Tubes, tubes, tubes—how we love to bask in their glow, roll them, and take their second-order harmonic distortion into our hearts as if it were a child or a pet. Some may put out so much heat that we have no choice but to open a window, turn on the air conditioning, or listen in the garb of Adam and Eve before that fatal first bite. As they and you age, you can never be sure who’s at their best. Tubes, at least, can be replaced, albeit at significant expense.
The special sound of tubes, which flows like water and sometimes shines like the golden sun you hopefully shielded your eyes from during the recent eclipse, makes it all worth it—if the design and implementation are good and you can’t get similar sound from low-maintenance solid state.1
I haven’t reviewed much tube gear, but when I have—Bruce Moore and VTL (in my pre-Stereophile days), Audio Research, and in our September 2022 issue,2 the towering Octave Jubilee Mono SE tubed pentode push-pull monoblocks3—I’ve been enamored of their sound. I waxed ecstatic about the “captivating beauty” and “heavenly” highs of the Jubilee Mono SEs. I can still recall how gorgeous they sounded; every listen was special.
Hence, my enthusiastic “yes” to a solicitation from John Quick, VP of Sales & Marketing for Dynaudio North America, Octave’s North American distributor, to review the smaller MRE 220 SE4 mono push-pull tube amplifiers ($28,500/pair base price, $37,100/pair in the ultimate configuration, which I received). Having discovered that the common output power specifications do not correlate perfectly with an amp’s ability to control bass, I reckoned their rated output of 200W average and 220W peak power into 4 ohms would work just fine with my reference Wilson Alexia Vs.
Options, we have options
Each MRE 220 SE monoblock uses four power output tubes—KT88s, KT120s, or KT150s are recommended and available from Octave—and three driver tubes: one 6SN7GTB (a 6SN7 with a maximum plate voltage that’s 50% higher) and two ECC802s.5 A few options are offered with the MRE 220 SE that can affect its sound.
POWER TUBES. You can choose among KT88 (supplied with the base unit), KT120 (adds $800/set), or KT150 (adds $1600/set). During an extended Zoom interview with Quick and Octave founder/chief designer Andreas Hofmann, Hofmann said, “To my ears, KT88 sounds quite a little bit soft. Sound and quality-wise, KT150 is best. But it’s also a question of the speaker and the quality of the system. If somebody has a less-demanding system than yours, the top is sharp, or the sound is darker, they may prefer KT88.”
You can boost the capacity of the (adds $7000/pair). The Super Black Box connects to the amp via a flexible, screw-on umbilical cord. Adding the SBB to the MRE takes only a few minutes.
