Mesa/Boogie II - Manual (Page 25)

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SPEAKER IMPEDANCE MATCHING & HOOK-UP GUIDE:
IMPEDANCE:
Wiring up speakers to provide the most effective load and making sure that all of them are in phase will help in
creating the best sound possible. This is not too diffi cult, as long as you understand a few things about loading and how to connect
your speakers to provide an optimal resistive load.
MESA/Boogie amplifi ers can handle 4 and 8 ohms effectively. Never run below 4 ohms in a tube amplifi er unless you are absolutely MESA/Boogie MESA/Boogie
certain that the system can handle it properly; this can cause damage to the Output transformer. A few amplifi ers can handle 2 ohms
effectively without damaging them ( for example the MESA’s Bass 400+). You can always have a higher resistance (16 ohms, for
example) without damaging results, but too low of a resistance will likely cause problems.
MIS-MATCHING:
When running a higher resistance ( for example: 8 ohm output into 16 ohm cabinet ), a slightly different feel and
response will be eminent. A slight mismatch can provide a darker smoother tone with a little less output and attack. This response is
a result of the amplifi er running a bit cooler. Sometimes when using more than one cabinet a mismatch will be the only option.
WHAT IS MY CABINETS IMPEDANCE:
If you have only a single speaker, you just match that single speakers impedance to
the amplifi er, and you are done. In many cases, you will have a number of speakers, and then you must calculate the “load” that the
amplifi er will need to support. There are generally three ways to wire multiple speakers together. They are as follows:
SERIES:
When you wire ( hook-up ) speakers in Series, the speakers resistance ( as measured in ohms ) is additive - i.e. putting
two 8 ohm speakers in Series results in a 16 ohm load.
Speaker A = 8 Ohms Speaker B = 8 Ohms
SERIES: Connect the Negative side of Speaker A
to the Positive side of Speaker B
POSITIVE = NEGATIVE =
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