SWR Baby Baby Blue Bedienungsanleitung Seite 19

THREE-POSITION TWEETER SWITCH
Located on the rear of the speaker cabinet section, this three-position slide switch allows you to choose
the mode of operation for the piezo tweeter. FULL will provide the full range, unattenuated signal through
the tweeter; –6dB will bring the tweeter level down slightly; and OFF will defeat the tweeter completely.
Note: If the Speaker On/Off Switch is set to "Off" the tweeter will be defeated along with the speak-
er, and therefore the tweeter switch will have no effect.
INTERNAL FEATURE: VACUUM TUBE (VALVE)
SWR installs a specially selected 12AX7A dual triode on the preamp circuitboard of every Baby Baby Blue.
If this tube needs replacing, we recommend that you replace it with a similar high quality product. This
tube will need replacing only if it becomes noisy or microphonic (which sounds like glass tinkling in the
background of certain notes), or completely fails (causing no signal or signal at very low levels). The tube
in your Baby Baby Blue should last one to three years, depending on usage.
A FEW WORDS CONCERNING HEAT
One of the most asked questions about our amplifiers is why they tend to get warmer than other amps.
The chassis of your amplifier can get quite warm during normal usage. This is especially true if you are
operating your Baby Baby Blue at a 2 or 2.6 ohm total impedance. This is because these low impedances
are introducing the least efficient condition of the unit (in terms of power drawn from the outlet in relation
to power produced in the speakers). The difference in these two figures can be as high as 300 watts. This
would be the equivalent of putting a 300-watt light bulb inside a metal box, which would obviously get
quite hot.
Most musical instrument amplifiers on the market today use steel for their chassis, which does not
conduct heat as well as aluminum. The Baby Baby Blue uses an all aluminum chassis and because it has
less impurities than steel, is less susceptible to rust, and is a better conductor of heat. This results in the
chassis acting as an additional heatsink, drawing heat away from heat-producing components inside and
thus extending their life. In this manner, we feel we have produced a more reliable amplifier, but at the
same time, the outside of the Baby Baby Blue will get warmer than cases made out of steel.
The one condition you should be aware of is if the power amplifiers in your unit becomes "over-biased."
This condition can be recognized by turning your amplifier on and letting it sit "idle" (without playing it). If
your unit starts getting hot under these conditions, it may be over-biased. This situation should be
attended to and can be easily remedied in about 15 minutes by a qualified service technician. A power
amp can become over-biased through continuous vibration or by any large jolt received in shipping, etc.
FINAL ENGINEERING SUMMARY
The two preamp gain stages utilize a specially-selected 12AX7A. The tone controls incorporate I.C.'s, and
the power amp is designed with extremely high quality bi-polar devices. Each type of device was chosen for
its performance and reliability in the application used. The chassis of the Baby Baby Blue comprised of
aluminum, because of its superior electrical and thermal characteristics and light weight. All primary
electrical components are U.L. approved, and SWR uses Beldon Cable for all shielded wire. All units are
assembled by hand and individually soundtested in the U.S.A. at our factory in Southern California.
BABY BABY BLUE • 19