Audio clipping/distortion cause?

[John Robertson]

What is the cause of audio clipping in a transistorised amp? Is it a
underpowered transformer not providing enough voltage/current to the
transistors, too much voltage/current to the transistors, or the transistors
themselves need higher voltage/has too much voltage (not transformer fault)? Or
something totally different?

I keep reading about amps getting into "overdrive" which causes the clipping,
but don't understand what this is. I have also read that valve amps have a more
soft clipping, while transistorised amps have a more hard clipping. Is this
correct?

If it is something as simple as a transistor getting too much voltage/current,
couldn't one then just lower the voltage/current to the transistor to stop or
at least lower the amount of clipping/distortion?

 

[Lord Garth]

"John Robertson" <robertson@voicenet.remove.com> wrote in message
news:vpcnrvga7priqtrd92fcrbppled8jvme3a@4ax.com...

What is the cause of audio clipping in a transistorised amp? Is it a
underpowered transformer not providing enough voltage/current to the
transistors, too much voltage/current to the transistors, or the
transistors
themselves need higher voltage/has too much voltage (not transformer
fault)? Or
something totally different?

I keep reading about amps getting into "overdrive" which causes the
clipping,
but don't understand what this is. I have also read that valve amps have a
more
soft clipping, while transistorised amps have a more hard clipping. Is
this
correct?

If it is something as simple as a transistor getting too much
voltage/current,
couldn't one then just lower the voltage/current to the transistor to stop
or
at least lower the amount of clipping/distortion?

If the gain x Vin is greater than the available power supply, you get
clipping.
You can lower Vin or lower the gain and you could resolve the problem
unless that form of distortion is desired as in an effects pedal.

 

[John Robertson]

On Wed, 19 Nov 2003 19:43:26 GMT, "Lord Garth" <LGarth@Tantalus.net> wrote:

"John Robertson" <robertson@voicenet.remove.com> wrote in message
news:vpcnrvga7priqtrd92fcrbppled8jvme3a@4ax.com...
What is the cause of audio clipping in a transistorised amp? Is it a
underpowered transformer not providing enough voltage/current to the
transistors, too much voltage/current to the transistors, or the
transistors
themselves need higher voltage/has too much voltage (not transformer
fault)? Or
something totally different?

I keep reading about amps getting into "overdrive" which causes the
clipping,
but don't understand what this is. I have also read that valve amps have a
more
soft clipping, while transistorised amps have a more hard clipping. Is
this
correct?

If it is something as simple as a transistor getting too much
voltage/current,
couldn't one then just lower the voltage/current to the transistor to stop
or
at least lower the amount of clipping/distortion?

If the gain x Vin is greater than the available power supply, you get
clipping.

By this, do you mean if the voltage input requirement for the transistor is
higher then what the power supply can supply, that the clipping will occur?

You can lower Vin or lower the gain and you could resolve the problem
unless that form of distortion is desired as in an effects pedal.

I'm not really understanding what you are saying, I'm sorry. I'm new to
electronics and trying hard to understand. It sounds like you are saying to
lower the voltage inputted to the transistor, will result in the clipping to
stop (or at least be reduced), but also that the requirement of the transistor
for voltage is more then what the transformer can put out.

For example, the transformer puts out 6 volts, but the transistor requires 9
volts, so because it's not getting 9 volts, the clipping is occuring. Is this
what you mean?

 

[Lord Garth]

"John Robertson" <robertson@voicenet.remove.com> wrote in message
news:0i3rrv4sn383vdfaa08vhhe9n05e7r2nkt@4ax.com...

By this, do you mean if the voltage input requirement for the transistor
is
higher then what the power supply can supply, that the clipping will
occur?

You can lower Vin or lower the gain and you could resolve the problem
unless that form of distortion is desired as in an effects pedal.

I'm not really understanding what you are saying, I'm sorry. I'm new to
electronics and trying hard to understand. It sounds like you are saying
to
lower the voltage inputted to the transistor, will result in the clipping
to
stop (or at least be reduced), but also that the requirement of the
transistor
for voltage is more then what the transformer can put out.

For example, the transformer puts out 6 volts, but the transistor requires
9
volts, so because it's not getting 9 volts, the clipping is occuring. Is
this
what you mean?

It is a bit tough but a transistor by itself is no more an amplifier than a
CPU
by itself is a computer. This means that if a circuit is designed to a
particular job
and if you try to make it more that the design is capable of, you will get
distortion.
That distortion is called 'clipping'.

An amplifier usually outputs a bigger, faithfully reproduced copy of its
input.
If a sine wave of 1 volt is the input and the gain is 10, the output should
be a
sine wave of 10 volts...suppose the power supply is only 9 volts...the
output
would be fine from 0 to 9 volts but from there, it could do no more, the
output
is at maximum and so the area that would be from 9 volts to 10 volts would
be 'clipped' off.

Suppose now the input is a sine wave of .5 volts, the gain of 10 would
produce
an output of 5 volts and all would be well with a 9 volt power supply.

Suppose the input was again a 1 volt sine wave but the gain was 8, the
output
would be an 8 volt sine wave and again, all would still be well.