At <$1,000 I can also recommend the Wright Sound WLA12A. I previously owned a modded Dynaco PAS and a stock Bottlehead Foreplay I (both 12AX7) and they were just too warm in my system. The Wright leans way more toward the neutral side and the tube rectification gives it that last bit of smoothness compared to the AES AE-3. Both use the 6SN7, which is less common than the 12AX7 variants but worth it, IMHO.
I run the Wright with a modded Hafler DH-200 and the combination is very good for a budget system.
I run the Wright with a modded Hafler DH-200 and the combination is very good for a budget system.