November 12, 2012
Today’s installment covers the Genalex KT88 output tube. The reader is directed to my original posting on these tubes, when used in my Premier 11A, for information regarding their physical construction and initial listening impressions.
The Genalex KT88s in this review were used in the Premier 140 power amplifier which passed the 1,000 hour mark, since its upgrade, during their audition. At this point in time, the CJD capacitors that were installed in the 140 should be fully broken-in. Other tubes used in conjunction with the review set were Telefunken PCC88s in the Premier 16LS2 preamp and as the input tube for the 140 (I now have a complete set of seven) plus the Sovtek 6H30π-DR phase splitters, also in the Premier 140.
The review set were comprised of one quad of Genalex Gold Monarchs and a quad of Genalex KT88s. The tubes are essentially identical with the only difference being that the Gold Monarchs were intended for sale in the United States while the latter were marketed elsewhere.
The Genalex KT88s replaced the SED 6550C power tubes and my comments below are relative to their differences.
- The increased power capability (42 watts dissipation for the KT88 versus 35 watts for the 6550C) is immediately apparent with a louder presentation at equal volume settings and a more powerful bass response with greater overall dynamics. As a result, the music has a more solid foundation.
- Slapped percussion is more realistic although with less transient snap. Transients are detailed but not as sharp as with the SED 6550C.
- Midrange is harmonically richer and voices are more chesty.
- There is less sparkle in the mid- to upper-treble. However, chimes, church bells and the like are extremely realistic and reminiscent of the GE 6550A in this regard.
- The sound stage is populated with denser images that are well-layered.
I continue to be very impressed with the Genalex KT88 and these are most definitely a top tier power tube. Although extremely expensive in today’s market, they reward the listener with a presentation that is natural and always at the service of the music. The changes in the resolution of the Premier 140, especially with its fully formed caps, highlight this tube’s capabilities.