SWR Sound Bass Combo Amplifier - Manual (Page 13)

TWEETER MODE SWITCH
This three-position switch gives you the choice of three different options for operation of the horn tweeter. In
the Full Range (top) position, the tweeter will reproduce an unattenuated signal of every frequency it sees
(roughly 2 kHz up to 15 kHz, within certain tolerances). The –6db (bottom) position reduces the level of the
tweeter’s outputs by 6 decibels, which to the ear sounds roughly as if cut in half compared to the Full Range
position. The Off (middle) position will defeat the tweeter’s output entirely.
Try starting with the switch in the Full Range position. If this sounds too “treble-y” to your ear and you still
want the touch of crispness that a tweeter provides, you can: a) Set the Tweeter Mode Switch to –6db; b)
Adjust the Treble tone control on the front panel; c) Try a combination of both. Those users with a
predisposition against a tweeter in general have the option to turn it off and leave it off, but we recommend
trying it out first.
SPEAKER MODE SWITCH
This two-position switch controls the signal sent from the power amplifier to your speaker cabinet (and
extension speaker if connected). When set to the On (top) position (default setting from the factory), the
Black Beauty will operate normally and the sound of your amplified bass will be heard from the speaker
cabinet. When set to the Off (bottom) position, that signal will be defeated regardless of the settings on the
front panel. This can be useful for silent practicing (in conjunction with the Headphones Jack, listed below), or
for defeating the audio while you re-patch cables or plug and unplug your instrument. This switch will not
affect the signal present at the various audio outputs (XLR, Effects Send, Tuner Out) or the Headphones Jack.
NOTE: If the volume on your instrument is up, and your Gain and Master Volume controls are up, and
especially if you’re seeing the Preamp Clip and Limiter Active LED’s illuminate while you’re playing…and
you can’t understand why you’re not getting any audible output from the Black Beauty, check the position
of this switch!
HEADPHONES JACK (STEREO ONLY)
By inserting a set of stereo headphones into this jack you can monitor your sound more closely in a studio
situation, or practice silently (when the Speaker On/Off Switch is set to “Off”) so as not to completely annoy
your neighbors. The headphone volume level is adjusted by the Master Volume. We suggest you begin with
the Master Volume full off (counter-clockwise), then slowly bring up the volume to the desired level. If you
hear some distortion in your headphones that isn’t present through your speaker system, turn down the
Master Volume. You are probably overdriving your headphones and could ruin them, to say nothing of what
you may be doing to your ears.
Any impedance headphones will work. However, optimum impedance is 75 ohms.
COMBO CABINET JACK/PLUG ASSEMBLY
The black cable/plug assembly that comes out of the cabinet and is connected to the rear panel (near the
text marked “Combo Cabinet”) is the means by which the power amp in your Black Beauty sends its signal to
the speaker complement. Both the plug and the jack it connects to are a special size, slightly less than the
typical 1/4" found on instrument and speaker cables alike. SWR strongly recommends that you not
disconnect this cable, as it is not meant to be (nor can it be) used as an extension speaker output. For
proper connection of extension speakers to your Black Beauty, please read below.
EXTENSION SPEAKER OUTPUT SECTION
This section of the manual will deal with the proper connection of extension speaker cabinets to the power
amplifier in the Black Beauty. We recommend that you read this section carefully, as power amplifiers,
mpedance and speaker cabinets are all crucial in determining how best to operate your new Black Beauty
with an extension speaker cabinet.
HOW IMPEDANCE AFFECTS POWER RATINGS
People often have questions about impedance. What is it? The root of the word “impedance” is the verb
“impede,” which means to block or resist. That’s what impedance is—resistance to power.
Power amps do not have a pre-determined impedance. They deliver power at whatever impedance the
speaker cabinet tells it to. That’s why you hear the term “slave amp”—amplifiers only do what they’re told. So
BLACK BEAUTY OWNER’S MANUAL • 11