Aguilar DB659 Preamp. In very fine shape, and loaded with NOS RCA 6881 spiral filament tubes. These are the mil-spec rough duty 12ax7 subs, and are very sweet, and over drive later rather than sooner, and do it nicely when they get there. The DB 659 is able to cop a great range of tones thru it's deceptively simple eq layout, and deep and bright switches. Details and specs can be found in the factory manual here: http://www.aguilaramp.com/pdf/support_manuals_db659.pdf $475 + shipping; or: might consider trading for an Eden Navigator WP100, or Little Mark LMII, F1... thanks!