Tapco pmn Manuel D’Utilisation

Appendix B: Technical Info

An ohm is a unit of resistance — the more ohms, 

the more resistance (or, more accurately in this case, 
impedance). The more the resistance, the less the 
power.

If you’re dealing with just one speaker (or cabinet) 

per output, the load in ohms is usually printed on it 
somewhere. That’s your load, usually 8 ohms or 4 
ohms.

If you’re driving an assortment of speakers, 

things can get complicated. There are two basic 
ways of linking multiple loads (or speakers in this 
case): series and parallel.

Since series connections are not normally used 

in PA applications, we’ll concentrate on the parallel 
connection. Parallel means that the positive amp 
output connects to the positive terminals of all the 
speakers, and the negative amp output connects 
to the negative terminals of all the speakers. If one 

speaker fails in a parallel configuration, the others 
will still work.

Calculating parallel loads is easy, as long as 

each speaker has the same value — just divide the 
value by the number of speakers. For instance, four 
8-ohm speakers, connected in parallel, will equal 2 
ohms (8/4 = 2). If the loads are not all the same, the 
formula gets a little more complicated, but nothing 
that you can’t do with a simple calculator.

ZT = 

1

1

Z1

+ 1

Z2

+ 1

Z3

+ . . .

Using this formula, an 8-ohm speaker and a 4-

ohm speaker, connected in parallel, will equal 2.7 
ohms. Remember that the Juice amplifiers require 
2 ohms or greater per channel in Stereo or Mono 
mode, and 4 ohms or greater in Bridge mode.