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GENERAL
INFORMATION AND DESCRIPTION
The
Studio 220 Bass Amplifier was designed from the ground up for
specifically amplifying all bass instruments, Its features,
sound, packaging and performance specifications are the result
of numerous years of input from musicians, sound engineers and
studio engineers. It is the upgraded version of out first product,
the PB-200. A great deal of time was spent to insure that the
needs of the professional musician both on the stage and in
the studio were met and that all elements of their music will
be accurately amplified.
Housed
in an all aluminum chassis for lightweight and lasting beauty
is an extremely low noise tube preamp section and a solid state
power amp utilizing all discreet components, The power amp delivers
a minimum of 220 Watts RMS into 4 ohms and 140 Watts into 8
ohms.
Standard
features include Hi and Low Gain input jacks, Gain and Master
Volume controls, 4 band/3 octave Variable Graphic Equalizer,
two Effects Loops, Balanced Out with pad and ground lift, and
an adjustable electronic Crossover for Bi-Amp capabilities.
The
Studio 220 is rack mountable taking up two rack spaces (3 1/2")
by 8 3/4 " deep (measured from the front panel back). The
Studio 220 weighs 13.5 pounds with a 17 pound shipping weight.
It is easily carried and the front panel is protected by the
two handles secured to the front panel.
All
of us at SWR hope you enjoy your amplifier and find it all you
have ever wanted in an amplifier of this type.
RACK
MOUNTING INSTRUCTIONS
To
preserve the beauty and reliability of your Studio 220 Bass
Amplifier, we recommend that you install your amp in a rack
case. The Studio 220 is completely ready to be rack mounted
and needs no additional parts or accessories other than the
case itself.
Although
it takes up only two rack spaces, we recommend you use a three
rack space case. This will prevent the vents on the top and
bottom of your amplifier from being covered and allow for natural
cooling of the power section. No fan is needed in this condition
and you will not have to remove the rubber feet. If you still
would like to remove the feet, replace the screws as they help
to hold on the bottom of the amplifier
-- THIS IS VERY IMPORTANT!!!
FRONT
PANEL FEATURES
HI
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 PREAMP CLIP LED
The Gain Control adjusts the volume of
the preamp section. After the tone controls, Variable Graphic
Equalizer and Limiter are 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
Preamp 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 too 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 Preamp Clip LED indicates that at some point the preamplifier
is clipping. No harm is being done to your amplifier, however,
CONTINUAL CLIPPING CAN CAUSE DAMAGE TO YOUR SPEAKERS AND IS
NOT RECOMMENDED!
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 Minimum 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 too 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 or 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 toward +15 boosts and moving
the slider toward -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 "0" or mid-position,
moving the Frequency Control will have no affect 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 40 Hz which
is the fundamental 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 40 Hz) strike your open "E"
string again and move the Frequency Control from 40 Hz to 160
Hz. As the Frequency Control is moved from 40 Hz to 160 Hz you
should hear two increases in volume. The first will be at 80-
Hz or your first overtone (harmonic) and the second will be
at 160 Hz 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!
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 high and turning the control clockwise boosts the high
frequencies.
PULL
TRANSPARENCY FUNCTION
Moving the Treble control to the pull
"out" position activates the Transparency function.
This gives a boost of up to 12dB at frequencies above 5KHz enhancing
the sibilance of each note. For an extra "sweet" tone,
set the Treble Control to between 9 and 10 o'clock and activate
the Transparency function.
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 500 Hz, all frequencies below 500 Hz will appear
at the "low" output jack and all frequencies above
500 Hz will appear at the "high" output jack. Crossover
slope is 12 db per octave.
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 Preamp 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.
CONTINUAL CLIPPING OF THE POWER AMPLIFIER CAN RESULT IN SPEAKER
DAMAGE AND IS NOT RECOMMENDED!
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 or delay unit. Using this
feature 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. The
Effects Loop is
pre-EQ.
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. When this is accomplished,
your effect is now ready for use.
If
there is an "Input Level" adjustment on your effect,
it should be set at "0db" or the nearest setting.
BALANCED
OUT
The Balanced Out is a true balanced output
and serves two functions. In the "Direct" position,
it serves as an active 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
except the XLR Pad. In the "Line" position, all controls
on the front and back panels affect the signal appearing at
the XLR connector except the Master Volume. The level is set
by the Gain Control and the XLR Pad.
The
"Line" mode 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" position.
Pin
out for the XLR connector are as follows:
Pin 1 = Ground Pin 2 = + Pin 3 = -
XLR
PAD/GROUND LIFT
The XLR Pad is a continuous pad that adjusts
the output of the signal appearing at the balanced output. Since
it is a true pad, the signal (or volume) will not go completely
off when turned fully counter-clockwise.
When
used in the line mode, this feature allows the user to adjust
the level of the signal going to the "house system"
or tape deck etc. with the pad. You may now set your speaker
volume with the Master Volume and not affect the level at the
XLR. All of these levels should be set AFTER the Gain Control
is in the desired position.
The
ground connection of the XLR can be lifted (or disconnected)
by pulling the pad outward. In most applications, this will
not be necessary. If, however, you are experiencing a hum or
grounding problem with the balanced output, try lifting the
ground. Always be conscious as to which position this switch
is in.
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 crossover
or Frequency Control on the front panel. Present at the High
Jack are all frequencies above the point set by the Frequency
Control. The signals at these outputs are line level. You cannot
drive speakers from these outputs. All patching from these jacks
should be done using shielded cable.
Using
the Internal Power Amp for Bi-Amping The internal power amp
in the Studio 220 may be used for amplifying either the low
or high frequencies in a bi-amp system. As a general rule, the
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 Studio 220 for the
lows. Once you have selected the use for the Studio 220, run
a patch cord from either high or low out jack to the Power Amp
"in" jack on the back panel. This automatically stops
any other signals from going to the internal power amplifier.
NOTE:
An external or additional "slave" power amp is needed
for full bi-amp capabilities and should be used as noted above.
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 EQ is always on. This feature
will allow for one preset "sound".
PREAMP
OUT/POWER AMP IN JACKS
The Preamp 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 Preamp Out is located before the
Master Volume in the signal chain and its level is adjusted
by the Gain Control.
The
Power Amp In jack is provided for bi-amping (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
on the front panel.
Using
the Preamp Out/Power Amp in Jacks as an Effect Loop These jacks
can be used as a line level effects loop. When used in this
manner, the Preamp Out becomes the "To" and the Power
Amp In jack becomes the "From" effects. Refer to Effects
Loop section for further information.
SPEAKER
JACKS
Two speaker jacks are provided for hooking
up your speakers. Use good quality cable for your speakers as
it is the final link between the electronics and your speakers.
It should be made of at least 18 gauge wire or heavier (the
heavier the wire, the LOWER the wire gauge) and DO NOT use shielded
cable such as that used for your instrument.
The
power amp in the Studio 220 will deliver a minimum of 220 Watts
RMS under clipping at 4 ohms and 140 Watts at 8 ohms. It also
has a frequency response from 10Hz to 15KHz. Please make sure
that your speakers are compatible with these parameters as we
have found that some "bass" speakers cannot handle
frequencies under 40 cycles (a five string bass will put out
frequencies down to 30 Hz). Minimum load is 2 ohms.
SPEAKER
FUSE
The speaker fuse is provided to protect
your speakers in the unlikely event of a power amp failure.
The fuse can also open if there is a fault in the speaker cable
or the speakers themselves. Size and rating of the fuse is 3AG,
8 AMP, FAST BLO. Do not defeat the purpose of this feature by
using a higher rated fuse.
LINE
OR MAINS FUSE
The rating is 3AG, 4 AMP, SLO BLO. NEVER
replace this fuse with one of a higher rating as it could cause
damage and void your warranty.
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