Trying to add a Main-in/Pre-out to a Sony amplifier:

(There were useful replies, in an earlier thread, from K. Robinson,
Jerry G. and NSM about this topic)

The amplifier model: Sony TA-F590ES, with motorized volume control.

The amplifier has an "adaptor loop" with bridged IN & OUT cinch(RCA)
connectors before the volume control.

The aim is to insert a 2-way active crossover, and resend the
high-range output to the Sony. The adaptor loop won't do since it come
before the volume control.

One point worth mentioning: the "Pre-out" and "Main-in" under
discussion need not have "universal" characteristics, since they will
*only* be dealing with an active crossover (and perhaps an equalizer.)

It has been suggested by NSM: "post a circuit diagram and several of
us could tell you where to add them"

Here are the block ad circuit diagrams:
http://nom.de.plume.free.fr/temp_files/
The diagrams are for the TA-F590ES and a variant, the TA-F690ES.
The latter has a Pre-out, but no Main-in.
We are discussing here the TA-F590ES

(Please consider that the content of the files may be copyrighted.)

Thank you, in advance, for your contributions.