume.
The
Line position can be used for recording directly into a tape
machine as well as going directly to the studio board. An external
power amplifier with a balanced input can be driven in the Line
mode.
Pin
out for the XLR connector are as follows: Pin 1= ground, Pin
2= Pin 3=
ACTIVE
ELECTRONIC CROSSOVER
HIGH
AND LOW OUT JACKS
The Crossover High and Low out jacks have
been provided for bi-amping capabilities. Present at the Low
jack are all frequencies below the point set by the Frequency
Control. Present at the High jack are all frequencies above
the point set by the crossover or Frequency Control. All patching
from these jacks should be done with shielded cable.
FREQUENCY
CONTROL
The Frequency Control sets the crossover
point or dividing point of the High and Low jacks. For example,
if the Frequency Control is set at about mid-position or 50OHz,
all frequencies below 50OHz will appear at the L<)w output
jack and all frequencies above 50OHz will appear at the High
output jack. Crossover slope is 12dB per octave.
USING
THE INTERNAL POWER AMP FOR BI-AMPING
The internal power amp in the PB-200 may
be used for amplifying either the low or high frequencies in
a bi-amp system. As a general rule., the bottom end or low frequencies
should have at least twice the power that the high frequencies
have. So.,if your slave power amp has a rating of 100 watts,
use it for the highs and the PB-200 for the lows. Once you have
selected the use for the PB-200,-run a patch cord from either
the high or low out jack to the Power Amp In jack. This automatically
stops any other signals from going to the internal power amplifier.
The level or volume of,the internal power amp is still controlled
by the Master Volume on the front panel. This allows the user
to compensate for sensitivity differences in the two power amps
being used.
EQ
FOOTSWITCH
Insertion of a footswitch into this jack
allows the user to turn on or off the Variable Graphic Equalizer.
With no,footswitch plugged in, the Variable Graphic Equalizer
is always on.
PRE
AMP OUT/POIVER AMP IN JACKS
The Pre Amp Out jack is an unbalanced
line out and can drive a slave power amplifier or-can be used
for a patch to a mixer, etc. The Pre Amp Out jack is before
the Master Volume and its level is controlled by the Gain Control
on the front panel. The Power Amp In jack is provided for bi-amping
capabilities (see Active Electronic Crossover section) and for
using the internal power amplifier by itself. Insertion of a
plug into this jack automatically disconnects the preamp signal
that normally is present. The volume of the power amp is still
controlled by the Master Volume control on the front panel.
USING
THE PRE AMP OUT/POWER AMP IN JACKS AS AN EFFECTS LOOP
These jacks can be used as a line level
effects loop. When used in this manner, the pre amp out jack
becomes the "To" and the power amp in jack becomes
the "From" effects jack. Refer to "Effects Loop"
for further information.
SPEAKER
JACKS
Two speaker jacks are provided for hooking
up your speakers. Always use good quality cable for your speakers
as it is the final link between the electronics and your speakers.
It should be at least made of 18 gauge wire or heavier (the
lower the gauge, the heavier the wire) and DO NOT use shielded
cable such as that used for your instrument. Minimum load for
the power amp is 4 ohms. This means that you can use one 4 ohm
cabinet, two 8 ohm cabinets, or four 16 ohm enclosures.
SPEAKER
FUSE
The Speaker Fuse is provided to protect
your speakers in- the unlikely event of a power amp failure.
Size and rating of the fuse is 3AG, 6AMP, FAST-BLOW. Do not
defeat the purpose of this feature by using a higher rated fuse.
The
speaker fuse can also open if there is a fault in the speaker
cable or the-speakers themselves. Therefore, it is always wise
to carry extra fuses at all times.
LINE
OR MAINS FUSE
The size and rating of the Line fuse is
3AG, 4Amp, SLO-BLO. NEVER replace this fuse with one of a higher
rating as it can only cause more damage to your unit and can
void your warranty.
A/C
CONVENIENCE OUTLET
The A/C Convenience Outlet is provided
to provide AC power to another piece of equipment. Check the
power rating to make sure that it is less than the rating written
on the back panel of the PB-200.
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