Tube Power Amp Reviews

Though a selection of preamplifiers was on hand, the Defy-7's unusually high input impedance particularly suited it to two models: the tubed Jadis JPL (favorably reviewed by DO last January) and a passive controller, the admirable new Audio Synthesis Passion. The Audio Research LS2 helped deliver the maximum information from the Defy-7 and was ultimately preferred to the JPL on this basis. The latter was certainly highly sympathetic to the power amplifier's character but did not allow it to "breathe" fully; nor was the bass so impressive. In addition, the full measure of transparency possible from the Defy was not conveyed.

Helping to keep my reference standards in line was an Audio Research D400, a Krell KSA-150B and MDA-300, a pair of Meridian 605 monoblocks, and recent experience with a pair of ARC Classic 120s.

Digital sources included the Vimak 1800 D/A, with the Accuphase DP70-V used as a transport and a complete player. The Theta Generation III also performed sterling service. For analog disc, I used Conrad-Johnson PF1 and Krell KRC preamplifiers in conjunction with my trusty Linn LP12 Lingo/Naim Aro/Koetsu Rosewood II supported on a two-tier Mana table.

Cables were Siltech silver and van den Hul (The First interconnect and the Revelation hybrid speaker cable). The Wilson WATT 3/Puppy 2 was the main speaker system used for the listening tests; the sound quality produced by the combination of vdH carbon cable, Jadis, and WATTs often reached the sublime. Notwithstanding this extraordinary synergy, the Defy-7 was also used to consistently good effect with Quad ESL-63s, a pair of KEF R105/3s, and my own custom Celestion SL700s. The only drawback to these trials was having to carry this heavy amplifier upstairs to the second listening room!—Martin Colloms