Egnater Rebel-30 Head, Руководство пользователя, Страница: 12 / 16

REBEL-30 HEAD
There is some confusion about the
relationship between watts and volume
(loudness). There is much discussion
about how this many dB is twice as
loud as that many and that many dB is
double the power and blah blah……
lot’s of techie rambling but no real world
explanations. I’ll try. Let’s say you have
a guitar amp with a knob to adjust the
power (watts). Now say this amp is 20
watts at its maximum power setting and
1 watt at the lowest knob position. It
would be reasonable to assume that 20
watts should be loud enough to play with
the band and 1 watt would be whisper
volume. Anyone who has had the op-
portunity to test this theory has found
quite the contrary. 20 watts through a
reasonably efficient speaker is quite
loud. 1 watt through the same speaker
is also quite loud. What’s up with that?
Have you ever seen the specs for a 12”
speaker? A typical guitar speaker will
produce about 95 to 100dB at 1 meter
(about 3.3ft) with 1 watt of input power.
Now put 2 or 4 of that same speaker in
a cabinet and the output is even higher.
What this is saying is that even with a
mere 1 watt of power, that speaker will
put out the volume about equal to a per-
son yelling. Obviously not “TV watch-
ing” volume. To obtain that whisper
volume, you might need as little as 1/10
of a watt but…….at that low a volume,
most guitar speakers start to sound ter-
rible. In addition, there is a phenomenon
that occurs with human hearing that is
documented by Fletcher and Munson
(two really smart guys) that graphs the
way we hear things at different volumes.
Look it up on the internet. The Fletcher/
Munson curves show how our ears, at
lower volumes, are less responsive to
low and high frequencies. That means
the quieter you play, the more we tend
to want to boost the bass and treble to
compensate for our own hearing. Ever
seen the “loudness” contour switch on
a home stereo? That is what the switch
does. It boosts the treble and bass to
make it sound better quiet. On a guitar
amp you often find knobs for boosting
the low and high end in the power amp
section. Typically these controls are
called Presence for the high end boost
and Resonance or Depth or Density (Eg-
nater) for the low end. At low volumes
you typically turn those controls up but
the louder you play, the more you find
you need to turn them down. Fletcher/
Munson again.
Because we make guitar amps with
variable power (Rebel) and switch-
able power (Tourmaster and Modular),
we get inquires about this all the time.
Often players will use one of our amps
and it appears that the power cut feature
doesn’t do much. Please allow me to
explain.
Let’s say you are playing an amp
at home or in a music store at relatively
low volume. Recall what was said ear-
lier about how little power it really takes
to get a fairly loud volume. If you’re
playing quiet, you might be using even
less than 1 watt to obtain the loudness
you’re at. If you have a chance, try this
on a Rebel. Play fairly quiet and turn the
WATTS knob from 20 watts to 1 watt.
What do you hear? Very little change!
Why? Because at that volume you prob-
ably are not even using up 1 watt let
alone 20 watts. Sort of like driving a car
at 5MPH. It doesn’t matter if the engine
is a 100HP or 500HP, you are still only
going 5MPH and using very little HP
to maintain that speed. Same with your
amp. To cruise along at low volume
requires very little power (watts). Hav-
ing the extra horsepower (watts) doesn’t
make the amp louder when you play at
low to medium volume.
Now try this with your Rebel. Set
the power to 20 watts, turn the master
full up and turn up the gain knob until
you start to hear some distortion. It will
be loud. While you’re playing turn the
WATTS knob down. You will clearly
hear and feel the way less power creates
a spongier, lower volume tone. Some
players are saying the knob isn’t really
cutting the power but is reducing the
headroom. Call it what you will, the re-
sult of reducing power is more of a “feel
thing” than a volume thing. Ultimately
the idea is to set it to where you like the
sound and be happy…..play your guitar.
While we’re on the subject of the Rebel,
there has been some talk about how,
when panning from the 6V6 tubes to the
EL84 tubes, the tone difference is not
what some expected. It is believed that
by simply changing power tubes you can
make a Fender (6L6 power tubes) sound
like a Marshall (EL34 power tubes) or
a Vox (EL84 power tubes). What you
are hearing in the Rebel when you go
from 6V6 to EL84 is the real differ-
ence in the sound of those two types of
tubes. It may not be quite as dramatic
as many believe but that is the reality of
it. The tonal difference between vari-
ous types of tubes is more subtle than
many believe. A few people have even
been disappointed when using the TUBE
MIX features because their expectations
of what should happen were really not
based in fact. The intangible charac-
teristic is the change in “feel” between
different types of tubes. These subtle
differences do become more apparent at
higher volume when the power tubes are
“pushed” a little more into overloading.
What you are hearing in the Rebel is
“the truth” about power tubes.
TECH NOTE #101 WATTS vs VOLUME and other stuff….
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