[sdiy] favorite "magical" opamp?

[David G. Dixon]

> On 6 October 2010 16:20, Tim Ressel <madhun2001 at yahoo.com> wrote:
> > Can anyone tell me the difference between the TL0XX series and the
> TL08XX? I
> > just looked at the datasheets and I don't see enough delta to warrant
> two
> > devices. What am I missing?
> 
> Typical input bias currents are the most marked difference I can see -
> TL08x is half that of the TL07x.
> 
> Not official but I've generally used TL07x for audio path and TL08x for CV
> path.

TL07x comes in three different grades relating to maximum input offset
voltages of 3, 6 or 10 mV.  Typical ratings are 2, 3, and 3 mV,
respectively.  I just bought 100 TI TL074BCN (low offset grade) from Digikey
and paid about $0.75 each (about $0.19 per opamp) for them.
STMicroelectronics makes a lower offset, lower bias version for more than
twice the price, but for that price I'd rather go for a better opamp (such
as TLE2074).  For the lower grade TL074CN, 100 sell for about $0.41 each, or
about $0.10 per opamp.  That's less than a garden variety transistor!