We thought Audio Research's previous-model SP-2C (footnote 1) was excellent, but this is even better—the closest thing available, in fact, to the ideal straight wire with gain. Our sample had a minor glitch—there was a slight "plop" if you rotated the tone controls rapidly—but we could find nothing else about it to criticize. Currently, by far the best preamplifier than money can buy. And would you believe it uses tubes (at reduced heater voltage, for extended life and cooler operation)!