SWR Sound Bass Combo Amplifier - Manual (Page 6)

BLACK BEAUTY – FRONT PANEL FEATURES
INPUT JACKS
Both input jacks 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 by using two instruments
simultaneously. However, the main applicational use for the two separate input jacks is their difference in
level, as the Passive/Active input has five times more gain than the Active input. In other words, it’s not
necessarily intended as a “submixer” for two instruments, but no harm will come from having two instruments
plugged in at once. Please read below for more details.
PASSIVE/ACTIVE INPUT JACK
This input jack is designed to accommodate both “passive” instruments and most “active” instruments. A
passive instrument has no built-in preamp and does not use a battery, while an active bass utilizes a battery-
operated preamp for gain, tone controls, or both. The Passive/Active Input will work with all instruments having
a maximum output of less than 1 volt RMS. Some active pickups such as EMG, Bartolini, etc., use batteries
for operation and will work perfectly using this input. Instruments made by MTD, Sadowsky, Modulus, etc.,
have active electronics that are suited for use in the Passive/Active input.
Generally speaking, try this 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/Active 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 JACK
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 greater than 1 volt RMS. The number of bass manufacturers has
increased significantly over the years, and it’s impossible to try and keep track of them all. Generally, if you
have very “hot” pickups and/or tone controls installed in your instrument, and you use them to boost the level
of your bass signal 10 dB or more, you may find the Active input more compatible. The best judge is your own
ears.
If you’re using a keyboard or bass pedal with the Black Beauty, 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, make sure the preamp clip
LED indicator is not lighting. If the preamp stage is not being driven into clipping, replace the battery in your
instrument.
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 (“MIN”) if the
Master Volume is 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 overall loudness.
PREAMP CLIP LED
The preamp clip LED will light whenever the preamp, tone section or output buffer reach clipping (run out of
4 • BLACK BEAUTY OWNER’S MANUAL