SWR Amplifier POWER 750, Руководство пользователя

Страница: 8 / 12

8 • POWER 750
Here's another formula: To figure out the total impedance of two or more cabinets of equal value hooked up in parallel, divide the impedance of
one cabinet by the number of cabinets:
Impedance of one cabinet / number of cabinets = total impedance
(For an even more in-depth discussion of impedance and power rating issues, go to the SWR Website at www.swrsound.com, click on "Press", then
click on "Articles", then click on "Plug and Play - Setup Tips for Amps and Speakers" - an article by SWR founder Steve Rabe that ran in the August
'92 issue of Bass Player Magazine.)
POWER 750 POWER DELIVERY CAPABILITIES (POWER RATINGS)
After determining how the number of cabinets you wish to run affects the total operating impedance, you need to take into account the power han-
dling capabilities of your speaker cabinets as compared to what the Power 750 can deliver at that impedance. Those ratings are as follows:
850 watts @ 2.6 ohms
750 watts @ 4 ohms
450 watts @ 8 ohms
So if you have two 8 ohm speaker cabinets, they will each get up to 375 watts of power, and more during transient peaks. A single 4 ohm cabinet
will get up to 750 watts of power. Make sure your speaker cabinets can handle the horsepower!
This is even more crucial when running at the minimum impedance. When operating your Power 750 at 2.6 ohms, the combined power handling of
your 4 ohm and 8 ohm cabinet had better be at least 850 watts. To be safe, each individual cabinet (especially the 4 ohm cabinet) should handle
at least 500 watts. Don't guess or assume that your speaker cabinets can handle the power listed above - get the specs and make sure!
Also be aware that when running the Power 750 at 2.6 ohms, you are operating at the maximum capacity of the power amplifier. If you're sending
too hot a signal from your preamp, and your Power 750 Volume control is set high as well, you may hear audible clipping of the power amp (and
the +3 Red LED on the front panel should be glowing). If so, you have exceeded the maximum capacity of the power amp. Continual clipping of the
power amp section can cause damage to the power amplifier and/or your loudspeakers.
Remember, it's always better to have a little too much power than just barely enough. If you find yourself constantly wanting more power than the
Power 750 provides, either:
a) ask your bandmates to turn down
b) ask the monitor engineer to turn you up
c) (best option) take the time to investigate getting another external power amp and/or additional speaker cabinets to supplement your system
NOTE: The frequency response of the Power 750 is far greater than usually found in musical instrument amplifiers (20 Hz to 40 kHz). This was
engineered in order to give the bass player the same punch and clarity on stage as found in the studio or concert P.A. systems. Therefore, it is
doubly important that you are aware of the impedance and power rating of the speakers that you intend to use, and that they are compatible with
the Power 750.
Speakers that have been overdriven are easy to detect and generally do not fall under manufacturer warranty.
SPEAKER OUTPUT JACKS
There are two 1/4" jacks and two Speakon jacks provided for the output section of the Power 750. Make sure all speakers are properly connect-
ed BEFORE turning on the Power 750 whenever possible. Generally it's a bad idea to plug or unplug your speakers while the unit is on.
SPEAKON VS. 1/4" JACKS
We have found the Speakon connection to be superior in both stability and amperage conductivity, and so we have provided Speakon output jacks
in addition to the standard 1/4" jack. If using the Speakon output jack, we highly recommend the use of a Speakon-to-Speakon speaker cable, one
of which is supplied with your unit. (All SWR Professional Series speaker cabinets manufactured after January of 2000 come equipped with
Speakon input jacks.) If your speaker cabinet(s) does not have a Speakon input jack, you should use the 1/4" output jacks on the Power 750 and
connect them accordingly. The Speakon jacks are wired "standard" (+1/-1) and additional Speakon-to-Speakon cables are available through most
musical equipment retail outlets.