roland 4558 op amp data.

[tomg]

The 4558 almost always has a "sound" of it's own when used in the 
design something.....and even then you can take a pile and find
differences between suppliers. Luckily the NJM4558D ($0.22) 
from Mouser is one of the best "sounding" of all. It's really good for
a certain fuzz box...;-)

Tom



> 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
>