[sdiy] op amp substitutes

[harrybissell]

I agree with almost everything you said...

(but :^)

The 4558 is not THAT bad of an opamp.  Even the 741 has its uses. Why do you
think that they have not been replaced and are still around.

The 741 is extremely rugged. It is NOT fast, that is a virtue in some cases. In
a lot
of circuits if you use a FASTER opamp it will become unstable.

I once tried to replace the 4558 in the 360 Systems "Slavedriver" thinking
1) it was a brother of the 1458 (not - it is MUCH better)
2) I could EASILY find a superior replacement.

I was wrong. I could not easily find a lower noise opamp.  The 5532 comes close
with lower noise, much higher current, and pretty bad offset voltage problems...

The LM324 is a different animal.  While for SH!T in audio, it is very useful in
single
supply applications.  I even use and stock them... and they are on my BBD list
:^P

H^) harry

anthony wrote:

> Ken Stone wrote:
> >>
> >>This is in the Analog Shift Register circuit.
> >
> > In my analog shift register circuit?  Use 3140 instead of the LF356 for
> > best
> > effect. I wouldn't waste my time trying a TL0X4.
> >
>
> Oh yeah. Yes indeed. The 3140 is another op amp I tried to find a
> replacement for in my pile o' stuff but alas to no avail. I could tell right
> away as I read the 3140's data sheet. They're on my shopping list. I thought
> the TL03X and TL05X might be significant improvements over their
> predecessors as replacements for the 356's.
>
> I knew the C4072's were no good for capacitative loads. .
>
> I thought it might be interesting research to see what op amps might replace
> others in a number of situations. And how this might relate to specs in a
> datasheet and how that ends up translating into real world apps.
>
> Example: I have a huge batch of NJM4558's (JRC) of early 80's vintage (from
> the equipment they were in, the dating is probably fairly accurate depending
> on how long they sat and waited to be put into something) which is
> technically a pretty crappy op amp. Better than a few but not many. But in
> some of the audiophile nut circles (the ones who like op amps) this
> particular make and this particular vintage is choice (I have not tested
> this though. I'll try one against a 5532 some time. the 4072's might be good
> for audio audio.). But for anything other than audio - probably nice for
> filters -  I'd probably only use them where they called for an 358 or a 1458
> or a couple in place of a 324 (but I have a ton of those too - more than
> 1458 and 741's combined).
>
> I think there's a lot of the same types of "euphonic shortcomings" in some
> op amps like with tube amps.They're different shotcomings, but to some
> people they sound good But tubes sound cool mostly by virtue of simply being
> tubes. Op amps only in special cases by being quirky or really just a damn
> good op amp. I have tinnitis really bad so I like hiss a lot. (I love pink
> noise. I can't stand noise from a pseudorandom generator though.) As in
> calling for a 741 because it has a slow slew (slow slew slow slew...) rate.
> But I digress...
>
> I have fun trying to switch plans around so I can use the crap that I
> already have, but I realise that there's a point of diminishing returns. And
> then I have some things that I think are really really cool, but may not
> actually be as great as I think. Like the Rubycon oil caps that I have. For
> a while I just had them in with my non-polarized electrolytics, but then one
> day I thought 'hey those aren't electrolytics.'  I can't for the life of me
> remember what they were in but there were a lot of them in there.
> Digressing again...
>
> But I haven't tried a 386 or a 380 in place of an op amp yet. I'm pretty
> sure that won't work for the buffers in Ken's ASR though. But maybe I'll
> play with it anyway. I have so many IC amps, I'm curious what some of them
> might do in place of an op amp. I'll wager someone has already tried it.
> I'll bet if there's a good reason on paper why they won't work very well in
> most apps real world experience might
>
> And I found a cool use for just a single 3900 (which is all I've got) on
> Ken's site - the Analogic.