Hi: Like you, I recently went from an SET to the Aronov LS-960i. I'm currently using JJ Blue Glass KT88s and Telefunken 12AX7s. A very significant improvement over the stock tubes. Sound is lively, up-front, detailed (without edginess) and with great bass slam and PRaT. (Doesn't have the midrange "magic" or holographic imaging on my old Unison 845s, though. But you can't have it all when you down-size. I guess.) The JJs were much better than the Sovtek KT88s I tried - the Sovteks seemed to be much thinner sounding and more microphonic to me. I've heard that KT90s also work well in the Aronov but I haven't tried them. Sure is nice to be able to just insert new driver tubes and not have to worry about re-biasing them. Let us know if you find other tube combos that work well.
BTW, I'm told the amp responds well to better power cords. A friend who had one used an Electraglide to very good effect and this brand was also highly recommended by the dealer I purchased the Aronov from, Stewart Marcantoni of Weekend Environments. He used to be the top Aronov retailer in North America and is very knowledgeable about Aronov products as well as an all-around good guy to deal with. Good luck
Flacre
BTW, I'm told the amp responds well to better power cords. A friend who had one used an Electraglide to very good effect and this brand was also highly recommended by the dealer I purchased the Aronov from, Stewart Marcantoni of Weekend Environments. He used to be the top Aronov retailer in North America and is very knowledgeable about Aronov products as well as an all-around good guy to deal with. Good luck
Flacre