[sdiy] The sound of various Op-Amps

[harrybissell]

Arrrhh now you put me over the barrel :^P

The way I remember it (I am not Einstein :^) is that in order
for the low noise of the 5532 to really be a feature, you need to
have resistors small enough so the noise of the resistors themselves
do not dominate the input stage noise.

With low value resistors, you get the benefit of the reduced noise...
at higher values the benefit diminishes.  If you can stand the input
current (ie low input impedance) the 5532 wins. If you need the really
high input impedance, the TL07x series wins.

Again... not my own work here (and I forgot the reference....)

H^) harry

Andre Majorel wrote:

> On 2003-09-21 20:58 -0400, harrybissell wrote:
>
> > The 5532 is best suited for really low input impedance... maybe 1K would
> > be optimal and 10K an outside limit.  Higher than that...all your low-noise
> > benefits fade away.
> >
> > It also has pretty poor offset voltage, which means in high gain
> > applications
> > you better use it as an AC amplifier only.  I tried a DC coupled amp ONCE
> > and found that once I reached the gain I wanted... the output offset was in
> > VOLTS.
>
> Thanks Harry, that's interesting. I understand the DC offset stuff
> but what makes you say it's only good for low input impedance ? Is
> it the high biasing current ? (500 nA for the 5532 vs. 65 pA for
> the TL072)
>
> --
> André Majorel <amajorel at teaser.fr>
> http://www.teaser.fr/~amajorel/