SWR 750x

(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.)
750x 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 handling capabilities of your speaker cabinets as compared to what
the 750x 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 750 watts of power, and again, more during peaks. Make
sure your speaker cabinet(s) can handle the power!
Also be aware that when running the amp at 2.6 ohms, you are operating at or near the maximum capaci-
ty of the power amplifier. With extreme settings on the Gain and Master controls, you may hear audible
clipping of the power amp. If so, you have exceeded the maximum capacity of the power amp. POWER
AMP CLIPPING CAN CAUSE DAMAGE BOTH TO ITSELF AND YOUR SPEAKER CABINETS. If this occurs,
back off on the Gain and Master controls, and/or engage the Variable Limiter at a higher setting.
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 750x provides, either:
a) Tell your bandmates to turn down
b) Tell the monitor engineer to turn you up
c) (best option) Take the time to investigate getting an external power amp and/or additional
speaker cabinets to supplement your rig.
Question: Can you safely daisy-chain an 8 ohm speaker cabinet and a 4 ohm speaker cabinet together even
though they have different impedances? Yes, but one speaker cabinet will get more power—and be louder—
than the other. Since your 750x is a mono amplifier, it is best to use cabinets of similar impedances when
using more than one. The best two-cabinet setup is to use two 8-ohm enclosures.
Note: The frequency response of the 750x is far greater than usually found in musical instrument ampli-
fiers (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 PA. 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 com-
patible with the 750x. Speakers that have been overdriven are easy to detect and generally do not fall
under a manufacturer’s warranty.
Speaker Output Jacks
Two 1/4" phone jacks and two Speakon jacks (all wired in parallel) are provided for connection of the 750x
to your speaker system. Whenever possible, use of the Speakon jacks is recommended. Speakon jacks and
connectors offer the best possible connection and are far superior to banana or 1/4" phone jacks in that
they not only lock in place (preventing accidental disconnection), but also offer a greater and more stable
connection surface. This solid connection provides a more effective transfer of power to your speakers.
Only SPEAKER CABLE of 18 gauge or heavier (the heavier the cable, the lower the gauge) should be used
to connect your 750x to your speaker system. Do not use shielded instrument cable to connect your ampli-
fier to your speaker enclosure, as this can result in intermittent power loss, cause your amp to oscillate
and damage itself and/or your speakers, and render the cable useless for any purpose.
Note: Unlike most amplifiers on the market, the 750x can be used for recording purposes without speak-
ers attached to the speaker output jacks (using only the Balanced [XLR] Output).
Recommended single SWR Speaker enclosures for use with the 750x include:
• Megoliath 8x10
750x OWNER’S MANUAL • 15