SWR LA 12 User Manual page 9

Tone Controls
The preamp and tone control circuit in all SWR L.A. Series amps is the same basic circuit featured
in our acclaimed Professional and Workingman's lines. We've condensed many of our "Pro" features
into the circuit... so now the SWR sound is "automatic."
For each tone control, rotating the knob counter-clockwise from the center "click" position will
reduce (or cut) the level of bass, mid or treble. Rotating the knob clockwise will boost these
levels. (See the L.A. Series Specifications for the center frequencies of these controls.)
The BASS control works in a range that will be useful under most normal conditions. Its musical
use might be thought of as a "fatness" control—it determines the overall "punch" of your
instrument. With passive instruments, this will be straightforward. With active instruments
containing bass-boost/cut functions, more exploration will be worthwhile. Remember, this control
can boost bass up to 15dB, so adjust it carefully.
The MIDRANGE control operates in a crucial area for most instruments. Many basses (particularly
ones with roundwound strings) can have a very "honky" or nasal sound. Dropping the MIDRANGE
control can go a long way toward smoothing out your tone. We suggest, though, that what sounds
best when you're listening to your tone by yourself may not be what works best when playing with
other musicians, or along with a CD when practicing. Use your ears to determine what you like best.
The TREBLE control operates in a tonal area that extends through and beyond the usual treble
control range. Over time, we have found this approach to result in a more "musically useful"
treble. Boosting the control will open up the sound of a dull instrument, especially one with dead
strings. However, this is also the range of string rattle, finger slides, pickup clicks, etc. Again, we
recommend you experiment with the control alone with your instrument while finding your tone,
and listen again when playing with other musicians or with a CD.
Tuner Out/Line Out Jack
This jack allows you to connect an instrument tuner to your L.A. Series amp without having to
unplug and go back and forth from amp to tuner to amp. Simply plug in a shielded patch cord
from this jack to the INPUT of your tuning device. Turn the amp on and you're ready to go. If you
don't want to monitor your sound while tuning, turn down the VOLUME control all the way. This jack
also functions as a "preamp out" jack. Simply connect a shielded patch cord from the TUNER OUT
jack to another power amp, or a powered monitor, or even a live mixing board or studio console.
The tone controls WILL affect the signal present at this jack.
Headphones Jack
By inserting a set of STEREO headphones into this jack, you will be able to monitor your sound or
practice without disturbing your neighbors. Once you insert the headphone plug into this jack, the
internal speaker system will automatically shut off.
The VOLUME control serves as the control for volume of the headphones as well. We suggest you
begin with the VOLUME control off (fully counter-clockwise), then slowly bring the volume up to your
desired level. If you hear some distortion in your headphones, turn down the VOLUME control.
You're probably overdriving your headphones and could ruin them through continued use in this
fashion (not to mention damage your ears in the process).
Any impedance stereo headphones will work. However, optimum impedance is 75 ohms.
Note: Do NOT use mono headphones as they could short out the system.
L.A. Series • 9