There are many great units, used Sonic Frontiers, Audio Research, Bottlehead, Conrad Johnson, TAD and a few others.....I think buying a used tube pre is going to get you alot more then a budget new unit but there are some tube units from China that are clones of pretty expensive units from USA and Europe. A nice tube pre is really going to warm up your sound and improve image and depth........I have owned Audio Research and right now use Sonic Frontiers. If you want any ideas email me. Cheers