5. Re: Olympus LS-14 initial thoughts

["Raimund" animalsounds]

> Thank goodness someone else understands what I have been rembling on
> about. :-)
>
> > For the INA163 this is 1500 - 2500 ohms, depending on what value you
> > pick for Ein (it is frequency dependent). This is certainly not 150
> > ohms, so I wonder what the actual real-world noise performance of
> > this op amp will be.
>
> My guess is 10dB improvement with a matching transformer, as we are
> discussing noise energies. In addition, two input amps to give a fully
> balanced input adds an extra 3dB noise. A transformer loses about 1dB.

David,

I already tried to explain that there will be an EIN improvement by 3 dB co=
mpared to a single opamp design. I still haven't found a transformer-balanc=
ed preamp having an EIN specification better than -130 dBu(A). Can you prov=
ide a reference on such a device? I'm afraid you cannot ;-)

Regards,
Raimund