I thought this was a little interesting. It is not super low level DIY gear and may possibly not be DIY but in a Musician's Friend video on Michael Wagener a couple of the screen shots clearly shows Seventh Circle Audio's rack of preamps.
http://www.musiciansfriend.com/mediacenter?ch=hc&cat=Interviews&vid=MichaelWagener_Studio_part2&playlist=interviews&audienceId=16817579&tiid=1355&src=3NL0EK1&ZYXSEM=0
CC
http://www.musiciansfriend.com/mediacenter?ch=hc&cat=Interviews&vid=MichaelWagener_Studio_part2&playlist=interviews&audienceId=16817579&tiid=1355&src=3NL0EK1&ZYXSEM=0
CC