The First Things . . .
Speakers and Cabinets
Just because there are four speaker
jacks on your amp, that doesn't automatically mean
that you can plug in four speaker cabinets.
There is a definite right way and a WRONG way to connect speakers
and cabinets.
Speakers (and cabinets) are generally rated at 4, 8, or 16 ohms.
This is called their 'impedance'.
The term 'ohms' (impedance) is used to describe the 'load' that a
given speaker will put on the amplifier.
When you add more than one speaker or cabinet, there is a
mathematical formula to find the 'safe load'. (And some of you
thought that you'd
never need 'math' to play music! Surprise !!)
I'll give you some shortcuts, though.
No strained brains, please.
Let's say you just bought an amp with a 4 ohm 'minimum load'
rating.
That means you can connect speakers to a total of 4 ohms to it.
"How can I do that?" Glad you asked.
The formula for multiple speaker connections is as follows.
Divide the impedance (ohms) of the speakers by the number of
speakers that you want to use.
I think I sense some strained brains already.
Okay, here's the shortcut . . .
You have two 8 ohm speakers. 8 divided by 2 = 4.
So, what is the speaker load on the amp?
That's right, 4 ohms. Congratulations!
" Yeah, but I wanna run four cabinets." Okay, let's see . . .
four 8 ohm cabinets.
Ah ha! 8 divided by 4 = 2. Uh, oh. 2 ohms? " But the
amp says 4 Ohm minimum load! Now what? "
Well, here's where you need a technican. Ask him for a 4-way
breakout box.
This is a device that internally connects four speakers (or
cabinets) in such a way so as to ' fool ' the amp
into thinking there is just one 8 ohm load on it.
Here are some more shortcuts . . .
four 16 0hm speakers - 16 divided by 4 =
4.
four 4 ohm speakers - 4 divided by 4 = 1. ( Whoah, 1 ohm?!
)
two 16 ohm speakers - 16 divided by 2 = 8.
two 8 ohm speakers - 8 divided by 2 = 4.
Notice that in the
above examples, all of the speakers have the same impedance (ohms)
!
These examples WILL NOT WORK if the speakers are of different
values . . . .!
For instance, two 4 ohm speakers and two 16 ohm speakers, connected
to the same amp.
What now? Off to the tech for a breakout box.
If any of you would like to have a chart to make this even
easier,
send me an e-Mail and I'll send one out.
And, of course, if you don't pay attention to this,
well, you know what'll happen, right? 
Click here for a diagram of various speaker
wirings.
Gain vs. Volume
For the cleanest guitar
/ keyboard amp sounds,
run the Master (or volume) control somewhere between 75-90%.
Increase the control until you hear hissing or hum increase a lot.
That's the 'background noise' level.
Lower the control until the noise just goes away.
This is especially important in P.A. and recording situations.
(Although it's a little more involved with recording work.) Many
so-called 'engineers' run their masters well down and crank up the
channels.
Not only does this give a distorted output . . .
it also overloads the master section
circuits.
And when you overload a circuit long enough and hard enough,
well, guess what happens?
 'nuff said?
Running
distortion?
DO NOT use your
effects as "gain boosters"!!!
You can (and in all probability will) damage the input circuits in
your amp.
We see this all the time in the Service Department.
"... uh, yeah, I run four distortion boxes and two compressors, man
... uh", with all controls on '10',
putting about the same voltage into their amp .....
as if they hooked up twenty guitars in
series!
There should be only a small volume change between your
straight and FX sounds.
This idea goes back to the days of tubes.
It DOES NOT work well
with solid-state amps!
It was never very good for tubes, either.
Made for a much shorter life span for the pre-amp tubes. Remember,
the harder you drive them, the sooner they will need replaced!
Don't wait for a failure in your tubes. You know how hard you use
'em.
Keep them replaced regularly, to keep up your performance,
and more importantly,
to maximize the safety of your
amp.
DO NOT BUY CHEAP
CUT-RATE TUBES!!!
(Unless you
want(?) cut-rate performance !)
Equalization
EQ's are a subtractive device.
That means, they are for lowering certain frequencies in a pre-amp
or mixer.
THEY DON'T CREATE SOUNDS ON THEIR OWN! (How can you boost
something that isn't there?)
The 'smile face' you've all seen on EQ's only means -
that ... the 'engineer' has no clue as to how to use it.
No slider should ever be above '0"!
Anything over '0' adds noise!
This is extremely important in P.A. and recording
situations. Every mix or amp sound has too much of something
to start with. "...Too much bottom end ...",
"...too many(?!) high's ...", "... mids are honkin'
...".
Use an EQ to lower those trouble spots.
Result . . .
Cleaner sound, cleaner mixes, better sound.
Simple!
Plus, you're not wasting your power on sounds that you don't
want anyway.
And when you overload amps and speaker systems long enough and
hard enough, well, guess what?
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