From:    Geoff 

> Date:    Sun, 23 Dec 2012 20:15:55 +0000
>
> I have tried every op amp circuit I can imagine as a preamp.
>
> Yet I can not rid a small DC drift which is either related to
> ambient AC noise level or DC drift of resistance or
> thermocouple voltage related to the soldering of junctions.
>

The best geophone op-amp I have found is the ADA4528 but it is available
only in tiny surface mount packages that are difficult, but not impossible,
to hand solder.

http://www.analog.com/static/imported-files/data_sheets/ADA4528-1_4528-2.pdf

I solder them onto DIP8 carrier boards to use in my old DIP pcbs.  I could
send you
one on a DIP8 carrier board to try in your DIP socket if the pinouts are
compatible.

The ADA4528 has much better specs than your LTC1050, but you will still need
some type of high pass filter to get rid of drifts longer than about 30
seconds.

I am using a software highpass filter in my microprocessor firmware to get
rid
of these long term drifts.

Dave
From: =A0 =A0Geoff <gmvoeth@........
om>

Date: =A0 =A0Sun, 23 Dec 2012 20:15:55 +0000



I have tried every op amp circuit I can imagine as a preamp.



Yet I can not rid a small DC drift which is either related to

ambient AC noise level or DC drift of resistance or

thermocouple voltage related to the soldering of junctions.

The best geophone op-amp I have found is the=A0ADA4528=
 but it is available
only in tiny surface mount packages that are=
 difficult, but not impossible, to hand solder.


http://www.analog.com/static/imported-fil=
es/data_sheets/ADA4528-1_4528-2.pdf

I solder t=
hem onto DIP8 carrier boards to use in my old DIP pcbs. =A0I could send you=


one on a DIP8 carrier board to try in your DIP socket if the pinouts a=
re compatible.

The=A0ADA4528=A0has much better spe=
cs than your LTC1050, but you will still need
some type of high p=
ass filter to get rid of drifts longer than about 30 seconds.


I am using a software highpass filter in my microproces=
sor firmware to get rid
of these long term drifts.

=
Dave
=A0