I don't get the fortune in maintenance for the SP-11 MkII. I recently had mine completely serviced by ARC authorized tech (High End Audio Repair in Brooklyn) and it was very reasonable even if I did supply the NOS tubes (Telefunken CCA for phono and the rest Mullards). I did not know that they had become so expensive, though. Unless you upgrade so frequently that you don't keep a piece for long, maintenance is required for any gear (except my Kenwood tuner :-).
Audio Research Preamp Experts?
Aside the from the notion that the latest is the greatest, which 3-4 ARC preamps from the past would be among ARCs best linestages? From the 3A forward. I don't care about phono performance, though I will consider the preamp even if it has phono built into it. Any sleepers from the past to compete with today's linestages?