SWR Sound PB-200 - Manual (Page 2)

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.