> I've spent some time with the INA163 data sheet, and it is basically
> very good. However, the EIN figures at low gain are poor due to a high
> output stage noise level, and the quote appears to be at 60dB gain
> setting which is high for general field recording. A studio mixer
> could easily have the gain resistor on a preset, but it can't be
> easily incorporated into a fader in a portable mixer. Switched
> preset perhaps.
>
> What may be a problem for battery use is the twin rail power supply.
> The minimum rail to rail voltage is 9V - the end point of a 12V
> battery. At 10ma current per stereo stage, the battery requirement for
> a standby device is getting a bit high. I may have a play with one -
> with a transformer. :-)
David,
I have built a simple preamp with variable gain using the INA163 and I meas=
ured an EIN of -130 dBu(A) at high gain settings!
If you was not satisfied with the higher noise floor at lower gain settings=
(which should not be an issue in nature recording at all), then you could =
build such an instrumentation amplifier using discrete components, which wo=
uld allow you to further optimize the design. I think this is what SoundDev=
ices does in their current line of products.
Raimund
|