For now I intend to use my custom 7591/6sn7, fixed-bias, push-pull amp which uses a Pilot 410 input and phase inverter circuit built on a stripped Heathkit AA100 chassis retaining the great transformers. With this venture into high-efficiency horn speakers, at some point I tempted to try a 2A3 or 300b triode amp. The ALK Engineering site though highlights the seriously flawed crossover impedance curves of vintage Klipsch designs and my sense is that would not make a mini-watt triode amp happy. Should I get serious, an investment in the brilliant, but not-so-inexpensive ALK crossovers would be the next step.