SPEAKERS AND IMPEDANCE
Every guitar amplifier actually consists of two primary parts: amp and speaker. In
combos, the speaker has already been matched to the amp. Since the JCA22H is only
the amp, you will need to connect it to suitable speakers. There are some basic
ground rules for this.
1.
What are the best speaker cabinets for my JCA22H?
Why, Jet City cabinets, of course! The single speaker JCA12S, dual speaker
JCA24S, and quad speaker JCA48S were all designed to get maximum tone
out of our amps.
2.
What is “impedance” and why is it important?
Every speaker cabinet has an impedance rating listed in ohms. Think of the
impedance as the speaker cabinet’s resistance to an amp’s power. The
higher the cabinet’s impedance, the more the amp has to work to push
power through it. The goal in any amp/cabinet configuration is the match
the amp’s speaker output impedance with a speaker’s impedance
(sometimes called “load”).
3.
OK, how does that relate to my JCA22H?
Your amp has outputs on the back marked “16 ohm” and “8 ohm.” You
need to pick the correct output for your speaker configuration. To be
specific, if your speaker cabinet is listed as “16 ohms” then use the “16
ohm” output on your JCA22H.
Things get a bit more complicated when you want to use more than one
speaker cabinet. Speaker cabinets often have a set of ¼” jacks labeled
“series” or “parallel.” This allows you to run a speaker from your head to
one cabinet and then from that cabinet to another one. When you use the
“series” output, the load increases so you add each cabinet’s impedance to
determine the overall load (two 8-ohm cabs in series = 16-ohm load).
When you use the “parallel” output, the load decreases. If all cabinets have
the same impedance, then divide that impedance by the number of
cabinets (two 8-ohm cabs in parallel = 4-ohm load). If the cabinets are of
different impedance, then multiply the impedances together and divide this
by the sum of the cabinet impedances (one 8-ohm cab and one 16-ohm cab
in parallel = 5.33-ohm load). In case of an awkward number, default to the
impedance closest to, but lower than, the number (for a 5.33-ohm load, use
the 4-ohm output).
