Krell Full Power Balanced 600 power amplifier System
When installing an amplifier of this power, due consideration must be paid to its line supply. Ideally, this should be a dedicated high-current line from the circuit-breaker box. Attention to such detail really matters here.
Throughout the review period, the FPB 600 continued to stretch my ability to take its full measure. In the main, listening was undertaken with Wilson Audio WITTs and WATT/Puppy 5.1s, in order of preference, allied to Quad ESL-63s. For vinyl playback I used a Linn LP12/Lingo/Naim ARO with both a Clearaudio Insider and van den Hul Grasshopper IV GLA, sitting on a Mana Four Stage platform. This was complemented by a Wilson Benesch turntable, ACT 2 tonearm, and Carbon cartridge. Head amplification was primarily handled by a Conrad-Johnson Premier 15. Digital sources included the Krell KPS-20i/l used as a transport, as a player, and, via its direct-coupled level control, as a complete source. Ancillary digital replay included the Cary 300 and the Audio Synthesis DAX-2, the latter with HDCD.
Line control, when separated from the KPS-20i/l, comprised a C-J Premier Fourteen (see WP's review in the December '96 Stereophile), the Audio Research LS15 (balanced and normal), and the Audio Synthesis Passion (passive, balanced, and normal)—plus a fixed-level, in-line Vishay attenuator, for test only. I also enjoy the modest luxury of three high-current (60A) AC lines connected to a 150A mains supply panel.
Line and speaker cables included the finest available from Siltech Silver, van den Hul Revelation and The Third (pure carbon), and Transparents too numerous to mention. Accessories included Tiptoes (conical spikes), Shakti Stones, Harmonix feet, and several Mana Acoustics equipment tables.
Power amplifiers for immediate comparison or of very recent experience, fully referenced to those used for the test, included the Mark Levinson No.333, Krell KAS-2, and Audio Research's VT150SE and Reference 600. My longer-term reference FPB 300 put up a good, fight aided by the ARC VT100, Conrad-Johnson's Premier Twelve A and Premier Eight A, plus Musical Fidelity's F19 power amplifiers. Stereo SE tube references included the UK's 211-tube-equipped Gamma Rhythm. It was a challenge keeping all this lot preheated and ready to joust with the FPB 600.
Driven to still greater extremes of analysis for sheer quality of bass extension, dynamic range, and stereo staging, I also took the FPB 600 to the nearest accessible pair of Wilson X-1/Grand SLAMM speakers—at UK importer Ricardo Franassovici's listening station at Wimbledon. After all that, I felt that honor had been satisfied!—Martin Colloms