You are looking for something like this. You don't list your preamp so not certain if it will feed lightpipe, or adat or what.
http://www.sweetwater.com/store/detail/FireStuLP/
I am sure there are other manufacturers making similiar products, A/D/A converters.

well the idea there is good but I need to plug the TRS outputs of my pres into the unit - not sure how the lightpipe idea works.

Wel that was why I was asking what preamp unit is it?
What unit is it?

If this anonymous preamp really is that good, you will need a FireWire 8-channel A-D interface with line-level inputs that are not attenuated and put through its own pre-amps.

The RME FireFace 800 will do exactly what you want. Other possible interfaces at markedly different points in the price-quality curve are the MOTU 828 and Lynx Aurora 8/FW.

hmmmm . . . .

well it certainly looks to be cheaper just to keep the 1220 and use it as an A/D/Firewire converter.

The Onynx pre-amps are among the best in their class, but have you considered carrying out the standard modification to the Oynx series that moves the recording/FireWire take-off point to after the insert (and EQ etc)?

[="http://www.graymattersound.com/onyx1640"]This[/]="http://www.graymatt…"]This[/] is the 1640 mod description, but it's similar for a 1220. [[url=http://="http://www.frontend…"]Front-end Audio[/]="http://www.frontend…"]Front-end Audio[/] offer to carry out the mod on the 1220.

With the modification in place, you would take an unbalanced output from your too-wonderful-to-mention-the-name-of pre-amp to the insert return on the 1220, thus by-passing the Onynx pres.

Boz wrote "too-wonderful-to-mention-the-name-of pre-amp"
Too early to have coffee coming from my nose, laughing so hard. Should be a brand of its own.