Lewm
Yes, it was a dilemma that took a while to resolve. I use active crossover and pass the signal below 80 Hz to a separate pair of subwoofers with SS amplifiers mediated by a tube rectified preamp. The ribbons themselves are motivated by four channels of 50 watt Wavac SET amplifiers MD 572. The small foil supertweeter array is very efficient and is over powered with a 7 watt single ended el 84 amplifier. With the efficiency savings from the active crossover, i estimate the effect is about equivalent to 200 watt per channel SET driving the ribbons. SET's do not have problems with moderately low impednce, they are much more stressed by COMPLEX impedances, they see ribbons as static resistors.
Yes, it was a dilemma that took a while to resolve. I use active crossover and pass the signal below 80 Hz to a separate pair of subwoofers with SS amplifiers mediated by a tube rectified preamp. The ribbons themselves are motivated by four channels of 50 watt Wavac SET amplifiers MD 572. The small foil supertweeter array is very efficient and is over powered with a 7 watt single ended el 84 amplifier. With the efficiency savings from the active crossover, i estimate the effect is about equivalent to 200 watt per channel SET driving the ribbons. SET's do not have problems with moderately low impednce, they are much more stressed by COMPLEX impedances, they see ribbons as static resistors.