Sonic Frontiers with Digital Tone Control...?

I have a Sonic Frontiers Line 1 in my system, and for the most part I really like it. For some of my recordings, the older stuff - like late 50's jazz - or anything poorly mixed, I've been thinking of how nice it would be to have some clean (i.e. digital) tone control. I'm thinking of buying an NAD 118 as a secondary preamp. For most of my use I'd just run the SFL1 simple and clean. For other recordings, I'm thinking of putting the NAD118 into the system, for tone/separation/compression control.

Here's my question. How can I hook this up so I don't have to switch cables in order to use the NAD: through the tape loops ins and outs? through the SSP input (in which case I'd need some way to get a source signal into the NAD)? Some other way? Help me out fellow audiophiles!

FYI, my system is as follows:
* Martin Logan ReQuests
* Sonic Frontiers Line 1
* Sunfire Two Channel Amp
* Rotel 971 CD playerr

Thanks in advance
It should go thru the SSP input since the tape loop is a fixed gain that would probably blow up your speakers. You would have no volume control thru the tape loop. You would have to run a seperate output from your phono into the NAD as well as the SF. You could try a 1 to 2 adaptor and see if it interferes with your sound quality. If it does you would simply run the phono into the preamp that you are using at the time. Your other option would be to use an equalizer into the SF. Since this is basically only for older records with sonic issues it would probably work great. The EQ would run thru the tape loop of the SF.
Your pre amp is already a tone control, it has tubes! Purchase a Mullard tube for a warm rich sound, an other type for a more open sound etc. This can really make a difference