OK, so I have received my ST-70 from Atmosphere, purchased new tubes as recommended by Ralph, biased the tubes, and hooked to a set of Clestion F15 speakers for a trial run. Amp works perfectly and sounds wonderful. Ralph was a treat to work with, had several conversations around his recommendations as what to do and pretty much followed his recommendation to a 'T'. Ended up keeping the amp as original as possible. I am very pleased with my choice to refurbish. Thanks Ralph! Thanks to all for their input toward this end! As I indicated on another thread, I am still looking for speakers that mate well with this amp.