If the specs for the DR-05 are accurate, I wouldn't add more than 6-8db of gain from an external preamp with this recorder if you're recording PA amplified music, better yet, add no gain at all.
With the overload of the DR-05 and typical condenser mics, if you add 6-8db of gain with a preamp, that should allow you to record up to about 118db SPL's before you overload the DR-05 inputs. 118db sound levels are certainly high, esp with A-weighting, but unweighted sound pressures of 118db particularly with pumping low frequencies from subwoofers at a show really isn't too hard to hit.
Which is what I was getting at with the LB, esp with tranfo's engaged. With the input tranfo's the LB has a minimum gain of 18db, without them, the minimum gain is 6db. It would really be best to run the LB at the minimum gain to avoid any overload distortion on the DR05. A little easier with the Church 9100, since iirc it is 20db max gain, and I think the gain goes down to 0db at the minimum.
