SWR Mo' Bass, Owner'S Manual

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Speaker Output Section (Speaker Outs)
This section of the manual will deal with the proper connection of speaker cabinets to the power amplifiers in the Mo' Bass.
Some of this ground has already been covered in the Getting Started-Connecting Your Speaker Cabinets section in the
beginning of the manual. This is meant to supplement that section and provide information in greater detail, as power ampli-
fiers, impedance and speaker cabinets are all crucial in determining how best to operate your new Mo' Bass.
Power Amp Assign Switch
The position of the Power Amp Assign Switch determines the Mo’ Bass power amp mode of operation. If you wish to run
your amplifier in the stereo mode, move the Power Amp Assign Switch to the "Stereo" position. Operation in the
bridged/mono mode is achieved by setting the Power Amp Assign Switch to the "Mono" position. Remember to change the
switch when you change modes of operation!
Choosing Your Setup
How do you know when to run in stereo and when to run in mono? It depends on three factors:
1. The number of cabinet(s) you wish to use
2. The impedance of the cabinet(s) you wish to use
3. The power handling of the cabinet(s) you wish to use
How Impedance Affects Power Ratings
People often have questions about impedance. What is it? The root of the word "impedance" is the verb "impede", which
means to block or resist. That's what impedance is - resistance to power.
Power amps do not have a pre-determined impedance. They deliver power at whatever impedance the speaker cabinet tells
it to. That's why you hear the term "slave amp" - amplifiers only do what they're told. So if someone tells you that they have
a "4 ohm power amp," their terminology and understanding of the concept is way off the mark.
Unlike power amps, every speaker cabinet has a pre-determined impedance rating measured in "ohms." In most cases this
rating is either 4 or 8 ohms (though there may still be some old 2 ohm creakers out there). The higher the impedance of the
speaker cabinet, the more resistance to power it will offer. The lower the resistance of the speaker cabinet, the less
resistance to power it will offer. In other words, HIGHER IMPEDANCE MEANS LESS POWER CAN ENTER THE
SPEAKER CABINET. LOWER IMPEDANCE MEANS MORE POWER CAN ENTER THE SPEAKER CABINET.
You may be thinking that you've found the solution to the universe - just use speaker cabinets with really low impedances
and you can get skull-crushing power out of your amplifier, right? Wrong. There's a catch. Power amps have limits as to
how low an impedance they can drive safely. This is what's known as an amplifier's "Minimum Impedance Rating." If you try
and operate a power amp below its minimum impedance rating, it will give you lots and lots of power for about five min-
utes...and then overheat, short out and fail completely. In other words, THE LOWER THE OPERATING IMPEDANCE OF
THE AMPLIFIER, THE HOTTER IT WILL GET.
Mo' Bass Power Amplifier Minimum Impedance Ratings
Here's what this means to the power amp in the Mo' Bass. As mentioned previously there are two power amps in the Mo'
Bass, which can be run in stereo mode or bridged into a mono-block configuration. Let's discuss running in Stereo Mode
first. The Minimum Impedance Rating of the Mo' Bass in the Stereo Mode is 2 ohms per side. This means that you can
connect:
• One 2 ohm speaker enclosure per side
• Two 4 ohm speaker enclosures per side
• Four 8 ohm speaker enclosures per side
The Minimum Impedance Rating of the Mo' Bass in the Bridge/Mono Mode is 4 ohms. This means that you can connect:
• One 4 ohm speaker to the Bridge/Mono Output
• Two 8 ohm speaker enclosures to the Bridge/Mono Output
• Four 16 ohm speaker enclosures to the Bridge/Mono Output
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