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As
well as the extruded aluminum heatsink, the power amp is cooled
by a thermostatically controlled fan. This fan turns on when
the heatsink reaches 50 degrees centigrade and turns itself
off when the heatsink reaches 40-45 degrees centigrade. This
allows for "silent running" when used at low volumes.
Be sure to leave at least a 1/2" clearance between the
vent on the left side of the Basic 350 and the side of any rack
case or enclosure you should happen to install your amp in.
This will allow for the hot air to escape.
Everybody
at SWR sincerely hopes that the purchase of our product adds
to the enjoyment of your playing and that it lives up to all
your expectations and more!
FRONT
PANEL FEATURES
PASSIVE/ACTIVE
INPUT JACK
A "passive" instrument has no
built in preamp and does not use a battery. On the other hand,
an "active" bass utilizes a battery operated preamp
for gain, tone controls, or both. Although labeled "Passive,"
the Passive Input will work with all instruments having a maximum
output of less than 1 volt RMS. Some pickups such as EMG, Bartolini,
etc., employ batteries for operation and will work perfectly
using the Passive input. Instruments made by Pedulla, Tobias,
Sadowsky, Modulus Graphite, etc., have active electronics and
should also be operated in the Passive input.
Generally
speaking, try the Passive input first. If you hear a small amount
of distortion and the preamp clip LED is not activated, try
using the Active input jack. If the Active input does not correct
any audible distortion, check the battery in your bass.
NOTE:
If you would like to overdrive the first TUBE stage, this can
be accomplished by using an external preamp between your instrument
and the Passive input. To obtain optimum sound when trying this,
make sure the preamp clip LED is not activated. If this occurs,
turn down your Gain control until the LED does not light. The
first preamp tube stage is NOT monitored by the preamp clip
circuit for this reason.
ACTIVE
INPUT
The Active input jack should be used with
instruments having a built-in (on board) preamp or other sound
sources that will produce output levels exceeding 1 volt RMS.
Known basses that should use the Active input are the Kubicki
X-Factor and some older Ovation electrics. Some really "hot"
pickups installed in your instrument may find the Active input
more compatible. The best judge is your own ears.
If
you are using a KEYBOARD or BASS PEDAL with the Bass 350, we
have found the best choice to be the Active input.
NOTE:
Using the Active input with passive basses (active instruments
will always employ a battery) may result in a loss of high end
transients. Players who roll off their high end starting at
about 2KHz, or prefer a "darker" sound, may find this
input more to their liking.
If
you hear some distortion with your active bass and are using
the Active input, CHECK YOUR BATTERY!! Also, make sure the preamp
clip LED indicator is not lighting. This will save you and a
service technician a lot of aggravation.
GAIN
CONTROL
The Gain control adjusts the volume of
the preamp section. Since the Gain control is similar to a "pad,"
a small amount of signal will be heard even with the Gain control
rotated fully counter-clockwise (with the Master Volume up).
After
all EQ settings and the Aural Enhancer are set, the Gain control
should be raised until the preamp clip LED barely flashes when
your loudest note is struck. This will insure maximum signal
to noise ratio and prevent unwanted clipping of the preamp section.
NOTE:
The Gain can serve as an EFFECTS SEND LEVEL ADJUSTMENT. If your
effect is being overdriven, turn down the Gain control and readjust
your Master volume for correct, overall loudness.
PREAMP
CLIP LED
The preamp clip LED will light whenever
the preamp, tone section or output buffer reach clipping (run
out of headroom). This function does NOT monitor the first tube
stage of the Passive input.
In
the event the clip indicator lights, turn down the Gain control.
Since this circuit monitors the tone controls, boosting any
one of them can cause the clip LED to activate. Once again,
you may leave the tone control at its desired level, but turn
the Gain control down further.
AURAL
ENHANCER
The Aural Enhancer was developed to bring
out the fundamental low notes of the bass guitar, reduce certain
frequencies that help "mask" the fundamentals and
enhance the high end transients. This effect becomes more pronounced
as the control is turned to maximum. The result is a more transparent
sound and is especially noticeable with a slap style of playing.
A
particularly favorite setting for live gigs is at about 2 o'clock.
This position of the Enhancer brings out both the low end fundamentals
and crisp highs and, at the same time, adds a little lower midrange
to help cut through the band.
ACTIVE
TONE CONTROL SECTION
BASS
CONTROL
The Bass Control cuts or boosts the lower
or bass frequencies. Starting at mid-center click-position,
turning the control counter clockwise cuts the bass response
and turning the control clockwise boosts the bass response.
The
Bass control employs a shelving type circuit and boosts or cuts
the bass response + or - 15dB from about 30 Hz to 100 Hz.
MID
RANGE SECTION
LEVEL
CONTROL
The Level control cuts or boosts the frequency
set by the Frequency control. Starting at mid-position, turning
the Level control counter clockwise cuts the desired tone. Turning
the Level control clockwise boosts the desired tone (set by
the Frequency control). WHEN THE LEVEL CONTROL IS SET AT MID
(CENTER CLICK) POSITION, TURNING THE FREQUENCY CONTROL WILL
HAVE NO AFFECT ON THE SOUND.
It
is suggested that to find the midrange area you are looking
for:
1.
Adjust the LEVEL control to the full boost or cut position.
2. Rotate the Frequency control until the desired area you wish
to cut or boost is found.
3. Adjust the Level control to the desired amount of cut or
boost
FREQUENCY
CONTROL
The Frequency control sets the area that
is to be cut or boosted by the Level function. If the Level
control is set at mid-position, turning the Frequency knob will
have NO affect.
Some
hints: If you need to "cut through" the band a little
more, try boosting 200 to 400 Hz. If you like a more transparent
sound, try cutting 800 cycles. The midrange area is especially
useful in controlling fretless basses and their inherent qualities.
TREBLE
CONTROL
The Treble control is a shelving type
tone control that cuts or boosts the high notes and their octaves.
Starting from mid position, turning the control counter clockwise
cuts the highs while turning the control clockwise boosts the
treble region.
Range
of the Treble control is from 2KHz to 14KHz.
EFFECTS
BLEND CONTROL
This function "blends" the signal
sent from your bass, etc., with that coming from your effects
unit. With the Effects Blend full counter clockwise, no signal
from your effects will be heard (dry). As you turn this control
clockwise, more of the effect can be heard in the overall sound.
When the Blend knob is full clockwise (wet), no true or unaffected
signal is heard other than what your effects unit provides.
If
your effects unit has a similar control, adjust it to the FULL
"WET" POSITION. This will avoid any possible phasing
problems.
The
Blend circuit is similar to that used on recording consoles
with the effects loop on a "side chain" to the normal
circuit.
Unless
the control is set to the full wet position, you will always
get the full sound of your instrument AND get the diversity
an effects unit offers. This circuit is also effective in reducing
noise generated by effects units because it is located after
the gain stages in the preamp.
The
Effects Blend functions only when the EFFECTS LOOP IS BEING
USED. It is activated when a 1/4" phone plug is inserted
into the Effects Receive jack. See the "Effects Loop"
section for more information.
NOTE:
PULLING THE EFFECTS BLEND CONTROL KNOB OUTWARD DEFEATS THE INTERNAL
LIMITER CIRCUIT. PUSHING THE CONTROL BACK IN, ACTIVATES THE
LIMITER.
MASTER
VOLUME CONTROL
The Master Volume adjusts the level being
sent to the power amplifier in your Bass 350. Hence, controlling
the overall volume of the product. It DOES NOT affect the level
of the record XLR output in the "line" position.
Losses
caused by effects units can be recovered by increasing the Master
Volume.
FAN
ON/OFF SWITCH
Switching the Fan On/Off switch to the
"On" position allows the Bass 350's internal cooling
fan to operate, keeping the amplifier's heat sink cool. Switching
the Fan On/Off switch to the "Off" position defeats
the Bass 350's internal cooling fan. This position is suggested
for situations such as recording where unwanted fan idle may
be audible.
POWER
ON/OFF SWITCH
Moving the On/Off switch to the "On"
position activates the electronics as indicated by the red LED
being lit.
LIMITER/COMPRESSOR
CIRCUIT
This circuit is located after (post) the
Master Volume and before (pre) the power amplifier. Therefore,
the limiter is driven by the Master Volume. Its threshold (starting
point) is preset by the factory so that the user can get maximum
overall apparent volume without unduly overdriving the power
amplifier or internal speakers. You may either activate or defeat
the limiter via the Effects Blend knob. The "in" position
activates the limiter. The "out" position defeats
this feature.
LIMITER
ACTIVE LED
When the threshold of the limiter circuit
is reached the green Limiter Active LED will light. This LED
will obviously be inactive when the Limiter is defeated or when
playing at lower levels.
REAR
PANEL FEATURES
BALANCED
XLR OUT
The Balanced XLR out is a true electronically
balanced record out. The signal appearing at the XLR out is
governed by the position of the Line/Direct switch. In the LINE
position, all front panel controls are functional except the
Master Volume, and the signal is essentially the same as that
heard through your speaker system. The output level in the Line
position is adjusted by the GAIN control on the front panel.
If you are using an effect, this will also appear mixed in the
signal when you are in the line mode.
In
the DIRECT position, the Balanced XLR out becomes an active
TUBE direct box. No front panel controls are functional and
the level is only adjustable via your instrument.
Wiring
for the XLR connector is as follows: Pin 1 = ground, Pin 2 =
+, Pin 3 = -(American Standard)
NO
PHANTOM POWER (48V SUPPLY) SHOULD BE APPLIED TO THIS OUTPUT.
DOING SO MAY DAMAGE THE INTERNAL CIRCUITRY.
LINE/DIRECT
SWITCH
The Line/Direct switch gives the user
the option of either a line signal (preamp out) or direct signal
from the instrument. The signal appearing at the XLR out is
slightly "hotter" than normal DI's. You may want to
inform the engineer of this condition.
To
use the Line/Direct function, position the knob in the desired
location. Make sure the switch is all the way to the left or
right to avoid intermittants.
NOTE:
Turn off transients appear at the record outs when the amplifier
is shut down. It is recommended that equipment being used in
conjunction with the record out be turned down, off, or disconnected
BEFORE the Bass 350 is turned off.
TO
TUNER INPUT
The To Tuner input allows the user to
plug their instrument tuner into this jack and "tune up"
without having to unplug and go back and forth from amp to tuner.
This feature is totally isolated from the rest of the preamp
and will function regardless of the settings on the front panel.
Being on a side chain (isolated) also avoids loading down of
the instrument causing a loss in dynamic range.
To
use this feature, plug in a shielded patch cord from the To
Tuner input to the input jack on your tuner. Turn the amplifier
on and you're ready to go. If you do not wish to monitor your
sound during the tuning process, you may turn down the Master
Volume.
EFFECTS
LOOP
THE EFFECTS LOOP MUST BE USED IN CONJUNCTION WITH THE BLEND
CONTROL ON THE FRONT PANEL. WHEN THE BLEND CONTROL IS IN THE
"DRY" POSITION, NO EFFECTS WILL BE HEARD.
The
Effects Loop should accept any effect such as a chorus, etc.
It is designed as a "side chain" function and works
exactly like that of studio consoles. Many effects on the market
have input level adjustments. For instance, some units have
a switch that you can set for either -20 dB or +4 dB. In all
cases, these should be set for 0 dB (if available) or +4 dB.
The level going to your effect is controlled by the Gain control
on the front panel.
Use
of the effects loop should greatly reduce the noise generated
by effects units (as compared to using the effect between your
instrument and the input jack). This is because the loop is
after the preamp gain stages.
SEND
Run a shielded patch cord from the SEND
jack to the INPUT of your effects unit. Output impedance of
the send jack is 100 ohms. This jack can be used as a line level
output to use in conjunction with a slave power amp such as
SWR's Stereo 800. It may also be used as an unbalanced record
out.
RECEIVE
Run a shielded patch cord from the RECEIVE
jack to the OUTPUT jack of your effects unit.
All
patch cords used with effects should be as short as possible
and should be routed as direct as possible. Running patch cables
over the top of the Basic 350 (as with any amplifier) could
induce hum in the cables.
One
unique feature of the receive jack is the ability to practice
a part along with pre-recorded music. To accomplish this, insert
a tape recorder or other sound source into the Receive jack
(make sure it is a MONO source). Using the Blend control, adjust
the level of recorded music from the Receive to the "live"
sound of your instrument. The mixed sound will be heard through
your speakers. Besides pre-recorded music, this is an excellent
way to practice along with drum machines.
Input
impedance of the Receive jack is 27K Ohms minimum.
NOTE:
Inserting a plug into the Receive jack activates the Effects
Blend control. The control receives this command through the
ground created by the phone plug making contact with the jack.
The plug must be a mono plug (tip and ground). If you have a
stereo plug only, tie the ring and the ground together.
SPEAKER
JACKS
Two 1/4" phone jacks wired in parallel
are provided for hooking up your speaker system(s). Minimum
load or impedance that can be used with the Basic 350 is 2 OHMS.
For instance, you could use two 4 ohm, four 8 ohm or eight 16
ohm enclosures.
It
should be noted that the Bass 350's preamp section can be used
for recording purposes only using the XLR out. Therefore, it
can be run with no speakers attached to the speaker jacks. This
is unlike most amps on the market.
ALWAYS
USE SPEAKER CABLE MADE OF 18 GAUGE WIRE OR HEAVIER (THE HEAVIER
THE WIRE, THE LOWER THE GAUGE). NEVER USE SHIELDED CABLE OR
CABLE INTENDED FOR USE WITH YOUR INSTRUMENT TO HOOK UP YOUR
CABINETS.
SPEAKER
FUSE
The speaker fuse is provided to protect
your speakers in the unlikely event of a power amp failure or
to protect your power amplifier from incorrect speaker impedances
or hookups. Size and rating of the fuse is 10 amp, fast blow.
Do not defeat the purpose of this feature by using a higher
rated fuse as it could void your warranty and further damage
your amp.
The
fuse can open as a result of a fault in the speaker cable, the
speakers themselves, or the power amp being sent well into clipping.
With this in mind, it is wise to carry extra fuses at all times.
A/C
OR MAINS FUSE
This fuse is provided to protect the internal
electronics against power surges, etc. It also protects the
unit against itself should one of the internal components fail.
If this fuse should open, replace it with the same type of fuse
and rating. DO NOT DEFEAT THE PURPOSE OF THIS FEATURE
BY USING A FUSE OF A HIGHER VALUE. IT WILL ONLY VOID YOUR WARRANTY!
Proper
size of the AC fuse for all countries is 3AG. Proper rating
of the fuse is as follows:
Japan:
8 amp slo-blo
United States: 7 amp slo-blo
Europe (240V): 4 amp slo-blo
AC
CORD RECEPTACLE
Accepts a standard A/C power cable (supplied
with the Basic 350 in the United States) used with almost all
current musical, professional and household electronic devices.
We recommend great care when packing up. If your unit is not
in a rack case, put the cable in your instrument or accessory
case or leave it attached and looped around one of the rack
handles. If it does become misplaced, replacement will be easy
at almost any appliance store, super market or the like.
PLEASE
NOTE: the rating for this cable is 3 conductor, 10 amperes minimum.
Look for this rating on the cable. Make sure the cable is plugged
in all the way in both the amp and the wall socket.
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