Tube Preamp Reviews

Sidebar 2: JA's System

The Super-PAS 3 was given a degree of environmental isolation by sitting it upon four Audioquest Sorbothane feet (which also damp vibrations in the chassis, due to their large contact area), and was auditioned in the following system: A pair of VTL 100W tube monoblocks was used to drive Celestion SL700s sitting on their dedicated stands. Source components consisted of a 1985-vintage Meridian MCD Pro CD player, as well as a modified Magnavox '471 from Precision Audio, and a 1987 Linn Sondek/Ittok combination sitting on a Sound Organization table.

Not having an appropriate MM cartridge at hand during the review period, I had to resort to using the HFN/RR "Black Head" transformer, designed by Tim de Paravicini, to render the output level of my preferred Linn Troika cartridge compatible with the Super-PAS MM input. When specifying the design of what Ken Kessler and I came affectionately to call the "Zit" (footnote 1), I decided that it should only have a moderate voltage gain, to avoid overload problems in the following preamp circuit. Nevertheless, the Troika used straight into the Super-PAS gave a noticeable improvement in transparency compared with the step-up, but critical listeners would have felt the background noise level to be too high. Its character, however, was surprisingly innocuous, being a soft rushing noise, pleasantly pink rather than white, with a complete lack of hum.

In addition, I carried out bypass tests on the phono stage by auditioning CDs and some of my own 15ips master tapes, the latter played back on a 1975 vintage Revox A77, via an inverse-RIAA network into the Super-PAS's phono inputs. Interconnect was Monster M1000, with two runs of Monster M1 speaker cable used to bi-wire the Celestions.—John Atkinson

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Footnote 1: Was this ever a case a giving a dog a bad name! It was finished in black and was a less expensive, less versatile version of Tim's fabulous "The Head" transformer; the nomenclature seemed so appropriate.