It's been a long time since we've seen a really new tweeter design. Only five basic types have ever been developed: cones, domes, panels, ribbons, and ionic plasmas. And the most recent of thesethe long-defunct DuKane "blue-glow" Ionovacwas introduced 40 years ago. Since then, tweeter development has been more evolutionary than revolutionary, a series of refinements that has made them more efficient, more reliable, and smoother and more extended in response.
Interestingly, Bob Carver chose vacuum tubes to realize his dream of building the ultimate power amplifier. The Silver Seven uses fourteen KT88 output tubes per channel, and puts out 375W into 8 ohms. Bob built three pairs of Silver Sevens, not expecting to sell many at the $17,500 asking price. When those sold quickly, another 10 pairs were manufactured. Now, demand is so great that Silver Sevens are built in groups of 30 pairs.
