differential 1/s

[Martin Czech]

Reading the HUSH Circuit appl. notes (AD, SMM2000 
www.analog.com/products/sheets/SSM2000.html) I came across one sentence :

Lowpass filters (or integrators 1/s) have fixed dc gain, so
control feedthrough and dc level shift can cause problems.
(So they use a differential ota with a differential 1/s stage,
so errors will cancel.)

Very true, I already had to notice such severe offset effects that 
made it impossible to have a subaudio lowpassfilter for lag control
or random voltage control.
I thought  maybe a switched capacitor filter would be better in this 
case, but this causes other problems as propper scaling etc.

Now , Analog has meanwhile a vca with differential current outputs
(SSM2118T, just cut of the current to voltage converters of 2018T).

It would be possible to have a vca with differential current output,
feeding a "floating" cap differential 1/s stage thus having an improved
filter for audio and/or subaudio.

EEs out there : what do you think about this idea ?
What are the chances for achieving error cancelation ?

m.c.