EL34 in triode vs 300B/845 SET

AVR watts are generally not the best quality since the purpose is mostly for home theatre applications. If you're willing to go the used route, for $2500 you should be able to get a decent but older McIntosh 2channel amplifier, with Autoformers, and get the warm/transparent sound you're looking for. 

Only few people may agree but I firmly believe good sound comes from high current not high watts even though inter-related to some degree.

@hifineubeeThere really isn't any such thing as 'high current'; that's a bit of story created by solid state amp manufacturers. Current does not exist without voltage, and together the two are power. Its a mathematical relationship!

The reason 'neutral' (usually solid state, as opposed to 'warm') might seem unpleasant is due to how the amp distorts. In the case of solid state, the distortion seems minimal, but to the ear it is not, as the distortion in question is all higher ordered harmonics, to which the ear is keenly sensitive (the ear uses these harmonics to sense sound pressure, so has to be able to deal with 140db range, hence the sensitivity). So 0.0x% numbers in solid state amps are easily audible, heard as brightness and harshness.
Tube amps generally don't make as much higher ordered harmonics and so sound smoother and more detailed. Tubes usually do make more distortion overall, but its mostly lower orders and the ear simply is less sensitive to the lower orders. In a way, you can argue that tubes more closely adhere to the rules of human hearing perception. In a nutshell.
I'd be looking at something with 60 watts or so. You can find amps of that power inside of your budget, and that is significantly more power (and likely lower distortion and wider bandwidth too) than what you are running right now- you'll notice the improvement instantly!

Thanks Kalali and atmasphere, good tips.

@hifinubee based on your recent posts you seem willing to go in a different direction with the amplifier. I take it that means, given the choice, you prefer to keep the B&W loudspeakers?

SETs appeal to a lot of people. They often then start a quest to chase down a sympathetic loudspeaker to mate with them. I understand you really like the B&W, but I think it's easier to find a loudspeaker that works for you than another type of tube amplifier. If you do want a warm sound in a more powerful tube amplifier you may want to consider some of the BAT, Cary, Conrad Johnson, Jadis, and Quicksilver push-pull offerings. That said, in going there you likely give up what draws you to your current SET amplifier.

Coincidentally, I was the North American importer for Consonance. Just to clarify, the Reference 5.5 used only 2 X 300B per channel, and as its not at all a powerful amplifier, would not much more than you already have. If you want to go in the PSE direction, I recommend the Cyber 300B PSE monoblocks as a much better alternative, but still won't meet your current needs, as they are also seriously deficient in the low-end.  Consonance also produced 211 (great midrange, not much low-end) and 845 (good low-end, overly dark and veiled midrange) versions of the Cyber monoblocks, which work best with back-loaded horn loudspeakers. As I previously stated, neither of those larger tubes produce what people like so much about 300B amplifiers. SETs have ridden this popularity wave for more than 20 years, and with it, the larger tubes. So many people have found themselves in the same situation as you, loving the lower wattage amplifiers, but wishing for more output to adequately drive their loudspeakers. If the larger SETs represented the solution, they would have already caught on in a big way. As things are, the 300B handily outsells them, for good reason.  To provide acceptable power and bass response, you may also want to consider push-pull triode amplifiers, using 300B, or even better, 2A3 tubes

Sophia Electric has some sick 300B mono blocks.....