[sdiy] op amp substitutes

[anthony]

----- Original Message ----- 

>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.


Oh I said it was 'technically crappy'. From me that translates to "The 
datasheet doesn't add up to what I've seen in real world applications. I 
took apart a Sony boom box and the preamp was it's own little unit. It used 
a 4558, I took of the worn out slider pots and it's good for a phono preamp. 
I even used the EQ on it for the RIAA thing. I was going to swap in a 5532, 
but I think I'll swap in a JRC version in place of the NEC one that's in 
there.

> 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 haven't run into many 741's oddly enough. Seems like most equipment uses a 
1458 or a 358 and especially 324's which is kind of weird. It could be 
possible that I simply overlooked the 741's and 1458's when I desoldered 
stuff.


I like it that sometimes a slow op amp is good.

> 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 thought the same thing! I found like 20-25 of them in with my 1458's when 
I did a little op amp inventory the other day.

> 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...

Good to know these pitfalls before hand I had planned to substitute 5532's 
for another one.

> 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

An old electronic drum, the DR7 and also the DR8 used 324's all over the 
place.