Speaker Matching
Historically, negative feedback in single ended pentode amplifiers was quite common (for example, the Mullard 3-3 design built around EL84). Today negative feedback is less popular with SET amplifiers, with many having no overall feedback loop. Their frequency response, limited by transformer passband, is then modulated by irregularities in loudspeaker impedance. This, and the very low attainable power levels (3 Watts for 2A3 to 20 Watts for 6C33C), requires careful matching of amplifier to speakers; selection is usually limited to high-efficiency loudspeakers with a sensitivity exceeding 90 dB/Watt.
Read more about this topic: Single-ended Triode
Famous quotes containing the word speaker:
“If the oarsmen of a fast-moving ship suddenly cease to row, the suspension of the driving force of the oars doesn’t prevent the vessel from continuing to move on its course. And with a speech it is much the same. After he has finished reciting the document, the speaker will still be able to maintain the same tone without a break, borrowing its momentum and impulse from the passage he has just read out.”
—Marcus Tullius Cicero (106–43 B.C)