roland 4558 op amp data.

[harry]

Hi Richard...

This could be a long topic... answer is
"not always"

Different chips have different characteristics... The slew rate of the 4558
and 1458 is quite slow compared to the TL072.  Maybe the faster chip
will improve performance, maybe it will oscillate !!!

The input impedance of the TL072 is very high... maybe this is good maybe
not...

The 1458 / 4558 chips have very good current limit circuits.. they are much
harder to kill than a TL072.

The 1458 / 4558 can be driven into clipping without the dreaded "phase
reversal"
the TL072 is not polite in this case.... (see input common mode range...)
Some data sheets will not TELL you that their chip will phase reverse !!!

Sometimes designers use a chip because it is the cheapest one available that
will
do the job... or the best one.  Use an IC socket  (I like AMP Diplomate) and
then
plug in your replacement and give it a try !!!

H^)  harry

I find that designers who have gone before me were either idiots or far more
clever
than I can perceive.  I assume they were smarter than me until proven
otherwise !

Richard Ford wrote:

> In message <3A611BDC.1343E6FC at prodigy.net>, harry
> <harrybissell at prodigy.net> writes
> >except for noise spec guarantee, the 1458 (dual 741) is a replacement !
> >H^) harry
>
> Surely a TLo72 would be better. Very low noise at a low price.
> --
> Richard Ford