I think there is a lot of helpful advice in this tiny thread. The Carver 275 is a pretty good amp at very decent price. White the advice on a solid state alternative (First Watt F2) may not slake your curiosity over tube alternatives, it probably would deliver quite nice sound (I've heard the First Watt J2 and SIT amps and they are very good; I have not heard the F2). As I've stated before, I like OTL amps and the Atmasphere amps mentioned are very stable and reliable versions of such amps.
You could look into vintage gear, but that takes a bit of help from knowledgeable friends or a good dealer for a novice to get into that game. Old gear has to be inspected and perhaps repaired or reconditioned. Once that is done such gear can be reliable for a very long time.
For newer gear, it would be helpful to know what is the price range you are shopping. Also, if you are handy, you could save some money and get really good gear by building a kit. I heard the Elekit tu-8600 single-ended 300b amp, and it is terrific and the instructions look pretty straightforward and even a novice should be able to tackle that build. I noticed that Elekit also makes a single-ended amp kit utilizing the 6L6 tetrode tube (a personal favorite in type of tube) that looks interesting (I have not heard it). For lower-powered pushpull pentode/tetrode tube amps, I tend to like 6L6, KT66, and EL84, and EL34 tube types the most.