AUDIO RESEARCH SP-10 MODIFICATIONS

@autospec: Good point about after-market mods done by those who don't fully understand the stock design, and the reasons the designer did what he did. Roger Modjeski of Music Reference regularly received in for repair amplifiers of his which had been butchered by someone replacing perfectly fine parts with inappropriate ones. Inappropriate in terms of those parts not performing in the manner the circuit in which they were installed required.

BDP24:   Very well put, Most people don't understand the intermingling of components,les they be good or bad , expensive or cheap..........I need a old school Audio Research technician like Chris from the old days, but Chris is gone to.............   

Does the manufacturer still service these? I had an SP-10mkii that went back and forth to ARC when WZJ was still around. We tried gel tube sockets to minimize microphony- didn't work; and the factory hot rodded it per something that HP discussed- I can't remember what was bypassed in the hot-rodded version. To me, this model was the height of the original tube preamp era for ARC. There have got to be schematics for the unit, no? And some restoration shops could follow those. I think Audio Classics (or whatever that used McI shop is called) restored a Marantz 7 for somebody on SH forums who bought a unit which suffered a gutted  phono stage that had been replaced with solid state circuitry; the shop restored the unit to original design.