Audio Research Reference 6 Preamplifier

In late 1972, Audio Research Corporation released what would become one of ARC’s bestselling preamplifiers of all time: the SP-3. While available, the SP-3 earned praise for its low noise levels, wide soundstages, and awe-inspiring transparency. More than one audio publication described its overall sound character as “a straight wire with gain.” ARC sold thousands of SP-3s at $595 USD before discontinuing the model in 1976, but what I find interesting is how much of the SP-3 remains evident in more recent ARC models. By today’s standards, the SP-3’s faceplate of brushed bronze over satin black, rotary analog controls, and big pushbuttons look dated, but the three-box segregation of the faceplate and orientation of controls aren’t all that different from those of ARC’s SP-20 preamplifier ($9000, recently discontinued). Then there was the SP-3’s tube complement: six 12AX7s in the analog stage with two 12AX7s in the tone control circuit. This arrangement in the analog stage, albeit with different tubes, can be found under the hood of the subject of this review: ARC’s Reference 6 preamplifier.