As some of you may know, in the last few years I have migrated from Naim 552/500/DBLs to some custom built speakers and tube amps and have never looked back. A friend of mine who was running DBLs actively with 3x500 did the same and also loved the final results.
So, in an effort to complete his system he decided almost a couple years ago to consign a ne plus ultra phono stage, from the same source as all of our other electronics and speakers. Which was finalized in the last couple weeks having been the subject of many listening tests and slight (and not so slight) circuit revisions.
It is based around an 850VA transformer feeding a B+ voltage of almost 600V to a pair of NOS 6SN7s, each of which has both sides wired up. One critical features is the signal to the tubes is direct coupled...no DC bias to the grid and no coupling caps. Other salient points is the use of some amorphous core Lundahl step up transformers, Cardas caps and tant resistors in the RIAA (which tests linear to less than 0.1dB across the entire spectrum), no rumble filter and point to point wiring. The end product is probably the size of a NAP300 power supply and weighs almost as much (it has a wooded box instead of a metal chassis).
