I need comments about "100W power amp. elektor april 1982"

[bvp9223]

Hope this will help.

BvP

[jacco vermeulen]

Guido , howcome you did not build the Elektor Mosfet amp later that year.
I was told that it was often used for PA purposes.

Also thinking of adding a thread here for Brabo's !

[jinkuchi]

That's picture is right! That's it.
But he changed something.
He change the output darlingtons with MJ11016 and MJ11015.
1 What do you thing about this modifying?

2 What circuit you suggest me to do? I want to build better transistor amplifier than this amp.

[destroyer X]

I feel happy to see so good work, with so common components, pretty image.

Congratulations!

regards,

Carlos

[jmateus]

There was some confusion regarding this (or the other) amplifier.,

It turns out there are TWO diferent amplifiers published in 1982 by
Elektor, one is this with darlington outputs originally BDX66 and 67,
the later published latter in December 1982 and baptized as the
Crescendo with MOSFETS outputs...

In January 1983 Elektor published Accessories for the Crescendo
a circuit for power up delay, protection and so on... In November 1983 there was an article with Modifications called Crescendo revisited with a very small modification to prevent oscillation.
In May, 1984 Elektor published another version of the Crescendo
this one smaller, with less power, which I built too....I guess I
was a big fan of the Crescendo at the time....But I'm cured now!

I built both, the Crescendo first and still working after all these years,
however it wasn't the amplifier of my choice, the quality wasn't
that good but still occupies a big cabinet stached under a small
desk. What is it doing there? Nothing, taking space.....

However, a few years latter I built the one with darllington outputs
which doesn't have a name, probably because doesn't have parents
(é filho da p....), but in fact it is a much better sounding amplifier even
though it ended up again in a box full of junk.... A couple of months
ago, due to the fact that I had a different design (only aestheticallly
which made me not to recognize the amp), I built the SAME amplifier
and spoke to Carlos about it asking him to do an evaluation to the guy...
About that Carlos and I had a little quarrel because (again) I did not
recognize the amplifier on the simulator as the simulator didn't have
any darlingtons in its data base....

Well, to made story short I built the amplifier AGAIN and for that
I did another layout which was completely different from the first
one (how could I recognize the beast from the other animal?).
I did not change any value of components except the small input
cap for radio freq., and the amplifier is perfectly stable and easy
to adjust, supplies the power for which it was designed (around
50Watts) and finnaly is very pleasant to listen to. Nothing of that
Hi End nature, but very pleasant...

And this the history of the atribulated and already famous Elektor
amplifier...Do you guys want to know something? Even though
it doesn't have a reputation of certain amplifiers that everybody
is talking about as being this or that, not to speak about the ASKS
more elaborate ..or less definitions, this amplifier is definitelly a
WINNER. End of story......

[jacco vermeulen]

Thank you for the clear-up Mr Mateus.

Again i learned a lesson, at the time i had both designs, i built the Crescendo as i regarded it as the more sophisticated amplifier in '82.
I suppose schematics are good for building, judging should be for the ears.

[guido]

Originally posted by jacco vermeulen
Guido , howcome you did not build the Elektor Mosfet amp later that year.
I was told that it was often used for PA purposes.

Also thinking of adding a thread here for Brabo's !

Think it was recommended back then as something i could manage. It was my second amp (the first never got to a working stage ) Too long ago,

mvg,

[jinkuchi]

thank you jmateus.

now I want to built ESP project 3A.
But I can't buy MJL4302 mjl4281 in Thailand.
I found MJL21193 MJL21194, can I use them instead?

Can I use TIP3055 TIP2955 ?

[Nasse]

There was still one Crescendo update, Crescendo Millennium Edition in 4/2001, if i remembr the circuit was optimised for modern power mosfets or something

[jmateus]

I forgot to add that in March 1985 Elektor published another amplifier,
again with MOSFETS outputs (same ones obsolete now, $18.00 a pop)
called AXL amplifier, designed to work class A, B or AB, depending on
the power supply and bias...
At the time the 2SK134 and 2SJ 49 were $4.50 each.....

This is a very interesting design, different topology than the previsous
ones (crescendo and derivates), with the possibility of being constructed inexpensively mainly for electrostatic headphones, for
an active speaker system or a small hi-fi installation.

The input stage featured a dual symetric differential amplifier formed
by 4 cascode pairs... I haven't seen this kind of technique since that
publication, this is why is interesting to me....

This one I never built, but....I'm thinking, may be I'll build it now!