Doepfer

Dieter has already mentioned the key fact which I omitted last night
(I wasn't sure just what your experience level was then), in that the 
TL082 converts the currents from the PA381s to the voltage which is 
then output. It is this current conversion that would require
separate op amps for each channel, and getting at the individual 
currents is the hard part. I can think of 3 ways to do this, easiest 
first:

1) Cut the tracks from both sets of pins 1 and 7 at some convenient 
point, and then add wires from the pins to the new op amps

2) (Really depends on your soldering skills): remove the PA381s
from their sockets, desolder the sockets, then bend pins 1 and 7 on
the sockets out so that they don't go through the PCB, and to which
new wires can be attached, then re-solder sockets into PCB
(advantages are that no tracks need to be cut, but it will be quite 
hard to make a tidy job of it!)

3) Remove the PA381s and bend out pins 1 and 7 on _them_ and
re-insert, again so that wires can be attached to the IC pins (given 
the cost and difficulty of getting replacement PA381s I personally 
would certainly *not* do this, but it is an option!)

If you a this point you are still interested, come back to me (perhaps 
off-list?)

> ok, i was trying to use the lf444 quad op amp,,,, and i couldn't get a
> single thing to happen other than some crummy low end noise.
> 
> perhaps i'm not biasing something correctly,,,

The op amp summing the currents holds the summing point at ground 
potential, so the voltage at the output from all the PA381 amps is 0V, 
which is why you got nothing. (This is in fact a necessary condition 
for running the PA381 - it uses the voltage at pin 7 as a reference 
voltage.)

> i didn't implement any caps inline with the lf444, i was simply
> following the basic circuit listed on the pa381 data sheet.....

Which is basically all the TL082 is/does, apart from the feedback 
resistor value (and the cap).

> yes, more help is greatly appreciated, especially if you could show me
> how to do this using the lf444 chip instead.

I can't see any reason why this wouldn't work as well as, say, a
TL084 - but since it is not a simple matter of picking off some
voltages, it all comes down to whether you want to go ahead at all!

Tim