This is NOT OK! The power amp will eventually overheat and fail. 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 "Support", then click on "Technical 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.) WORKINGMAN'S 2X10C POWER DELIVERY CAPABILITIES (Power Ratings) After determining how the extension cabinet you wish to use affects the total operating impedance, you need to take into account the power handling capabilities of that speaker cabinet as compared to what the Workingman's 2x10C can deliver at that operating impedance. Those ratings are as follows: 260 Watts @ 8 ohms (internal speaker system only) 400 Watts @ 4 ohms (internal system with one 8 ohm extension cabinet) So if you use an 8 ohm extension speaker cabinet along with your internal speaker system, it will get up to 200 watts of power (400 watts split in half), and more during transient peaks. Make sure your extension speaker cabinet can handle the power. There is also the situation known as underpowering your speakers. This is caused when the power amp, in the process of trying to drive one or more speaker cabinets, reaches its limit and goes into clipping. That "clipped" waveform (or "square wave") will quickly heat up the voice coils in speakers, and if operating continually while clipping, eventually will burn the voice coils and cause the speakers to fail. Speakers abused in this fashion are easy to detect and generally not covered under a manufacturer's warranty. (Remember, engaging the Limiter will not allow the power amp to clip, so we recommend that you not disengage the Limiter when running at low total impedances in general.) Also be aware that when running the amp at 4 ohms, you are operating at the maximum capacity of the power amplifier. With extreme settings on the Gain and Master controls and the Limiter circuit disengaged, 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. Either re-engage the Limiter (by pushing in on the Limiter control) to help smooth out the peaks, or back off on the Gain and Master controls. 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 Workingman's 2x10C provides, either: a) tell your bandmates to turn down b) tell the monitor engineer to turn you up c) (better option) take the time to investigate getting an external power amp for the additional speaker cabinets to supplement your rig d) (best option) investigate getting a larger rig (perhaps something modular, with a large head and two speaker cabinets) for those gigs where more power and volume is needed
