So - I see all of these pretty Dangerous, Tube-Tech, and SSL type analog summing boxes out there - but they are a bit expensive for a simple resistive summing network if you already own a descent make-up gain-stage IMNSHO.  Does anyone make a bone-simple PASSIVE DB25 (8 Ch) adaptor cable that would use simple resistors and sum the 8 channels to a pair of XLR's (which would pass into a Preamp for makeup gain)?

If not - is there an easy way to make such a passive summing cable with a DB25, some 1% 1/4Watt resistors, two XLR's and a Mic Preamp?  I don't need any type of Mono capabilities or fancy trim controls - just 1+3+5+7 summed to L XLR at a fixed level, and 2+4+6+8 summed to R XLR at a fixed level.  What about making one for 16 channels (2x DB25's) for two ADI8's as well?

Specific wiring and resistor values that would be appropriate for use with an ADI8 (or two ADI-8's for 16 Channels) and feed a Mic Pre with a Line Level Input would be fantastic!  I'm anxious to enter the world of analog summing.  I have an ADL600 preamp on the way and it should be a perfect make-up gain stage for this task (among other options at my disposal) :-)

Thaks for any constructive input on this low-budget summing solution.