PA 101

Introduction to PA 101

Greetings and Salutations from Hank at Owensboro Music Center. Over the coming months myself and the staff (Bruce and Lewis) will be giving some tasty little tips on the basics of PA. We’re going to start this off with a very basic concept that over the years seems to be one that is hard for the average consumer to grasp. Series versus parallel in speaker wiring. One easy way of looking at this is Christmas tree lights. If a strand has one bulb go out, and the whole strand goes out, this is series wiring. If a strand has one bulb go out, and ONLY that bulb is out, this is parallel wiring. So to apply this to speaker application, speakers wired in series will RAISE the impedance that the amp sees. Also, if one speaker fails, the entire cabinet, or circuit, will stop. 8 ohm + 8 ohm = 16 ohms. This circuit is wired as follows; positive connection from the jack is connected to a positive connection on speaker one, negative connection on speaker one is wired to positive connection on speaker two. Negative connection on speaker two is wired to negative connection on the jack.

Speakers wired in parallel will lower the impedance load that the amp sees. If a speaker fails it will not stop the entire circuit, only change the impedance load. 8 ohms + 8 ohms = 4 ohms. This circuit is wired as follows; Positive connection from jack is connected to positive connection on BOTH speakers. Negative connection from jack, is connected to negative on BOTH speakers.

This is a simple concept (easy for us to say as we’ve been doing this for 40+ years), but is very critical for the safety of amplifiers. We hope this sheds some light on a very simple but age old problem and we’ll have a few more tasty little tidbits coming in the near future! (Parallel vs. bridging on power amplifiers)

Hank Starks,

Owensboro Music Center, MSO Member

RA Campbell webmaster