Maybe im ignorant (no comments please), but what exactly does the amplifer
amplify? Is the musical signal (in the form of an analog sine wave from the
preamp) then "amplified" by the transistors to just a stronger more powerful
identical signal so that it can be transduced to air pressure by the speakers?
What parts of the amplifier actually boost the incoming signal and how does the
transformer accomplish this? Thanks. -Bob Bernstein.

On Thu, 08 Jan 2004 16:45:31 +0000, RBernst929 wrote:

Maybe im ignorant (no comments please), but what exactly does the amplifer
amplify? Is the musical signal (in the form of an analog sine wave from
the preamp) then "amplified" by the transistors to just a stronger more
powerful identical signal so that it can be transduced to air pressure by
the speakers? What parts of the amplifier actually boost the incoming
signal and how does the transformer accomplish this? Thanks. -Bob
Bernstein.

The simplest description of an amplifier is that it makes a bigger copy of
a small signal. If you've ever seen or used a pantograph drawing tool
where tracing a shape makes a bigger copy to the side, that is basically
amplification.

The power supply section of the amplifier takes electricity from the wall
socket and converts it to a suitable voltage as required by that
particular amp's design.

The small input signal from the preamp (or tuner/CD/whatever) is then used
to modulate or control the available electricity from the power supply. In
other words, if your input signal was a 0.5 volt 1000 Hz sine wave, the
amp uses that signal to control the available power to make, for example,
a 5 volt copy of a 1000 Hz sine wave. (This process is usually done in two
or three steps (or stages) inside the amp.

Transistors or tubes are the parts control the amplification process. A
transformer (if used) in the output matches the output voltage to what is
needed by the speaker. (Tubes, for example, put out a high voltage, but
low current signal. Speakers don't need that much voltage, but do need
more current. The transformer makes that conversion, but doesn't acutally
amplify by itself.)

There are obviously a lot more details to this than noted, but maybe this
will give you an idea.

In britain tubes are called valves, which gets us to answering your
question, a dandy. Current comes from the power supply at a particular
voltage. Ther is a max and a min level of it. The output devices, tube
or ss, act as a control valve determining how much between the min and max
is passed on to the speakers. The analog signal coming into the amp
controls the "handle" of the "valves" by turning them on more or less in
proportion to the analog signal. If the input signal goes up, it "opens"
the "valve" more and closes it as signal decreases. The output signal to
the speaker is amplified,ie. at higher levels, as the input signal
modulates the amp's power supply output. Forgive this oversimplification,
but I hope you get the idea.

Maybe im ignorant (no comments please), but what exactly does the amplifer
amplify? Is the musical signal (in the form of an analog sine wave from the
preamp) then "amplified" by the transistors to just a stronger more powerful
identical signal so that it can be transduced to air pressure by the speakers?
What parts of the amplifier actually boost the incoming signal and how does the
transformer accomplish this? Thanks. -Bob Bernstein.

The amplifier amplifies the musical signal. It simply makes it bigger.
You can connect your CD player directly to your speakers, and you will
hear something, but it will be infinitely small in sound level. I think
a good simple analogy as to how an amplifier works is that there are 2
transistors. One transistor is reading the music signal coming in, and
varying its current according to the signal. The other transistor, a BIG
one, is 'watching' the first transistor, immitating its every move, but
on a larger scale. The 1st transistor swings 1A to the left, the BIG
transistor then swings 10A to the left etc. The transformer's job inside
the amplifier is to provide the electrical power to the transistors and
that's it. A really good transformer will do that, completely unwavering
in its steady state electrical properties, like it's voltage. Lastly,
the BIG transistor is really a whole bunch of small transistors acting
as one big one.

CD

RBernst929 wrote:

Maybe im ignorant (no comments please), but what exactly does the amplifer
amplify? Is the musical signal (in the form of an analog sine wave from the
preamp) then "amplified" by the transistors to just a stronger more powerful
identical signal so that it can be transduced to air pressure by the speakers?
What parts of the amplifier actually boost the incoming signal and how does the
transformer accomplish this? Thanks. -Bob Bernstein.