Take any specific brand recommendations above with a grain of salt, as well as any that come after this post. These recommendations are useful only to the degree that you might want to include some of them on a short-list of gear that you want to audition. In the end, remember that the only thing that you can trust is your ears. But do listen to as much gear as you possibly can, decide what you like, and then buy it used here or in a similar forum.
While people are well intentioned, consider that when someone raves about a specific product, it's probably because they own it, and how objective can they really be? After all if you asked them if their wife/girlfriend is ugly, how many would respond with an objective "yes"? And believe me, I've listened to plenty of gear that people raved about here that left me cold.
Finally, recommendations that you buy used tube gear, and you'll get plenty, should be considered with a jaundiced eye. This is because you must periodically replace the tubes and this can cost a bunch of money, especially for power amps --- a real problem given that you stated that you are on a tight budget. It's similar to a friend asking you to recommend an economical car, and you recommend one that you know requires an engine replacement every 30,000 miles. It' just not a real budget friendly recommendation. Good luck.