"Pooh Bear" wrote in message
...


" wrote:

What about the use of modern materials to reduce cone break up ?

Not to mention in all aspects of engineering - the use of CAD / somputer
modelling to optimise designs

Yikes.... I have a 1969-executed-in-1971 design sitting on my bench
with "true complementary pair" outputs.

That would be a very early example indeed. Sadly not of much help given
the
following info.

That it also used interstage
transformers and other Jurassic-vintage throwbacks is not relevant to
your statement.

Actually it is. It shows that such Jurassic designs were still being
implemented in 1971 ! Kinda blows that 'no advances in the last 35 yrs'
claim
out the window nicely !

Check this one out:

http://users.ece.gatech.edu/~mleach/.../tcir/tcir.pdf

Cones that break up under any amplifier power below clipping are poorly
designed whether in 1951 or 2021. Why even suggest otherwise?

Cones break up *way* below clipping power. Just look at typical HF
performance.

Cone break up is a linear process. It happens at all power levels.

CAD is a method, not a design. Computers model where previously actual
experiments had to take place.

And so fast that many possible iterations can be tried where previously it
was totally impractical. It *has* revolutionised design in every single
branch of engineering.

Now, cutting directly to the chase... if an amplifier will produce a
flat response at say.... 60 watts/rms from say.... 5hz - 50khz, at less
than say.... 0.25THD, with a S/N ratio of 90dB-or-better, it is a
pretty good design... maybe??

It's pretty dated. Modern PA amps do far better.

0.25% THD hardly qualifies as a pretty good design these days. It's hard
for
a competent designer to exceed 0.025% today even when cutting costs.

Agreed. Then there is the matter of costs. Amps like the Berhinger A500 at
under $200 provide clean power and tremendous value.