distortions in amplifiers

[adam k]

if i was to build an amplifier what are the main types of distortion
you think i will come across and what could be done to reduce or avoid
them

 

[Henry Kolesnik]

That's a question that can be answered by getting degrees in EE, not a
simple question to answer, many test have been written on this subject and
still being written. On the other hand there's the vacuum tube guys who
like ceratain kinds of distortion! Go figure.
hank wd5jfr
"adam k" <adamkurasz@hotmail.com> wrote in message
news:648e36e6.0312030650.41fc4584@posting.google.com...

if i was to build an amplifier what are the main types of distortion
you think i will come across and what could be done to reduce or avoid
them

 

[Baphomet]

"Henry Kolesnik" <wd5jfr@oklahoma.net> wrote in message
news:vss53r99hm0e35@corp.supernews.com...

That's a question that can be answered by getting degrees in EE, not a
simple question to answer, many test have been written on this subject and
still being written. On the other hand there's the vacuum tube guys who
like ceratain kinds of distortion! Go figure.
hank wd5jfr

Warmth...if you please ;-)

 

[CFoley1064]

if i was to build an amplifier what are the main types of distortion
you think i will come across and what could be done to reduce or avoid
them

Hi, Adam. A pretty good basic answer to your question is contained on the

following web page:

http://www.rocketroberts.com/techart/amp.htm

Try Googling audio distortion for more.

If you want a good answer, you should give more information, but...

As a beginner, you might want to go with one of the many kits that are
available for audio (I assume) amplifiers. There are a wide variety in many
price ranges. If your soldering and construction skills are a little light,
get one of the less expensive kits to start with. Measuring distortion usually
requires some pretty expensive equipment, which the home hobbyist doesn't have.
Also, there's quite a bit of math and electronics theory behind designing a
good low distortion amplifier, as well as various pitfalls in construction,
layout, &c. It might not be a good place to start.

Good luck.
Chris

 

[Bob Masta]

On 3 Dec 2003 06:50:58 -0800, adamkurasz@hotmail.com (adam k) wrote:

if i was to build an amplifier what are the main types of distortion
you think i will come across and what could be done to reduce or avoid
them

Assuming you mean a power amp and not a preamp, there are a few
general concepts. One of the nastiest types is crossover distortion,
which happens in push-pull output stages when there isn't enough
bias; there is a gap where a sine wave goes to zero, stays there until
the other half of the push-pull starts conducting, and then resumes.
It makes lots of odd-order hamonics, but the real problem is that it
is worse (as a percentage of signal) at lower levels.

At high levels on any amp you can get clipping distortion if you
overdrive it, which is odd-order and generally unpleasant.
(Well, unless you are into heavy-metal guitar, exclusively!)

On any amp with top-bottom asymmetry, such as anything
that is *not* push-pull, you tend to get more even-order
distortions. The golden-ears crowd is fond of Class A
amps, which exhibit tons of distortion (few percent) but
they like the more pleasing sound of even-order harmonics.

Then there is slew distortion, where the sharp vertical
edges of square waves can't be followed fast enough, so
you get trapezoids or triangles instead.

Any of these distortion types can/will also cause intermodulation
distortion, where an input of two tones gives not just
the orginals and their harmonics, but also "inharmonics"
based upon the sum and difference. Nasty sound, since
the new frequencies are unrelated to the note being played.

And on, and on......



Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

 

[JeffM]

if i was to build an amplifier what are the main types of distortion
you think i will come across and what could be done to reduce or
avoid
them
adam k

many test have been written on this subject and still being written
Henry Kolesnik

and once you know what theoretical levels of distortion might exist,
how do you plan to verify the actual levels which you get?
http://www.google.com/search?num=100&hl=en&lr=lang_en&ie=UTF-8&oe=UTF-8&q=HP-331A+used+%22distortion+analyzer%22+price&btnG=Google+Search

 

[Ian Bell]

JeffM wrote:

if i was to build an amplifier what are the main types of distortion
you think i will come across and what could be done to reduce or
avoid
them
adam k

many test have been written on this subject and still being written
Henry Kolesnik

and once you know what theoretical levels of distortion might exist,
how do you plan to verify the actual levels which you get?

http://www.google.com/search?num=100&hl=en&lr=lang_en&ie=UTF-8&oe=UTF-8&q=HP-331A+used+%22distortion+analyzer%22+price&btnG=Google+Search

Douglas Self wrote and excellent series on this topic in Wireless World.
Just do a google search for him and you will be enlightened.

Ian