"Marte Schwarz" wrote in -
berlin.de:

Hi,

I'm considering an op-amp for making a DC coupling adapter to a soundcard
to
convert it to signal logging purposes while retaining its audio
performance.
It uses a passive adder and a gain of 2 to add a bias voltage to the
signal
before an ADC input.

The sound card is one with external analog circuitry in a rack unit, it
has
20 bit signal conversion, so this op-amp will have to be good to maintain
that and the other specs this unit has.

So did you think about noise?


Yes, several times. This amp has THD+N of 0.00005% and is going into a device
specificied as 0.002%. Good enough? I think so.

As all the other figures for dynamic range and noise are so good that they
will allow the original specs for the entire unit to remain intact,

are you shure? What's about your supply?


I described that already, with regard to slew rate and maximum possible
voltage change in a given time at maximum sample rate, so yes, I think I
considered that too.