SWR Sound 750x Musical Instrument Amplifier User Manual


 
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 capacity
of the power amplifier. With extreme settings on the Gain and Master controls, you may hear audible clip-
ping 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 loud-
er—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
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 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 compatible 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 amplifier
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
speakers attached to the speaker output jacks (using only the Balanced [XLR] Output).
750x OWNER’S MANUAL • 15